Beam-splitting integrated optical element and optical transmitter module

This application claims the priority benefit of Taiwan application serial no. 104143340, filed on Dec. 23, 2015. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of specification.

1. Field of the Invention

The invention relates to a beam-splitting integrated optical element and an optical transmitter module.

2. Description of Related Art

With advancements in communication technologies, communication methods are no longer limited only to be implemented by using electrical signals. Recently, optical communication technologies have been developed to realize signal transmission with optical signals. Because transmission speed and distance of light is far higher and longer than electrons, optical communication technologies have gradually become the mainstream in the market. Based on high bandwidth requirements, demands for optical transmitter modules capable of transmitting massive amount of optical signal become higher each day. To ensure stability in the signal transmission, the optical transmitter modules often need to synchronously monitor the optical power. The optical transmitter modules using the edge emitting laser can use the back emitting light to monitor the front emitting light (i.e., the light used for transmission), so as to synchronously monitor the optical power. The optical transmitter module using the surface emitting laser must utilize optical elements to split the transmitted light in order to monitor the optical power. Therefore, the design of beam-splitting integrated optical element plays a fairly important role.

FIG. 1 is a schematic cross-sectional view of a conventional optical transmitter module. Referring to FIG. 1 , an optical transmitter module 10 includes an optical element 12 , lenses 14 A, 14 B and 14 C, a light source 16 and an optical detector 18 . A beam B emitted by the light source 16 is collimated by the lens 14 A before entering the optical element 12 and then being transmitted to total internal reflection surfaces TIR 1 and TIR 2 . Bottom edges of the total internal reflection surfaces TIR 1 and TIR 2 are connected and perpendicular to each other, such that a vertex X is formed. The beam B is split by the total internal reflection surfaces TIR 1 and TIR 2 and the vertex X to be transmitted towards different directions, wherein the beam B reflected by the total internal reflection surface TIR 1 is converged into an optical fiber F through the lens 14 B to be applicable for the signal transmission. On the other hand, the beam B reflected by the total internal reflection surface TIR 2 is converged into the optical detector 18 through the lens 14 C to be applicable for monitoring the optical power. In other words, the optical transmitter module 10 is capable of conducting the signal transmission and monitoring the optical power synchronously.

Since the vertex X formed by connecting the total internal reflection surfaces TIR 1 and TIR 2 together are prone to have curvature due to manufacturing process factors, the beam B is prone to be scattered at the vertex X, resulting in an optical power loss and a beam-splitting ratio offset thereby lowering a yield rate of the optical transmitter module 10 . Further, during the assembly process of the optical transmitter module 10 , a passive machine alignment is usually performed by viewing an image of the light source 16 through the lens 14 B corresponding to the optical fiber F. However, in the architecture of the optical transmitter module 10 , the entire image of the light source 16 cannot be viewed through the lens 14 B since only a portion of the image of the light source 16 can be guided to the lens 14 B through the total internal reflection surface TIR 1 , such that an alignment difficulty and a calibration time may both be increased during the assembly process. Accordingly, how to solve the aforementioned problems has become one of important issues in the related art.

The invention is directed to a beam-splitting integrated optical element capable of preventing the scattering due to beam-splitting at the vertex in order to lower the optical power loss and the beam-splitting ratio offset and facilitate in reduction of the alignment difficulty and the alignment time for the optical transmitter module.

The invention is further directed to an optical transmitter module having a beam-splitting integrated optical element which can provide a preferable yield rate, low alignment difficulty and short alignment time.

A beam-splitting integrated optical element of the invention includes a shell, at least one first lens, and at least one second lens. The shell includes a first lens surface, a second lens surface, at least one first reflective surface, and at least one second reflective surface. The second lens surface is perpendicular to the first lens surface. The first reflective surface and the second reflective surface are located above the first lens surface. A bottom edge of each first reflective surface close to the first lens surface and a bottom edge of each second reflective surface close to the first lens surface are not connected to each other. The first lens is disposed on the first lens surface, and each first lens has a first optical axis. The second lens is disposed on the second lens surface, and each second lens has a second optical axis. The first reflective surface is located above the first lens and inclined to the first optical axis and the second optical axis. Each first reflective surface is adapted to reflect at least a portion of the first beam from the corresponding first lens so that the portion of the first beam is transmitted along a first direction parallel to the second optical axis. Each second reflective surface is located at at least one side of the corresponding second optical axis and located on a transmission path of another portion of the first beam, and inclining directions of the first reflective surface and the second reflective surface are opposite so that the another portion of the first beam transmitted to the second reflective surface is transmitted along a second direction different from the first direction after being reflected by the second reflective surface.

