Optical connector with polarization maintaining fiber

Abstract

An optical ferrule assembly configured for use in an optical connector includes an optical ferrule, an optical fiber retainer, and a plurality of polarization-maintaining optical fibers. Each polarization-maintaining optical fiber has a core surrounded by a cladding and a cladding surrounded by a buffer. The buffer is stripped away from a fiber end of the polarization-maintaining optical fiber to form a stripped portion exposing the cladding, the stripped portion being disposed between first and second non-stripped portions of the polarization-maintaining optical fiber. The first non-stripped portion extends from the stripped portion toward the fiber end of the polarization-maintaining optical fiber. The fiber end is permanently attached to the optical ferrule, and the exposed cladding of the stripped portion is permanently attached to the optical fiber retainer.

Description

Summary of the Invention

[0001] In some aspects herein, an optical ferrule assembly configured for use in an optical connector is provided, the optical ferrule assembly including an optical ferrule, an optical fiber retainer, and a plurality of polarization-maintaining optical fibers. Each polarization-maintaining optical fiber has a core surrounded by a cladding and a cladding surrounded by a buffer. The buffer is stripped away from a fiber end of the polarization-maintaining optical fiber to form a stripped portion exposing the cladding. The stripped portion is disposed between a first and a second non-stripped portion of the polarization-maintaining optical fiber. The first non-stripped portion extends from the stripped portion toward the fiber end of the polarization-maintaining optical fiber. Each fiber end of the plurality of polarization-maintaining optical fibers is permanently attached to the optical ferrule, and the exposed cladding of the stripped portion is permanently attached to the optical fiber retainer.

[0002] In some aspects herein, an optical ferrule assembly configured for use in an optical connector is provided, the optical ferrule assembly including an optical ferrule, an optical fiber retainer, and a plurality of polarization-maintaining optical fibers. Each polarization-maintaining optical fiber has a core surrounded by a cladding and a cladding surrounded by a buffer. Each polarization-maintaining optical fiber is attached to the optical fiber retainer at a location away from a first fiber end of the polarization-maintaining optical fiber. The optical fiber retainer applies pressure to each location of the polarization-maintaining optical fiber such that the cladding of the polarization-maintaining optical fiber does not move within the retainer.

[0003] In some aspects herein, an optical ferrule assembly configured for use in an optical connector is provided, the optical ferrule assembly including an optical ferrule, an optical fiber retainer, and a plurality of polarization-maintaining optical fibers. Each polarization-maintaining optical fiber has a core surrounded by a cladding, and a cladding surrounded by a buffer. Each polarization-maintaining optical fiber is attached to the optical fiber retainer at a position spaced apart from a first fiber end of the polarization-maintaining optical fiber. The optical fiber retainer is configured to securely hold each of the polarization-maintaining optical fibers in position such that the cladding of the polarization-maintaining optical fiber does not move within the retainer. Each of the first fiber ends of the plurality of polarization-maintaining optical fibers is permanently attached to the optical ferrule. When light having the same first polarization is injected into each polarization-maintaining optical fiber, the output beam from each polarization-maintaining optical fiber has the same second polarization.

[0004] In some aspects herein, a method of manufacturing an optical ferrule assembly configured for use in an optical connector is provided, the method including providing a plurality of polarization-maintaining optical fibers, each having a core surrounded by a cladding and a cladding surrounded by a buffer. Stripping the buffer from each polarization-maintaining optical fiber away from a first fiber end of the polarization-maintaining optical fiber to form a stripped portion exposing the cladding, the stripped portion being disposed between the first and second non-stripped portions of the polarization-maintaining optical fiber. Positioning the plurality of polarization-maintaining optical fibers within an optical fiber retainer such that the stripped portions of the plurality of polarization-maintaining optical fibers are substantially contained within the optical fiber retainer, and rotating the polarization-maintaining optical fibers such that when light having the same first polarization is injected into each polarization-maintaining optical fiber, an output beam from each polarization-maintaining optical fiber has the same second polarization. While maintaining the rotational alignment of the polarization-maintaining optical fibers, an adhesive is applied to the stripped portions within the optical fiber retainer such that the claddings of the polarization-maintaining optical fibers are attached to the optical fiber retainer and prevented from moving relative to the retainer.

