Fixture and method for polishing fiber optic connector ferrules

This application claims priority under 35 USC 109(e) to non-provisional application 62/770,679 filed on Nov. 21, 2018, titled “Fixture for Polishing a Fiber Optic Connector Having A Plural of Ferrules and Method of Use”, which is fully incorporated herein by reference.

The present invention relates to fiber optic connectors and receptacles, and more particularly, to a holder and tool for polishing and orienting a plural of ferrules.

Modern high capacity optical systems have multiple connection points in an optical path. Each connection point can lose up to 2 dB of signal or 1 dB of signal per a connector. Since an interconnect point as opposing connectors, there is up to 2 dB of signal loss. 2 db of signal loss translates into a power loss of 1.58 milli-Watt. Reducing signal loss at the connector is important when a system can hundreds of inter-connect junctions, or connector-to-connector points. To achieve a reduced loss, reflection losses that occur between the end face of opposing ferrules can be reduced. Refer to FIG. 9 . An APC connector or angled polished connector exhibits the lowest loss at 0.316 micro-watts or opposed to 1000 micro-watts for a flat cut of a ferrule end face for two opposing ferrules in an adapter. To achieve this low loss, the ferrule end is polished to an angle of eight (8) degrees. The prior art methods existing for single ferrule connectors but not duplex ferrule or quad ferrule connectors.

According to the present invention, a holder with a body portion is configured to hold a duplex fiber optic connector. A duplex connector has at least two ferrules surfaces requiring polishing at an APC cut. APC is called angled polished cut. In use, the connector is positioned in the holder such that the ferrule end faces can be both polished to an eight (8) degree cut. Once the ferrule end faces are polished, a tool is needed to rotate or orient the ferrule end faces about ninety (90) degrees. This is orientation will allow opposing connectors to abut at their end faces, so as to minimize reflection loss, as shown in FIG. 12 .

A receptacle is configured to accept a fiber optic connector, and secure said connector therein. An adapter has two opposing receptacles to interconnect two portions of a network. A first connector with a APC end face is inserted into a first receptacle, and a second connector with an APC end face is inserted in the second or opposing receptacle to the first. This forms the joint or interconnect point in a network that is suspect to a 2 decibel signal loss. By abutting opposing end faces with an APC polish over a flat polish at the end face, reflection power losses drop from 1000 micro-watts to 0.32 micro-watts.

Embodiments of the invention are described in more detail hereinafter with reference to the drawings, in which:

FIG. 1 depicts a prior art duplex ferrule connector.

FIG. 2 is an exploded view of FIG. 1 .

FIG. 2 A is a perspective view of an alternative duplex ferrule connector.

FIG. 3 is a perspective view of a ferrule assembly according to the present invention.

FIG. 4 is a front or proximal view of FIG. 1 connector with FIG. 3 ferrule assembly.

FIG. 5 A is a holder or jog for the connector of FIG. 1 .

FIG. 5 B is the connector of FIG. 1 secured in the holder of FIG. 5 A .

FIG. 5 C 1 is a top view of FIG. 5 A holder.

FIG. 5 C 2 is a side view of FIG. 5 A holder.

FIG. 5 C 3 is a front view of FIG. 5 A holder.

FIG. 5 C 4 is a view of a hook to secure connector of FIG. 1 within holder of FIG. 5 C 1 .

FIG. 6 is a prior art polishing jig for a single ferrule connector.

FIG. 7 A is the connector of FIG. 1 with its ferrule end faces polished to APC or 8 degree angle.

FIG. 7 B is the connector of FIG. 1 after APC polishing.

FIG. 7 C is the full insertion of the FIG. 1 connector within holder of FIG. 5 A .

FIG. 7 D is the connector of FIG. 1 after APC polishing,

FIG. 7 E is a side view and top view of ferrules after APC polishing.

FIG. 8 A is a tool to orient the ferrule assembly of FIG. 3 after the ferrule is APC polished.

FIG. 8 B is an exploded view of a second end of FIG. 8 A tool.

FIG. 9 is a table of reflection losses by end face polish type depicting reflection loss.

FIG. 10 A is FIG. 8 A tool secured to ferrule assembly to rotate ferrule after APC polish.

FIG. 10 B is rotation step of FIG. 1 A .

FIG. 10 C depicts removing the tool of FIG. 8 A off the ferrule.

FIG. 10 D depicts rotating the second ferrule.

FIG. 11 A depicts proper orientation of the APC polished ferrules.

FIG. 11 B is a side, front perspective view of the ferrules of FIG. 11 A .

FIG. 11 C depicts bottom view of ferrules after APC polish and orientation.

FIG. 12 depicts abutting two APC ferrule end faces to achieve minimal reflection loss.

In the following description, apparatuses for mating two multi-fiber optic ferrules. The ferrules end face being formed of an APC cut, as shown in FIG. 12 . It will be apparent to those skilled in the art that modifications, including additions and/or substitutions may be made without departing from the scope and spirit of the invention. Specific details may be omitted so as not to obscure the invention; however, the disclosure is written to enable one skilled in the art to practice the teachings herein without undue experimentation.