An optical transmitter module of the invention includes a beam-splitting integrated optical element, at least one first light source and at least one optical detector. The beam-splitting integrated optical element includes a shell, at least one first lens, and at least one second lens. The shell includes a first lens surface, a second lens surface, at least one first reflective surface, and at least one second reflective surface. The second lens surface is perpendicular to the first lens surface. The first reflective surface and the second reflective surface are located above the first lens surface. A bottom edge of each first reflective surface close to the first lens surface and a bottom edge of each second reflective surface close to the first lens surface are not connected to each other. The first lens is disposed on the first lens surface, and each first lens has a first optical axis. The second lens is disposed on the second lens surface, and each second lens has a second optical axis. The first light source is located below the first lens surface. Each first light source is disposed below one of the at least one first lens and adapted to emit a first beam towards the corresponding first lens. The first reflective surface is located above the first lens and inclined to the first optical axis and the second optical axis. Each first reflective surface is adapted to reflect at least a portion of the first beam from the corresponding first lens so that the portion of the first beam is transmitted along a first direction parallel to the second optical axis. Each second reflective surface is located at at least one side of the corresponding second optical axis and located on a transmission path of another portion of the first beam, and inclining directions of the first reflective surface and the second reflective surface are opposite so that the another portion of the first beam transmitted to the second reflective surface is transmitted along a second direction different from the first direction after being reflected by the second reflective surface. The optical detector is located on the transmission path of the another portion of the first beam reflected by the second reflective surface to receive the first beam reflected by the second reflective surface.

Based on the above, the beam-splitting integrated optical element of the invention adopts the design in which the bottom edges of the first reflective surface and the second reflective surface are not connected to each other in order to prevent formation of the vertex. As such, the optical power loss and the beam-splitting ratio offset caused by scattering of the beam at the vertex in the conventional art may be solved to improve the yield rate of the optical transmitter module, so as to facilitate improvements for the alignment difficulty and the alignment time induced by unclear image of the light source and incomplete borders caused by scattering of the beam at the vertex.

To make the above features and advantages of the invention more comprehensible, several embodiments accompanied with drawings are described in detail as follows.

The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

FIG. 1 is a schematic cross-sectional view of a conventional optical transmitter module.

FIG. 2A is a schematic top view of an optical transmitter module according to a first embodiment of the invention.

FIG. 2B and FIG. 2C are respectively schematic cross-sectional views along section lines A-A′ and B-B′ in FIG. 2A .

FIG. 2D and FIG. 2E are schematic diagrams of an optical path of the optical transmitter module in FIG. 2A .

FIG. 2F and FIG. 2G are respectively schematic diagrams of optical fields OF 1 and OF 2 in FIG. 2D .

FIG. 2H is a schematic diagram of an optical field OF 3 in FIG. 2E .

FIG. 3A is a schematic top view of an optical transmitter module according to a second embodiment of the invention.

FIG. 3B and FIG. 3C are respectively schematic cross-sectional views along section lines A-A′ and B-B′ in FIG. 3A .

FIG. 3D and FIG. 3E are schematic diagrams of an optical path of the optical transmitter module in FIG. 3A .

FIG. 4A is a schematic top view of an optical transmitter module according to a third embodiment of the invention.

FIG. 4B and FIG. 4C are respectively schematic cross-sectional views along section lines A-A′ and B-B′ in FIG. 4A .

FIG. 4D and FIG. 4E are schematic diagrams of an optical path of the optical transmitter module in FIG. 4A .

FIG. 5A is a schematic top view of an optical transmitter module according to a fourth embodiment of the invention.

FIG. 5B to FIG. 5D are respectively schematic cross-sectional views along section lines A-A′, B-B′ and C-C′ in FIG. 5A .

FIG. 5E to FIG. 5G are schematic diagrams of an optical path of the optical transmitter module in FIG. 5A .

FIG. 5H and FIG. 5I are respectively schematic diagrams of optical fields OF 1 and OF 2 in FIG. 5E .

FIG. 5J is a schematic diagram of an optical field OF 3 in FIG. 5F .

FIG. 5K is a schematic diagram of an optical field OF 4 in FIG. 5G .

FIG. 6A is a schematic top view of an optical transmitter module according to a fifth embodiment of the invention.

FIG. 6B to FIG. 6D are respectively schematic diagrams of optical fields of the optical transmitter module of FIG. 6A corresponding to the optical fields OF 1 and OF 2 in FIG. 5E and the optical field OF 3 in FIG. 5G .

FIG. 7A is a schematic top view of an optical transmitter module according to a sixth embodiment of the invention.

FIG. 7B and FIG. 7C are schematic oblique views of the optical transmitter module in FIG. 7A under different viewing angles.

FIG. 8A is a schematic top view of an optical transmitter module according to a seventh embodiment of the invention.

FIG. 8B and FIG. 8C are schematic oblique views of the optical transmitter module in FIG. 8A under different viewing angles.

FIG. 9A and FIG. 9B are respectively schematic oblique views of an optical transmitter module according to an eighth embodiment of the invention under different viewing angles.

Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.

FIG. 2A is a schematic top view of an optical transmitter module according to a first embodiment of the invention. FIG. 2B and FIG. 2C are respectively schematic cross-sectional views along section lines A-A′ and B-B′ in FIG. 2A . FIG. 2D and FIG. 2E are schematic diagrams of an optical path of the optical transmitter module in FIG. 2A . FIG. 2F and FIG. 2G are respectively schematic diagrams of optical fields OF 1 and OF 2 in FIG. 2D . FIG. 2H is a schematic diagram of an optical form OF 3 in FIG. 2E .