[0005] In some aspects herein, an optical assembly configured to be assembled to an optical ferrule is provided, the optical assembly including an optical fiber retainer and a plurality of polarization-maintaining optical fibers. Each polarization-maintaining optical fiber has a core surrounded by a cladding and a cladding surrounded by a buffer. The buffer is stripped away from a fiber end of the polarization-maintaining optical fiber to form a stripped portion exposing the cladding, the stripped portion being disposed between a first and a second non-stripped portion of the polarization-maintaining optical fiber. The first non-stripped portion extends from the stripped portion toward the fiber end of the polarization-maintaining optical fiber. The exposed cladding of the stripped portion is permanently attached to the optical fiber retainer.

[0006] In some embodiments herein, an optical assembly configured to be assembled to an optical ferrule is provided, the optical assembly including an optical fiber retainer and a plurality of polarization-maintaining optical fibers. Each polarization-maintaining optical fiber has a core surrounded by a cladding and a cladding surrounded by a buffer. Each polarization-maintaining optical fiber is attached to the optical fiber retainer at a position away from a first fiber end of the polarization-maintaining optical fiber. The optical fiber retainer is configured to securely hold each of the polarization-maintaining optical fibers in position such that the cladding of the polarization-maintaining optical fiber does not move within the retainer. When light having the same first polarization is injected into each polarization-maintaining optical fiber, the output beam from each polarization-maintaining optical fiber has the same second polarization. [Brief description of the drawings]

[0007] [Figure 1A] 1 shows a perspective view of a typical polarization-maintaining optical fiber in the prior art. [Figure 1B] 1 shows a perspective view of a typical polarization-maintaining optical fiber in the prior art. [Diagram 2] 1 illustrates an isometric view of an optical ferrule assembly according to an embodiment of the present disclosure. [Figure 3A] 1A-1C show end views of an optical fiber retainer before and after optical alignment of an optical fiber according to an embodiment of the present disclosure. [Figure 3B]1A-1C show end views of an optical fiber retainer before and after optical alignment of an optical fiber according to an embodiment of the present disclosure. [Figure 4] 1 illustrates an isometric view of a polarization-maintaining optical fiber in an optical fiber retainer, according to an embodiment of the present disclosure. [Diagram 5] 1 illustrates an isometric view of a polarization-maintaining optical fiber in an optical fiber retainer according to another embodiment of the present disclosure. [Figure 6] 1A-1C show diagrams illustrating how a polarization-maintaining optical fiber within a polarization-maintaining optical fiber retainer is bent as a "lever" to rotate the optical fiber, according to one embodiment of the present disclosure. [Figure 7A] 1A-1C show end views of an optical fiber retainer before and after optical alignment of the optical fiber, illustrating how the bending portion used to rotate the optical fiber rotates the optical fiber, according to one embodiment of the present disclosure. [Figure 7B] 1A-1C show end views of an optical fiber retainer before and after optical alignment of the optical fiber, illustrating how the bending portion used to rotate the optical fiber rotates the optical fiber, according to one embodiment of the present disclosure. [Figure 8] 1 illustrates an isometric view of an optical ferrule assembly including a connector housing according to an embodiment of the present disclosure. [Figure 9] 2 shows a flow chart detailing steps of a method for manufacturing an optical ferrule assembly according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] In the following description, reference is made to the accompanying drawings, which form a part hereof. In these drawings, various embodiments are shown by way of example. It should be noted that the drawings are not necessarily to scale. It is to be understood that other embodiments are contemplated and may be made without departing from the scope or spirit of the present specification. The following detailed description, therefore, is not to be taken in a limiting sense.

[0009] Some fiber optic connectors use an array of polarized or polarization-maintaining (PM) optical fibers, which require proper rotational alignment within the connector. For connectors that use expanding beam ferrules, this is most effectively done by aligning the fibers while attaching a fiber optic retainer (e.g., a collet) to the fiber array.

[0010] Photonic integrated circuits (PICs, e.g., silicon photonics PICs) are often designed to operate on a specific polarization of light in optical fiber. To maintain the polarization between PICs, or between a laser and a PIC, polarization-maintaining optical fiber is required, which may contain "stressed sections" (e.g., sections with different composition) to maintain the polarization state within the cladding of the fiber. Optical connectors using polarization-maintaining optical fiber need to control the rotational orientation of these fibers to achieve the desired coupling to the PIC.