FIG. 1 depicts a prior art connector 100 having a plural of ferrule assembly ( 10 a , 10 b ). FIG. 2 is an exploded view of connector 100 depicting bias springs 3 , ferrule assembly ( 10 a , 10 b ), connector housing 2 , recess 12 , and a dust cap 1 . FIG. 2 A is an alternative duplex ferrule connector 200 with a connector housing 201 , alignment tab 205 and recess 212 . As with connector 100 , connector 200 recess is secured by a latch with holder 500 . Connector 200 has an alignment tab 205 which aids in placement of connector 200 within holder 500 .

FIG. 3 depicts a ferrule assembly with a ferrule having an optical fiber therein, and a flange with a pair of opposing slot cut outs ( 11 a . 1 , 11 a . 2 ). FIG. 4 depicts an end view or proximal view of connector 100 showing the ferrule assembly 10 a , 10 b and slot cutouts 11 a . 1 , 11 a . 2 and 11 b . 1 , 11 b . 2 respectively. The slot cut outs accept a corresponding protrusion at a second end of a tool as shown in FIG. 8 A .

FIG. 5 A is a holder or jig that accepts connector 100 in a configuration capable of applying an APC polish to both ferrule end faces at the same time. An APC polish places an 8 degree angle on a flat-end face ferrule. Prior art polishing is one ferrule at a time. The jig holds the connector at an 8 degree angle. The jig is secured to the face of a polishing surface, using a pair of tabs at the base of the holder. FIG. 5 B depicts connector 100 in holder 500 . FIG. 5 C 1 is a top view of holder 500 . FIG. 5 C 2 is a side view of holder 500 . FIG. 5 C 3 is a front view of holder 500 .

FIG. 5 C 4 depicts a hook comprising a body, holder 500 locking surfaces 114 , and flexible arms 112 . The arms 112 flex upward and are received in a recess 12 of connector upon insertion of connector 100 into holder 500 . locking surfaces 114 aid in securing hook 110 within cut-outs (not shown) within holder.

FIG. 6 is a prior art polishing jig 600 with a plural of holders 624 for securing a connector 620 with a single ferrule. By contrast, the present invention is a jig that can hold ABC polish two or more ferrules. The jig can be attached to the polisher surface 622 similar to holder 624 .

FIG. 7 A depicts connector 100 without an APC polish at the ferrule 10 a . FIG. 7 B depicts connector 100 with an APC polish applied to ferrule 10 a ′. FIG. 7 C depicts connector 100 within jig 500 prior to applying an APC polish. FIG. 7 D is a connector 100 after an ABC polish is applied to ferrule 10 a ′. FIG. 7 E depicts side view and top view of polish applied to ferrule tip 10 a′.

FIG. 8 A is an orienting tool 800 that rotates an APC polished ferrule 10 a ′, at the proximal end of connector 100 . A first end comprises a handle 812 and a second end comprises a tip with a pair of protrusions ( 816 a , 816 b ), connected by shaft 814 . FIG. 8 B is an exploded view of tip showing the protrusions.

FIG. 9 depicts various ferrule end face cuts, and a table of estimated reflection loss in decibels when two ferrules with the same end cut are opposing each other in an adapter. A more negative decibel means less power loss.

FIG. 10 A depicts tool 800 inserted in the direction “I” and secured to ferrule assembly 10 a . The tool protrusions ( 816 a , 816 b ) engage slot cuts ( 11 a . 1 , 11 a . 2 ) at the proximal end “P”, and user pushes the ferrule assembly in a distal direction and rotates (“R”) the ferrule assembly 10 a ′, by 90 degrees, in FIG. 10 B . In FIG. 10 C , the tool 800 is withdrawn proximally, and spring 3 a biases ferrule assembly forward (“RM”) in connector housing 2 . FIG. 10 D depicts using tool 800 to rotate the second ferrule assembly ( 10 b ′) 90 degrees, After both ferrule assembly ( 10 a ′, 10 b ′) are rotated 90 degrees, the APC cut ferrule end faces are in a proper orientation as shown by FIG. 11 A . FIG. 11 B depicts side view of polished ferrules to an APC angle of 8 degrees of FIG. 11 A . FIG. 11 C depicts bottom view of APC ferrules after orientation using tool 800 . FIG. 12 depicts abutting or inserting of a two connectors 100 after APC polish in an adapter (not shown). FIG. 12 shows how the APC polished end faces will abut with no air gap to reduce reflection loss, as estimated in FIG. 9 .

An ordinarily skilled person in the art can appreciate that by following the principal of the present invention, a version of the adapter for mating a multi-fiber optic ferrule with another multi-fiber optic ferrule can be derived without departing from the scope and spirit of the invention. Although the embodiments of the present invention described herein are related to multi-fiber optic applications, the present invention can be adapted to single fiber optic applications. Specific details may be omitted so as not to obscure the invention; however, the disclosure is written to enable one skilled in the art to practice the teachings herein without undue experimentation.

The foregoing description of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations will be apparent to the practitioner skilled in the art.

The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications that are suited to the particular use contemplated.