Referring to FIG. 2A to FIG. 2H , an optical transmitter module 100 includes a beam-splitting integrated optical element 110 , at least one first light source 120 and at least one optical detector 130 . In this embodiment, the number of each of the first light source 120 and the optical detector 130 is one, but not limited thereto.

The beam-splitting integrated optical element 110 includes a shell SH, at least one first lens L 1 , and at least one second lens L 2 . In this embodiment, the number of each of the first lens L 1 and the second lens L 2 is one, but not limited thereto. All the elements in the beam-splitting integrated optical element 110 may be integrally formed as one. Specifically, the beam-splitting integrated optical element 110 may be manufactured by molding, and a material of the beam-splitting integrated optical element 110 may be Ultem, but not limited thereto.

Referring to FIG. 2B and FIG. 2C , the shell SH includes a first lens surface S 1 , a second lens surface S 2 , at least one first reflective surface R 1 , and at least one second reflective surface R 2 . The second lens surface S 2 is perpendicular to the first lens surface S 1 . The first reflective surface R 1 and the second reflective surface R 2 are located above the first lens surface S 1 . A bottom edge BE 1 of each first reflective surface R 1 close to the first lens surface S 1 and a bottom edge BE 2 of each second reflective surface R 2 close to the first lens surface S 1 are not connected to each other. In this embodiment, the number of each of the first reflective surface R 1 and the second reflective surface R 2 is one, but not limited thereto.

Referring to FIG. 2D and FIG. 2E , the first lens L 1 is disposed on the first lens surface S 1 , and each first lens L 1 has a first optical axis OA 1 . The first light source 120 is located below the first lens surface S 1 . Each first light source 120 is disposed below one of the at least one first lens L 1 and adapted to emit a first beam B 1 towards the corresponding first lens L 1 . The first light source 120 may be a laser light source, such as a surface-emitting laser, but not limited thereto. The first lens L 1 faces the first light source 120 , and the first lens L 1 is adapted to collimate the first beam B 1 from the first light source 120 . Based on different design requirements, shapes of the first lens L 1 and the collimated beam (indicated by dash line in FIG. 2A ) may be circle or oval. FIG. 2A shows that the shapes of the first lens L 1 and the collimated beam are circle, but not limited thereto.

The second lens L 2 is disposed on the second lens surface S 2 , and each second lens L 2 has a second optical axis OA 2 . The second lens L 2 faces an optical fiber F coupled to the beam-splitting integrated optical element 110 , and the second lens L 2 is adapted to converge a portion of the first beam B 1 (e.g., a first beam B 11 ) into the optical fiber F.

The first reflective surface R 1 is located above the first lens L 1 and inclined to the first optical axis OA 1 and the second optical axis OA 2 . Each first reflective surface R 1 is adapted to reflect at least a portion of the first beam B 1 from the corresponding first lens L 1 so that at least the portion of the first beam B 1 (e.g., the first beam B 11 ) is transmitted along a first direction D 1 parallel to the second optical axis OA 2 . The first reflective surface R 1 can reflect the first beam B 1 by the total internal reflection method or a reflective film coated thereon. In the former architecture, an interior angle θ 1 (referring to FIG. 2B ) sandwiched by the first reflective surface R 1 and a plane where the first lens L 1 is located (e.g., the first lens surface S 1 ) is, for example, 45 degrees.

Referring to FIG. 2A and FIG. 2E , each second reflective surface R 2 is located at at least one side of the corresponding second optical axis OA 2 and located on a transmission path of another portion of the first beam B 1 (e.g., a first beam B 12 ), and inclining directions of the first reflective surface R 1 and the second reflective surface R 2 are opposite so that the first beam B 12 transmitted to the second reflective surface R 2 is transmitted along a second direction D 2 different from the first direction D 1 after being reflected by the second reflective surface R 2 . The second reflective surface R 2 can reflect the first beam B 12 by the total internal reflection method or a reflective film coated thereon. In the former architecture, the second reflective surface R 2 is perpendicular to the first reflective surface R 1 , that is, an interior angle θ 2 (referring to FIG. 2C ) sandwiched by the second reflective surface R 2 and the first reflective surface R 1 is 90 degrees.

Referring to FIG. 2D and FIG. 2E , the second reflective surface R 2 of the present embodiment is located between the first reflective surface R 1 and the second lens surface S 2 . The first beam B 1 from the first light source 120 is transmitted to the first reflective surface R 1 after being collimated by the first lens L 1 . The first reflective surface R 1 reflects the first beam B 1 so that the first beam B 1 is transmitted in the first direction D 1 perpendicular to the first optical axis OA 1 . The portion of the first beam B 1 (e.g., the first beam B 11 ) transmitted along the first direction D 1 is converged into the optical fiber F corresponding to the beam-splitting integrated optical element 110 by the corresponding second lens L 2 . On the other hand, the another portion of the first beam B 1 (e.g., the first beam B 12 ) transmitted along the first direction D 1 is reflected by the second reflective surface R 2 to change direction again to be transmitted along the second direction D 2 perpendicular to the first direction D 1 . The optical detector 130 is disposed corresponding to the second reflective surface R 2 and adapted to receive the first beam B 12 .