[0011] The protective polymer buffer that surrounds the optical fiber is usually loosely attached to the glass cladding of the fiber, allowing the buffer to be easily peeled away from the fiber for splicing or connector installation, but this allows the glass fiber to rotate and / or "piston" within the buffer, making it difficult to maintain rotational alignment between the optical fibers when they are attached to an optical ferrule.

[0012] According to some aspects herein, an optical ferrule assembly includes a polarization-maintaining optical fiber that includes a small "stripped section" (e.g., 1 millimeter long) a distance from the end of the optical fiber that is to be attached to the optical ferrule. This stripped section is placed into an optical fiber retainer or collet and rotated until the fibers are optically aligned. In some embodiments, after rotational alignment of the fibers, an adhesive is applied to the stripped section through the optical fiber retainer to secure the exposed cladding of each optical fiber in place relative to the optical fiber retainer and "lock in" the aligned optical fibers before the open ends of the optical fibers are attached to the optical ferrule.

[0013] According to some aspects of the present disclosure, an optical ferrule assembly configured for use in an optical connector includes an optical ferrule, an optical fiber retainer, and a plurality of polarization-maintaining optical fibers. In some embodiments, each polarization-maintaining optical fiber includes a core (through which an optical signal propagates), a cladding, and a buffer. In some embodiments, the buffer is stripped away from a fiber end of the polarization-maintaining optical fiber to form a stripped portion that exposes the cladding. In some embodiments, the stripped portion is disposed between a first and a second non-stripped portion of the polarization-maintaining optical fiber. In some embodiments, the first non-stripped portion extends from the stripped portion toward a fiber end of the polarization-maintaining optical fiber (i.e., an end of the optical fiber that is connected to an optical component such as an optical ferrule). In some embodiments, each fiber end of the plurality of polarization-maintaining optical fibers is permanently attached to the optical ferrule, and the exposed cladding of the stripped portion is permanently attached to the optical fiber retainer.

[0014] In some embodiments, at least some of the optical fibers of the plurality of optical fibers are rotated before the exposed cladding is permanently attached to the optical fiber retainer. In some embodiments, the polarization axis of each polarization-maintaining optical fiber of the plurality of polarization-maintaining optical fibers are aligned to within 10 degrees, or within 8 degrees, or within 6 degrees, or within 4 degrees, or within 2 degrees, or within 1 degree of each other. In some embodiments, the polarization axis of at least one polarization-maintaining optical fiber is oriented at a predetermined angle within about 10 degrees relative to the fiber retainer. In some embodiments, the polarization axis of each polarization-maintaining optical fiber is oriented at a predetermined angle within 10 degrees relative to the fiber retainer.

[0015] In some embodiments, the optical ferrules of the optical ferrule assembly may be configured to be directly connected (i.e., not part of an optical connector, not disposed in a housing, not connected) and aligned with another optical component, such as a photonic integrated circuit (PIC). In other embodiments, the ferrules may be configured to be mounted in a cradle (i.e., socket) that is attached to the PIC. In some embodiments, the optical ferrule assembly further includes a housing (e.g., a housing of an optical connector), and the optical fiber retainer is configured to be mounted or assembled within the housing. In some embodiments, when the optical ferrule assembly is assembled to the housing, the optical fiber retainer is mounted within the housing and provides the only attachment of the optical ferrule assembly to the housing.

[0016] According to some aspects of the present disclosure, an optical ferrule assembly configured for use in an optical connector includes an optical ferrule, an optical fiber retainer, and a plurality of polarization-maintaining optical fibers. In some embodiments, each polarization-maintaining optical fiber has a core surrounded by a cladding and a cladding surrounded by a buffer. In some embodiments, each polarization-maintaining optical fiber is attached to the optical fiber retainer at a location away from a first fiber end of the polarization-maintaining optical fiber. In some embodiments, the optical fiber retainer applies pressure to each location of the polarization-maintaining optical fiber (e.g., mechanically captures and compresses the optical fiber) to prevent the cladding of the polarization-maintaining optical fiber from moving within the retainer.

[0017] In some embodiments, at least some of the optical fibers of the plurality of optical fibers may be rotated before the pressure is applied. For example, in some embodiments, each polarization-maintaining optical fiber of the plurality of polarization-maintaining optical fibers may be rotated to have approximately the same output polarization. In some embodiments, after the optical fibers are rotated and aligned, injecting light having the same first polarization into each polarization-maintaining optical fiber results in an output beam from each polarization-maintaining optical fiber having the same second polarization. In some embodiments, the polarization axis of at least one polarization-maintaining optical fiber may be oriented at a predetermined angle (or within 10 degrees of that angle) with respect to the fiber retainer. In some embodiments, the polarization axis of each polarization-maintaining optical fiber may be oriented at a predetermined angle (or within 10 degrees of that angle) with respect to the fiber retainer.