The beam-splitting integrated optical element 110 may further include at least one third lens L 3 . The third lens L 3 is located on the transmission path of the first beam B 12 reflected by the second reflective surface R 2 , and the first beam B 12 reflected by the second reflective surface R 2 passes through the corresponding third lens L 3 along the second direction D 2 to be converged by the third lens L 3 to the optical detector 130 . In this embodiment, the number of the third lens L 3 is one, but not limited thereto.

The beam-splitting integrated optical element 110 adopts the design in which the bottom edges of the first reflective surface R 1 and the second reflective surface R 2 are not connected to each other in order to prevent the vertex X in FIG. 1 from causing beam-splitting. As such, the optical power loss and the beam-splitting ratio offset caused by scattering of the beam at the vertex X in the conventional art may be solved to improve the yield rate of the optical transmitter module, so as to facilitate improvements for the alignment difficulty and the alignment time induced by unclear image of the light source and incomplete borders caused by scattering of the beam at the vertex X. Accordingly, the optical transmitter module 100 can provide a more preferable yield rate, a lower alignment difficulty and a shorter alignment time.

It is worth mentioning that, a beam-splitting ratio (i.e., an integration ratio of light intensity and area in a cross section of the first beam B 11 in FIG. 2G and a cross section of the first beam B 12 in FIG. 2H ) may be varied by varying a width WR 2 of the second reflective surface R 2 in the present embodiment. More specifically, referring to FIG. 2A , a beam maximum width of the first beam B 1 from the first light source 120 collimated by the first lens L 1 (indicated by dash line in FIG. 2A ) is WMAX. The beam maximum width WMAX is overlapped with the second reflective surface R 2 having the width WR 2 in a third direction D 3 , and an overlapped width WO is smaller than the beam maximum width WMAX. The second reflective surface R 2 may receive more of the first beam B 1 if the overlapped width WO is greater, whereas the second reflective surface R 2 may receive less of the first beam B 1 if the overlapped width WO is smaller. With a center position and the beam maximum width WMAX of the first beam B 1 in the first direction D 1 remaining unchanged, if the width WR 2 of the second reflective surface R 2 is greater, the overlapped width WO is greater and a proportion of the first beam B 12 in the first beam B 1 is greater. In other words, a size of the width WR 2 of the second reflective surface R 2 or the overlapped width WO may be used to vary the beam-splitting ratio. As compared to the optical transmitter module 10 of FIG. 1 which requires fine-tuning relative positions of the light source 16 and the vertex X where the total internal reflection surfaces TIR 1 and TIR 2 are intersected in order to vary the beam-splitting ratio, the method of varying the beam-splitting ratio by utilizing the width WR 2 of the second reflective surface R 2 in the present embodiment may be relatively more precise and more efficient for providing a greater alignment tolerance.

Further, since it does not require a high optical energy to monitor the optical power, a center beam (i.e., an area where the optical energy is strongest) of the first beam B 1 of the present embodiment may all be transmitted to the optical fiber F for the signal transmission. As compared to the center beam of the beam B in FIG. 1 which is easily scattered by the vertex X, the present embodiment is capable of maintaining the optical energy in the signal transmission.

FIG. 3A is a schematic top view of an optical transmitter module according to a second embodiment of the invention. FIG. 3B and FIG. 3C are respectively schematic cross-sectional views along section lines A-A′ and B-B′ in FIG. 3A . FIG. 3D and FIG. 3E are schematic diagrams of an optical path of the optical transmitter module in FIG. 3A . Referring to FIG. 3A to FIG. 3E , an optical transmitter module 200 is similar to the optical transmitter module 100 , and the same elements are indicated by the same reference numbers, which are not repeated hereinafter.

A major difference between the optical transmitter module 200 and the optical transmitter module 100 is that, in a beam-splitting integrated optical element 210 , a first reflective surface R 1 and a second reflective surface R 2 of a shell SHA are arranged in the third direction D 3 perpendicular to the first optical axis OA 1 and the second optical axis OA 2 . Further, the projection of the first lens L 1 is overlapped with the first reflective surface R 1 and the second reflective surface R 2 so that after the first beam B 1 from the first light source 120 is collimated by the first lens L 1 (the beam maximum width being WMAX), a portion of the first beam B 1 is irradiated on the first reflective surface R 1 while another portion is irradiated on the second reflective surface R 2 .

In addition, the shell SHA further includes at least one third reflective surface R 3 . In this embodiment, the number of the third reflective surface R 3 is one, but not limited thereto. Referring to FIG. 3E , the third reflective surface R 3 is inclined to and located above the first lens surface S 1 . Inclining directions of the third reflective surface R 3 and the second reflective surface R 2 are opposite and the third reflective surface R 3 is located on the transmission path of the first beam B 12 reflected by the second reflective surface R 2 . After being reflected by the second reflective surface R 2 , the first beam B 12 is transmitted to the third reflective surface R 3 along the second direction D 2 opposite to the first direction D 1 . The third reflective surface R 3 transmits the first beam B 12 from the second reflective surface R 2 to the optical detector 130 in a fourth direction D 4 parallel to the first optical axis OA 1 . The third reflective surface R 3 can reflect the beam transmitted in the beam-splitting integrated optical element 210 by the total internal reflection method or a reflective film coated thereon. In the former architecture, an interior angle θ 3 (referring to FIG. 3B ) sandwiched by the third reflective surface R 3 and a plane where the first lens L 1 is located (e.g., the first lens surface S 1 ) is, for example, 45 degrees.

The beam-splitting integrated optical element 210 may further include at least one third lens L 3 . The third lens L 3 is disposed on the first lens surface S 1 and located below the third reflective surface R 3 . After being reflected by the third reflective surface R 3 , the first beam B 12 is converged by the third lens L 3 to the optical detector 130 along the fourth direction D 4 . In this embodiment, the number of the third lens L 3 is one, but not limited thereto.

The beam-splitting integrated optical element 210 can also solve the optical power loss and the beam-splitting ratio offset caused by scattering of the beam at the vertex X of FIG. 1 in the conventional art by the design in which the bottom edges of the first reflective surface R 1 and the second reflective surface R 2 are not connected to each other, so that the optical transmitter module 200 using the beam-splitting integrated optical element 210 can also have more preferable light utilization and beam-splitting ratio uniformity as well as advantages of low alignment difficulty and short alignment time.

Further, the beam-splitting ratio may also be varied by varying the width WR 2 of the second reflective surface R 2 in the present embodiment. Alternatively, the beam-splitting ratio may be varied by varying a ratio of a width WR 1 of the first reflective surface R 1 and the width WR 2 of the second reflective surface R 2 in the third direction D 3 . More specifically, referring to FIG. 3A , with the center position and the maximum width WMAX of the first beam B 1 remaining unchanged, the ratio of the width WR 1 of the first reflective surface R 1 and the width WR 2 of the second reflective surface R 2 will influence the overlapped width WO of the first beam B 1 and the second reflective surface R 2 . The overlapped width WO is smaller if the width WR 1 of the first reflective surface R 1 is greater. On the other hand, the overlapped width WO is greater if the width WR 1 of the first reflective surface R 1 is smaller. As compared to the optical transmitter module 10 of FIG. 1 which requires fine-tuning relative positions of the light source 16 and the vertex X where the total internal reflection surfaces TIR 1 and TIR 2 are intersected in order to vary the beam-splitting ratio, the method of varying the beam-splitting ratio by utilizing the width WR 2 of the second reflective surface R 2 or varying the ratio of the width WR 1 of the first reflective surface R 1 and the width WR 2 of the second reflective R 2 in the present embodiment is relatively more precise and more efficient and can provide a greater alignment tolerance.

Further, since it does not require a high optical energy to monitor the optical power, a center beam (i.e., an area where the optical energy is strongest) of the first beam B 1 may all be transmitted to the optical fiber F for the signal transmission. As compared to the center beam of the beam B in FIG. 1 which is easily scattered by the vertex X, the present embodiment is capable of maintaining a signal transmission amount.

FIG. 4A is a schematic top view of an optical transmitter module according to a third embodiment of the invention. FIG. 4B and FIG. 4C are respectively schematic cross-sectional views along section lines A-A′ and B-B′ in FIG. 4A . FIG. 4D and FIG. 4E are schematic diagrams of an optical path of the optical transmitter module in FIG. 4A . Referring to FIG. 4A to FIG. 4E , an optical transmitter module 300 is similar to the optical transmitter module 200 , where the same elements are indicated by the same reference numbers, and thus the disposition relation and effectiveness related thereto are not repeated hereinafter.

A major difference between the optical transmitter module 300 and the optical transmitter module 200 is that, in a beam-splitting integrated optical element 310 , a shell SHB has a plane S 3 as replacement to the third reflective surface R 3 . The plane S 3 is connected and perpendicular to the first lens surface S 1 , and the third lens L 3 is disposed on the plane S 3 .

Referring to FIG. 4D and FIG. 4E , after the first beam B 1 from the first light source 120 is collimated by the first lens L 1 , a portion of the first beam B 1 (e.g., the first beam B 11 ) passes through the corresponding second lens surface S 2 along the first direction D 1 to be converged into the optical fiber F after being reflected by the first reflective surface R 1 . Another portion of the first beam B 1 (e.g., the first beam B 12 ) is transmitted along the second direction D 2 and converged to the optical detector 130 through the third lens L 3 after being reflected by the second reflective surface R 2 . It is worth mentioning that, in such architecture, another optical fiber F (not illustrated) may also be used to replace the optical detector 130 so that optical signal may be divided into two to be transmitted to different targets.