[0018] In some embodiments, the optical ferrule assembly further includes a housing (e.g., a housing of an optical connector), and the optical fiber retainer is configured to be mounted or assembled within the housing. In some embodiments, when the optical ferrule assembly is assembled to the housing, the optical fiber retainer is mounted within the housing and provides the only attachment of the optical ferrule assembly to the housing.

[0019] According to some aspects of the present disclosure, an optical ferrule assembly configured for use in an optical connector includes an optical ferrule, an optical fiber retainer, and a plurality of polarization-maintaining optical fibers. In some embodiments, each polarization-maintaining optical fiber includes a core surrounded by a cladding, and a cladding surrounded by a buffer. In some embodiments, each polarization-maintaining optical fiber is attached to the optical fiber retainer at a position away from a first fiber end of the polarization-maintaining optical fiber. In some embodiments, the optical fiber retainer is configured to securely hold each position of the polarization-maintaining optical fiber and prevent the cladding of the polarization-maintaining optical fiber from moving within the retainer (e.g., applying mechanical pressure to each fiber's buffer compresses the internal cladding and prevents movement). In some embodiments, each first fiber end of the plurality of polarization-maintaining optical fibers is permanently attached to the optical ferrule. In some embodiments, when light having the same first polarization is injected into each polarization-maintaining optical fiber, the output beam from each polarization-maintaining optical fiber has the same second polarization (e.g., each polarization-maintaining optical fiber is rotationally aligned).

[0020] In some embodiments, at least some of the optical fibers of the plurality of optical fibers may be rotated before applying pressure. For example, in some embodiments, each polarization-maintaining optical fiber of the plurality of polarization-maintaining optical fibers may be rotated to have approximately the same output polarization. In some embodiments, when light having the same first polarization is injected into each polarization-maintaining optical fiber, the output beam from each polarization-maintaining optical fiber has the same second polarization.

[0021] In some embodiments, the polarization axis of at least one polarization-maintaining optical fiber may be oriented at a predetermined angle within about 10 degrees relative to the fiber retainer. In some embodiments, the polarization axis of each polarization-maintaining optical fiber may be oriented at a predetermined angle within about 10 degrees relative to the fiber retainer.

[0022] In some embodiments, the optical ferrule assembly further includes a housing (e.g., a housing of an optical connector) and the optical fiber retainer is configured to be mounted or assembled within the housing. In some embodiments, when the optical ferrule assembly is assembled to the housing, the optical fiber retainer is mounted within the housing and provides a means of attachment for mounting the optical ferrule assembly to the housing.

[0023] According to some aspects of the present disclosure, a method of manufacturing an optical ferrule assembly configured for use in an optical connector includes the steps of: (a) providing a plurality of polarization-maintaining optical fibers, each having a core surrounded by a cladding, and the cladding surrounded by a buffer; (b) stripping the buffer from each polarization-maintaining optical fiber of the plurality of polarization-maintaining optical fibers away from a first fiber end of the polarization-maintaining optical fiber to form a stripped portion exposing the cladding, the stripped portion being disposed between the first and second non-striped portions of the polarization-maintaining optical fiber. (c) placing the plurality of polarization-maintaining optical fibers within the optical fiber retainer such that the stripped portions of the plurality of polarization-maintaining optical fibers are substantially contained within the optical fiber retainer; (d) Rotating the polarization-maintaining optical fibers such that when light having the same first polarization is injected into each polarization-maintaining optical fiber, the output beams from each polarization-maintaining optical fiber have the same second polarization. (e) while maintaining rotational alignment of the polarization-maintaining optical fiber, applying adhesive to the stripped portion within the optical fiber retainer to attach the cladding of the polarization-maintaining optical fiber to the optical fiber retainer and prevent the cladding from moving relative to the retainer.

[0024] In some embodiments, after the rotating step, the polarization axis of the at least one polarization-maintaining optical fiber may be oriented at a predetermined angle within about 10 degrees relative to the fiber retainer. In some embodiments, after the rotating step, the polarization axis of each polarization-maintaining optical fiber may be oriented at a predetermined angle within about 10 degrees relative to the fiber retainer. In some embodiments, the step of rotating the polarization-maintaining optical fiber may include observing an end of the polarization-maintaining optical fiber (i.e., evaluating a position of a stress feature in the cladding to see if the fiber is aligned in the direction of rotation).