In each of the beam-splitting integrated optical elements 110 , 210 and 310 , a number ratio of the first reflective surface R 1 and the second reflective surface R 2 is 1:1, and the second reflective surface R 2 is located at one single side of the second optical axis OA 2 . Specifically, the second optical axis OA 2 of each second lens L 2 passes through the first reflective surface R 1 but does not pass through any second reflective surface R 2 , and the second reflective surface R 2 and the second optical axis OA 2 are arranged along the third direction D 3 . However, the invention is not limited to the above. In another embodiment, the shell may include two second reflective surfaces R 2 , that is, the number ratio of the first reflective surface R 1 and the second reflective surface R 2 is 1:2. The two second reflective surfaces R 2 may be respectively located at two sides of the second optical OA 2 , and the second reflective surfaces R 2 and the second optical axis OA 2 are arranged along the third direction D 3 . Accordingly, the beam-splitting integrated optical element may also include similar functions above or even more extended functions (e.g., an integrity of the center beam may be effectively maintained, but not limited thereto), which are omitted herein.

FIG. 5A is a schematic top view of an optical transmitter module according to a fourth embodiment of the invention. FIG. 5B to FIG. 5D are respectively schematic cross-sectional views along section lines A-A′, B-B′ and C-C′ in FIG. 5A . FIG. 5E to FIG. 5G are schematic diagrams of an optical path of the optical transmitter module in FIG. 5A . FIG. 5H and FIG. 5I are respectively schematic diagrams of optical fields OF 1 and OF 2 in FIG. 5E . FIG. 5J is a schematic diagram of an optical field OF 3 in FIG. 5F . FIG. 5K is a schematic diagram of an optical field OF 4 in FIG. 5G . Referring to FIG. 5A to FIG. 5K , an optical transmitter module 400 is similar to the optical transmitter module 300 , where the same elements are indicated by the same reference numbers, and thus the disposition relation and effectiveness related thereto are not repeated hereinafter.

A major difference between the optical transmitter module 400 and the optical transmitter module 300 is that, in a beam-splitting integrated optical element 410 , a shell SHC includes two second reflective surfaces R 2 , that is, the number ratio of the first reflective surface R 1 and the second reflective surface R 2 is 1:2. The two second reflective surfaces R 2 are arranged along the third direction D 3 at two sides of the second optical axis OA 2 .

In addition, the shell SHC further includes at least one third reflective surface R 3 ′. In this embodiment, the number of the third reflective surface R 3 ′ is one, but not limited thereto. The third reflective surface R 3 ′ is located above the first lens surface S 1 , and the third reflective surface R 3 ′ is located between one of the second reflective surface R 2 and a third surface S 3 . A width WR 3 ′ of the third reflective surface R 3 ′ in the third direction D 3 is at least partially overlapped with the width WR 2 of the corresponding second reflective surface R 2 in the third direction D 3 so as to effectively transmit the beam from the corresponding second reflective surface R 2 .

Referring to FIG. 5C and FIG. 5F , the third reflective surface R 3 ′ is inclined to the first optical axis OA 1 and the second optical axis OA 2 , and inclining directions of the third reflective surface R 3 ′ and the second reflective surface R 2 are opposite. The third reflective surface R 3 ′ can reflect the beam transmitted in the beam-splitting integrated optical element 410 by the total internal reflection method or a reflective film coated thereon. In the former architecture, an interior angle θ 4 sandwiched by the third reflective surface R 3 ′ and the second reflective surface R 2 is, for example, 90 degrees.

Further, the beam-splitting integrated optical element 410 may further include at least one third lens L 3 and at least one fourth lens L 4 . In this embodiment, the number of each of the third lens L 3 and the fourth lens L 4 is one, but not limited thereto. The third lens L 3 is disposed on the first lens surface S 1 and disposed below the third reflective surface R 3 ′, wherein a first lens L 1 A is located between the third lens L 3 and the second lens L 2 .

Referring to FIG. 5G , the fourth lens L 4 is disposed on the third surface S 3 and located on a transmission path of a portion of the first beam B 1 (e.g., a first beam B 12 B) from the second reflective surface R 2 , wherein the third lens L 3 is located between the fourth lens L 4 and the first lens L 1 A. In addition, the number of the optical detector 130 is two, wherein one of the optical detectors 130 is disposed below the third reflective surface R 3 ′ and disposed corresponding to the third lens L 3 , and another one of the optical detectors 130 is disposed corresponding to the fourth lens L 4 .

Referring to FIG. 5E to FIG. 5G , after the first beam B 1 from the first source 120 is collimated by the first lens L 1 A, a portion of the first beam B 1 (e.g., the first beam B 11 ) passes through the corresponding second lens L 2 along the first direction D 1 to be converged into the optical fiber F by the corresponding second lens L 2 after being reflected by the first reflective surface R 1 . The another portion of the first beam B 1 is divided into a first sub beam B 12 A and a second sub beam B 12 B by the two second reflective surfaces R 2 . The first sub beam B 12 A is transmitted to the third reflective surface R 3 ′ along the second direction D 2 after being reflected by the second reflective surface R 2 , and then passes through the corresponding third lens L 3 along the fourth direction D 4 to be converged to the optical detector 130 after being reflected by third reflective surface R 3 ′. The second sub beam B 12 B is transmitted to the third surface S 3 along the second direction D 2 after being reflected by the second reflective surface R 2 , and then passes through the corresponding fourth lens L 4 to be converged to the another optical detector 130 by the fourth lens L 4 . It is worth mentioning that, in such architecture, another optical fiber F (not illustrated) may also be used as replacement to the another optical detector 130 outside the fourth lens L 4 so that the optical signal transmission may be divided into two to be transmitted to different targets.

Beam-splitting ratios of the first beam B 11 , the first sub beam B 12 A and the second sub beam B 12 B may be varied by varying the widths of the first reflective surface R 1 and each of the second reflective surfaces R 2 in the present embodiment. Further, with division for the first sub beam B 12 A and the second sub beam B 12 B, the first sub beam B 12 A and the second sub beam B 12 B may be provided for different usages. For instance, during an active optical path calibration, whether the first light source 120 is precisely disposed on a preset optical path may be determined by observing the optical form or the optical power of the first sub beam B 12 A and the second sub beam B 12 B. Alternatively, at least one of the first sub beam B 12 A and the second sub beam B 12 B may be used to observe a relative displacement of the first light source 120 and the first lens L 1 A in different ambient temperatures or may be used for other signal transmission.

In addition, by changing the design of the first lens L 1 A, the first light source 120 can be collimated as an elliptic cylinder form, such that the energies of the first sub beam B 11 , the first sub beam B 12 A and the second sub beam B 12 B may be re-distributed for other usages in the present embodiment. It should be noted that, modifications made to the shape of the first lens L 1 A are also applicable to other beam-splitting integrated optical elements, and related description thereof is omitted hereinafter.

In the foregoing embodiments, each of the optical transmitter modules is only disposed with one single light source, but the invention is not limited thereto. FIG. 6A is a schematic top view of an optical transmitter module according to a fifth embodiment of the invention. FIG. 6B to FIG. 6D are respectively schematic diagrams of optical fields of the optical transmitter module of FIG. 6A corresponding to the optical fields OF 1 and OF 2 in FIG. 5E , and the optical field OF 3 in FIG. 5F . Referring to FIG. 6A to FIG. 6D , an optical transmitter module 500 is similar to the optical transmitter module 200 , where the same elements are indicated by the same reference numbers, and thus the disposition relation and effectiveness related thereto are not repeated hereinafter. A major difference between the optical transmitter module 500 and the optical transmitter module 200 is that, the optical transmitter module 500 is disposed with light sources with different wavelengths for applications in the wavelength division multiplexing.

To be specific, in a beam-splitting integrated optical element 510 , a shell SHD includes two second reflective surfaces R 2 , that is, the number ratio of the first reflective surface R 1 and the second reflective surface R 2 is 1:2. Further, the number of each of a first lens L 1 B, the third lens L 3 and the optical detector 130 is two. Each of the first lenses L 1 B is disposed below the first reflective surface R 1 and one of the second reflective surfaces R 2 so that each of the projection of the first lenses L 1 B is overlapped with a partial area of the first reflective surface R 1 and overlapped with a partial area of one of the second reflective surfaces R 2 . Therefore, after the first beam B 1 from the first light source 120 is collimated by the first lens L 1 B (the beam maximum width being WMAX), a portion of the first beam B 1 is irradiated on the first reflective surface R 1 while another portion is irradiated on the second reflective surface R 2 . In addition, each of the optical detectors 130 is disposed below one of the third lenses L 3 .

The optical transmitter module 500 further includes at least one second light source 120 A. In this embodiment, the number of the second light source 120 A is one, but not limited thereto. The second light source 120 A is located below one of the first lenses L 1 B. When the number of each of the first light source 120 and the second light source 120 A is greater than one, the first light sources 120 and the second light sources 120 A are arranged along the third direction D 3 .

The first light source 120 is adapted to emit the first beam B 1 towards one of the first lenses L 1 B, and the first beam B 1 is collimated by said one of first lenses L 1 B. The second light source 120 A is adapted to emit a second beam B 2 towards another one of the first lenses LIB, and the second beam B 2 is collimated by said another one of the first lenses L 1 B. A wavelength of the second beam B 2 is different from a wavelength of the first beam B 1 . The first reflective surface R 1 is adapted to reflect a portion of the first beam B 1 from said one of the first lenses L 1 B and a portion of the second beam B 2 from said another one of the first lenses L 1 B and transmit said portion of the first beam B 1 (e.g., the first beam B 11 ) and said portion of the second beam B 2 (e.g., a second beam B 21 ) along the first direction D 1 , so that the first beam B 11 and the second beam B 21 can pass through the second lens L 2 to be converged together to an optical fiber that is not illustrated. On the other hand, each of the second reflective surfaces R 2 arranged at two sides of the second optical axis OA 2 is adapted to respectively transmit another portion of the first beam B 1 (e.g., the first beam B 12 ) and another portion of the second beam B 2 (e.g., a second beam B 22 ) along the second direction D 2 , and the corresponding optical detectors 130 are adapted to receive the first beam B 12 and the second beam B 22 , respectively.