[0025] In some embodiments, a method of manufacturing an optical ferrule assembly may include attaching an optical ferrule to a first end of a polarization-maintaining optical fiber after the polarization-maintaining optical fiber has been rotated and attached to an optical fiber retainer.

[0026] According to some aspects herein, an optical assembly configured for assembly to an optical ferrule includes an optical fiber retainer and a plurality of polarization-maintaining optical fibers. In some embodiments, each polarization-maintaining optical fiber has a core surrounded by a cladding and a cladding surrounded by a buffer. In some embodiments, the buffer is stripped away from a fiber end of the polarization-maintaining optical fiber to form a stripped portion (e.g., a 1 millimeter stripped portion) that exposes the cladding. In some embodiments, the stripped portion is disposed between a first and a second non-stripped portion of the polarization-maintaining optical fiber. In some embodiments, the first non-stripped portion extends from the stripped portion toward the fiber end of the polarization-maintaining optical fiber. In some embodiments, the exposed cladding of the stripped portion is permanently attached to the optical fiber retainer.

[0027] In some embodiments, at least some of the polarization-maintaining optical fibers of the plurality of polarization-maintaining optical fibers may be rotated before the exposed cladding is permanently attached to the optical fiber retainer. In some embodiments, the polarization axis of each polarization-maintaining optical fiber of the plurality of polarization-maintaining optical fibers may be aligned to within 10 degrees, 8 degrees, 6 degrees, 4 degrees, 2 degrees, or 1 degree of each other. In some embodiments, the polarization axis of at least one polarization-maintaining optical fiber may be oriented at a predetermined angle within about 10 degrees relative to the fiber retainer. In some embodiments, the polarization axis of each polarization-maintaining optical fiber may be oriented at a predetermined angle within about 10 degrees relative to the fiber retainer.

[0028] According to some aspects herein, an optical assembly configured for assembly into an optical ferrule includes an optical fiber retainer and a plurality of polarization-maintaining optical fibers. In some embodiments, each polarization-maintaining optical fiber includes a core surrounded by a cladding, and a cladding surrounded by a buffer. In some embodiments, each polarization-maintaining optical fiber is attached to the optical fiber retainer at a location away from a first fiber end of the polarization-maintaining optical fiber. In some embodiments, the optical fiber retainer is configured to securely hold each polarization-maintaining optical fiber (e.g., apply a "squeezing" mechanical pressure) so that the cladding of the polarization-maintaining optical fiber does not move within the retainer. In some embodiments, when light having the same first polarization is injected into each polarization-maintaining optical fiber, the output beam from each polarization-maintaining optical fiber has the same second polarization.

[0029] In some embodiments, at least some of the polarization-maintaining optical fibers of the plurality of polarization-maintaining optical fibers may be rotated before being securely held by the optical fiber retainer. In some embodiments, the polarization axis of each polarization-maintaining optical fiber of the plurality of polarization-maintaining optical fibers may be aligned within 10 degrees, 8 degrees, 6 degrees, 4 degrees, 2 degrees, or 1 degree of each other. In some embodiments, the polarization axis of at least one polarization-maintaining optical fiber may be oriented at a predetermined angle within about 10 degrees relative to the fiber retainer. In some embodiments, the polarization axis of each polarization-maintaining optical fiber may be oriented at a predetermined angle within about 10 degrees relative to the fiber retainer.

[0030] Referring to the drawings, Figures 1A and 1B show perspective views of a polarization-maintaining optical fiber in the prior art. Figure 1A shows a cross-section of a polarization-maintaining (PM) optical fiber 100. The PM optical fiber 100 includes a fiber core 14 surrounded by a cladding 10, which is further surrounded by a buffer 15. In some embodiments, the cladding 10 of the optical fiber 100 may include stressed sections 12, which are sections of different composition around or near the core 14, that help maintain the polarization state of light passing through the optical fiber 100. These stressed sections 12 function by intentionally introducing birefringence into the optical fiber, creating two well-defined polarization modes that propagate along the fiber.

[0031] There are several different designs that can be used to create the required birefringence in an optical fiber. Figure 1B shows three examples of such optical fibers. The examples in Figure 1B are for illustration only and not for limitation. In the example on the far left of Figure 1B, the stressed section 12a of the cladding 10a has a circular cross-section and is located on the opposite side of the core 14. This stressed section design is often referred to in the industry as PANDA (a name derived from the cross-section's resemblance to a panda's face and is also an acronym for "Polarization-maintaining AND Absorption-reducing"). Other common design examples include the elliptical cladding design shown in the center of Figure 1B, which has an elliptical stressed section 12b in the cladding 10b, and the "bowtie" design shown on the far right of Figure 1B, which has a stressed section 12c that looks like two halves of a bowtie in the cladding 10c.

[0032] 2 is an isometric view of an optical ferrule assembly according to one embodiment herein. In the optical ferrule assembly 400, a plurality of PM optical fibers 100 are held through an optical fiber retainer 200 (e.g., an optical fiber collet). In some embodiments, the optical fiber retainer 200 has an opening 205 to allow access to a section of the PM optical fiber 100. For example, as described herein, a stripped section of the PM optical fiber 100 (i.e., a portion where the buffer has been stripped to expose the cladding) is substantially contained within the optical fiber retainer 200, and an adhesive 70 can be applied to the stripped section of the PM optical fiber 100 through the opening 205 to prevent the cladding from moving back and forth or rotating within the buffer.

[0033] In some embodiments, the optical ferrule assembly 400 may include an optical ferrule 300 attached to the PM optical fiber 100 at a mounting location 305 on the end of the PM optical fiber 100. In some embodiments, the optical ferrule 300 is attached to the PM optical fiber 100 a predetermined distance D from the point where the optical fiber retainer 200 holds the PM optical fiber 100. In some embodiments, this distance D may be relatively short (e.g., within 5 mm, 10 mm, or 20 mm) such that rotation of the PM optical fiber 100, which is securely held by the optical fiber retainer 200, is substantially maintained at the mounting location 305 (i.e., there is not enough distance for the PM optical fiber 100 to rotate significantly relative to rotation at the optical fiber retainer 200).

[0034] 3A and 3B show end views of one embodiment of the optical fiber retainer 200 before and after optical alignment of the optical fibers, respectively. FIG. 3A shows an end view of the optical fiber retainer 200, showing the cross-sectional shape of the PM optical fiber 100 as it passes through the optical fiber retainer 200 (toward the optical ferrule 300, see FIG. 2). In the view of FIG. 3A, the relative orientation of the stress section 12 visible at the exposed end of the PM optical fiber 100 can be seen. Typically, the rotation of the PM optical fiber 100 is initially uncontrolled (i.e., some or all of the rotation of the PM optical fiber 100 is not aligned with the rotation of the other PM optical fibers 100, and the rotation of each PM optical fiber 100 is random, as shown in FIG. 3A).

[0035] Before the orientation of the PM optical fibers 100 can be "fixed" (e.g., by an adhesive applied through the optical fiber retainer 200, or by the optical fiber retainer 200 applying mechanical pressure to the PM optical fibers 100 to prevent rotation), the PM optical fibers 100 must be rotationally aligned. Figure 3B illustrates an embodiment in which the stressed sections 12 of each PM optical fiber 100 are substantially aligned (e.g., aligned in the same direction or rotational orientation, or aligned within 10 degrees of the same orientation).

[0036] 4 illustrates an isometric view of one embodiment of a polarization-maintaining optical fiber 100 within an optical fiber retainer 200. In this embodiment, the buffer 15 is removed from a portion of the PM optical fiber 100 to create a stripped portion 110 that exposes the cladding 10 of the PM optical fiber 100. In some embodiments, the stripped portion 110 is disposed between a first unstripped portion 130 and a second unstripped portion 140 of the PM optical fiber 100 and may be substantially contained within the optical fiber retainer 200 and exposed through an opening 205 in the optical fiber retainer 200. In some embodiments, the fiber end 120 of the PM optical fiber 100 can be observed (i.e., the stress section visible at the cross-sectional end of the cladding 10 of the fiber end 120; see also FIG. 3A ) to determine whether the stress section is rotationally aligned. As described herein, the PM optical fiber 100 can be rotated until the stress sections visible at the fiber end 120 are aligned, after which an adhesive (not shown in FIG. 4 ) can be applied to the stripped portion 110 through the opening 205 in the optical fiber retainer 200 to fix the rotational alignment and maintain the alignment before the fiber end 120 is permanently connected to an optical component (e.g., the optical ferrule 300 in FIG. 2 ).