FIG. 7A is a schematic top view of an optical transmitter module according to a sixth embodiment of the invention. FIG. 7B and FIG. 7C are schematic oblique views of the optical transmitter module in FIG. 7A under different viewing angles. Referring to FIG. 7A to FIG. 7C , an optical transmitter module 600 is similar to the optical transmitter module 100 , where same elements are indicated by the same reference numbers, and thus the disposition relation and effectiveness related thereto are not repeated hereinafter.

A major difference between the optical transmitter module 600 and the optical transmitter module 100 is that, a beam-splitting integrated optical element 610 of the optical transmitter module 600 further includes a optical fiber connector FC for connecting the optical fiber F in FIG. 2D and FIG. 2E . The optical fiber connector FC is disposed on the second lens L 2 and connected to a shell SHE. The optical fiber connector FC may be a LC connector (Lucent Connector) or connectors in other forms. It should be noted that, the beam-splitting integrated optical elements in the foregoing embodiments may also include the optical fiber connector FC, and related description thereof is omitted hereinafter.

FIG. 8A is a schematic top view of an optical transmitter module according to a seventh embodiment of the invention. FIG. 8B and FIG. 8C are schematic oblique views of the optical transmitter module in FIG. 8A under different viewing angles. Referring to FIG. 8A to FIG. 8C , an optical transmitter module 700 is similar to the optical transmitter module 100 , where the same elements are indicated by the same reference numbers, and thus the disposition relation and effectiveness related thereto are not repeated hereinafter.

A major difference between the optical transmitter module 700 and the optical transmitter module 100 is that, a beam-splitting integrated optical element 710 further includes at least one fifth lens L 5 , and a shell SHF further includes at least one fourth reflective surface R 4 . In this embodiment, the number of each of the fifth lens L 5 and the fourth reflective surface R 4 is one, but not limited thereto. The fifth lens L 5 is disposed at one side of the second lens L 2 . The fifth lens L 5 has a third optical axis OA 3 , and the fourth reflective surface R 4 is located on a transmission path of a beam from the fifth lens L 5 and disposed along the third optical axis OA 3 .

Further, the beam-splitting integrated optical element 710 may further include a third lens L 3 A, and the optical transmitter module 700 may further include an optical detector 130 A, wherein the third lens L 3 A and the optical detector 130 A are disposed corresponding to the fourth reflective surface R 4 . After a beam from the outside enters the optical transmitter module 700 through the optical fiber connector to be collimated by the fifth lens L 5 , said beam is sequentially reflected to the third lens L 3 A by the fourth reflective surface R 4 and then converged to the optical detector 130 A. In such architecture, the optical transmitter module 700 not only include the transmitting function but also include the receiving function. In other words, the optical transmitter module 700 may serve as an optical transceiver module.

FIG. 9A and FIG. 9B are respectively schematic oblique views of an optical transmitter module according to an eighth embodiment of the invention under different viewing angles. Referring to FIG. 9A and FIG. 9B , an optical transmitter module 800 is similar to the optical transmitter module 700 , where the same elements are indicated by the same reference numbers, and thus the disposition relation and effectiveness related thereto are not repeated hereinafter.

A major difference between the optical transmitter module 800 and the optical transmitter module 700 is that, the number of the optical detectors 130 A of the optical transmitter module 800 is greater than one. Further, in a beam-splitting integrated optical element 810 , the number of the second reflective surface R 2 of a shell SHG is greater than one, and the number of each of the first lens L 1 , the second lens L 2 , the third lens L 3 , the third lens L 3 A and the fifth lens L 5 is greater than one, and all said elements may be arranged in an array in order to realize functions of multiple channels beam-splitting.

With the disposition of the fifth lens L 5 and the third lens L 3 A, the optical transmitter module 800 is capable of receiving external beams. Specifically, when a beam from the outside enters the beam-splitting integrated optical element 810 after being collimated by the fifth lens L 5 , said beam is then reflected by the first reflective surface R 1 to pass through the third lens L 3 A to be converged to the optical detector 130 A. In such architecture, the optical transmitter module 800 not only include the transmitting function but also include the receiving function. In other words, the optical transmitter module 800 may serve as an optical transceiver module.

In summary, the beam-splitting integrated optical element of the invention adopts the design in which the bottom edges of the first reflective surface and the second reflective surface are not connected to each other in order to prevent formation of the beam-splitting vertex in the conventional art. As such, the optical power loss and the beam-splitting ratio offset caused by scattering of the beam at the vertex in the conventional art may be solved, so as to facilitate improvements for adverse effects on clarity of the image from light source and integrity of borders caused by scattering of the beam at the vertex. Therefore, other than reducing the alignment difficulty and the alignment time, the beam-splitting integrated optical element can also solve the optical power loss caused by scattering of the beam at the vertex in the conventional art, so that the optical transmitter module using the beam-splitting integrated optical element can also have more preferable light utilization in addition to advantages of low alignment difficulty and short alignment time. In one embodiment, the beam-splitting ratio and the signal transmission amount may also be effectively varied by varying the width of the second reflective surface in the third direction perpendicular to the first optical axis and the second optical axis.

It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.