[0037] FIG. 5 illustrates another embodiment of an optical fiber retainer 200a according to the present disclosure. In this embodiment, there is no stripped portion (such as stripped portion 110 shown in FIG. 4) on the PM optical fiber 100. Instead, the optical fiber retainer 200a is configured to apply mechanical pressure to the non-stripped portion of the PM optical fiber 100, preventing the buffer 15 of the PM optical fiber 100 from applying pressure to the internal cladding 10 and from rotating or "pistoning" (i.e., sliding back and forth) within the buffer 15. In some embodiments, for example, the optical fiber retainer 200a includes an upper section 220a and a lower section 220b that are pressed together to apply pressure to the PM optical fiber 100. In some embodiments, a clamping piece 215 is applied to the optical fiber retainer 200a to maintain the pressure of the upper section 220a and the lower section 220b on the PM optical fiber 100.

[0038] One example of a method for rotating each PM optical fiber 100 is shown in Figure 6. Figure 6 is for illustrative purposes only and is not limiting. Other suitable optical fiber rotation methods may be used. As shown in Figure 6, a section of each PM optical fiber 100 (which in this example includes individual fibers 100a, 100b, 100c, and 100d) can be bent upward to create a physical lever for rotating the individual fibers within optical fiber retainer 200 (shown here in dashed lines to illustrate the placement of PM optical fibers 100).

[0039] As shown in Figures 7A and 7B, the "lever arms" of the PM optical fibers 100 may be used. Figures 7A and 7B show end views of the optical fiber retainer 200 before and after optical alignment of the PM optical fibers 100, including a front view of the bent portion of the fiber used as the lever arm. Figure 7A shows the initial placement of the PM optical fibers 100 within the optical fiber retainer 200. In this initial configuration, the orientation of the stressed section 12 of each PM optical fiber 100 is random, and the bent lever arms of the PM optical fibers 100 extending behind the optical fiber retainer 200 are approximately parallel. Figure 7B shows an embodiment in which the lever arms of each fiber are individually rotated clockwise or counterclockwise until the stressed sections 12 of the PM optical fibers 100 are substantially aligned. In the example of Figure 7B, the lever arm of fiber 100a is rotated significantly clockwise, the lever arm of fiber 100b is rotated significantly counterclockwise, the lever arm of fiber 100c is rotated slightly clockwise, and the lever arm of fiber 100d is rotated slightly counterclockwise, such that the stressed sections 12 of each PM optical fiber 100 are substantially aligned. In some embodiments, a twist tool (not shown) may be used to grip each individual lever arm (e.g., to ensure rotational freedom of the lever arms at different distances behind the optical fiber retainer 200) to assist in the rotation of the PM optical fiber 100. After the fibers are permanently secured within the retainer, the twist tool can be removed and the lever arms released.

[0040] FIG. 8 shows an isometric view of one embodiment of an optical ferrule assembly including a connector housing. In some embodiments, the optical ferrule assembly 500 includes a connector housing 550, an optical fiber retainer 200, an optical ferrule 300, and a plurality of PM optical fibers 100. In some embodiments, the PM optical fiber 100 is held (and permanently attached) within the optical fiber retainer 200, which is attached to the optical ferrule 300 at the end of the PM optical fiber 100. In some embodiments, the optical fiber retainer 200 is attached to the connector housing 550. In some embodiments, the optical fiber retainer 200 is the only attachment point for the PM optical fiber 100 (i.e., in some embodiments, the optical ferrule 300 may be allowed to float within the connector housing 550). In other embodiments, such as the embodiment shown in FIG. 2, the optical ferrule assembly may be attached to an optical component (e.g., a PIC) without the connector housing 550.

[0041] 9 is a flow chart detailing steps in one embodiment of a method for manufacturing an optical ferrule assembly, including: Step 900 A plurality of polarization-maintaining optical fibers are provided, each having a core surrounded by a cladding, and the cladding surrounded by a buffer. Step 910 The buffer is stripped away from a first fiber end of the polarization-maintaining optical fiber to form a stripped portion exposing the cladding, the stripped portion being disposed between the first and second non-stripped portions of the polarization-maintaining optical fiber (see also FIG. 4). Step 920 The plurality of polarization-maintaining optical fibers are disposed within the optical fiber retainer such that the stripped portions of the plurality of polarization-maintaining optical fibers are substantially contained within the optical fiber retainer. Step 930.The polarization-maintaining optical fibers are rotated so that when light having the same first polarization is injected into each polarization-maintaining optical fiber, output beams having approximately the same second polarization are obtained (i.e., the PM optical fibers are approximately aligned in the direction of rotation or aligned within about 10 degrees). Step 940 While maintaining the rotational alignment of the PM optical fiber, adhesive is applied to the stripped portion within the optical fiber retainer to attach the cladding of the polarization-maintaining optical fiber to the optical fiber retainer and prevent it from moving (rotating or pistoning) relative to the retainer.

[0042] It should be noted that other embodiments are possible within the scope and spirit of the present specification. For example, with the optical fiber retainer 200a shown in Figure 5, the steps of peeling the PM optical fiber and applying adhesive to the optical fiber are not necessary. The optical fiber is held against rotation by the mechanical pressure applied by the optical fiber retainer 200a.

[0043] The term "about" is understood by those of ordinary skill in the art in the context in which it is used and described. When "about" describes a characteristic size, amount, or physical property as a quantity, if its use is not clear to those of ordinary skill in the art in the context, "about" is understood to mean within 10% of the specified value. A quantity using "about" as a specified value may be the exact specified value. For example, if not clear to those of ordinary skill in the art in the context, a quantity with a value of "about 1" means that the quantity has a value between 0.9 and 1.1, and may even be 1.

[0044] Terms such as "substantially" are understood by those of ordinary skill in the art in the context in which they are used and described. If the use of "substantially equal" is not clear to those of ordinary skill in the art in the context, "substantially equal" means approximately equal, similar to "about" above. If the use of "substantially parallel" is not clear to those of ordinary skill in the art in the context, "substantially parallel" means within 30 degrees of parallel. Directions or surfaces described as being substantially parallel may be within 20 degrees, or within 10 degrees, or parallel or nominally parallel in some embodiments. If the use of "substantially aligned" is not clear to those of ordinary skill in the art in the context, "substantially aligned" means aligned within 20% of the width of the objects being aligned. Objects described as being substantially aligned may be aligned within 10% or within 5% of the width of the objects being aligned in some embodiments.

[0045] All publications, patents, and patent applications cited above are incorporated herein by reference in their entirety in a consistent manner. In the event of any inconsistency or conflict between the cited publications and portions of this application, the information in the preceding description shall control.

[0046] Descriptions of elements in a figure should be understood to apply equally to corresponding elements in other figures unless otherwise indicated. Although specific embodiments have been illustrated and described herein, those skilled in the art will appreciate that various alternative and / or equivalent implementations for the specific embodiments illustrated and described may be substituted without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Accordingly, it is intended that the present disclosure be limited only by the claims and the equivalents thereof.

Claims

1. 1. An optical ferrule assembly configured for use in an optical connector, comprising: An optical ferrule; an optical fiber retainer; a plurality of polarization-maintaining optical fibers, each polarization-maintaining optical fiber having a core surrounded by a cladding and the cladding surrounded by a buffer, the buffer being stripped away from a fiber end of the polarization-maintaining optical fiber to form a stripped portion exposing the cladding, the stripped portion being disposed between first and second non-striped portions of the polarization-maintaining optical fiber, the first non-striped portion extending from the stripped portion toward the fiber end of the polarization-maintaining optical fiber, the fiber end being permanently attached to the optical ferrule, and the exposed cladding of the stripped portion being permanently attached to the optical fiber retainer. Optical ferrule assembly.

2. 2. The optical ferrule assembly of claim 1, wherein at least some of the optical fibers of the plurality of optical fibers are rotated before the exposed cladding in the stripped portion of at least some of the optical fibers of the plurality of optical fibers is permanently attached to the optical fiber retainer.

3. 2. The optical ferrule assembly of claim 1, wherein the polarization axes of each of the plurality of polarization-maintaining optical fibers are aligned within 10 degrees (or 8 degrees, 6 degrees, 4 degrees, 2 degrees, 1 degree) of one another.

4. 2. The optical ferrule assembly of claim 1, wherein a polarization axis of at least one of said plurality of polarization-maintaining optical fibers is oriented at a predetermined angle (or within 10 degrees of that angle) with respect to said fiber retainer.

5. 2. The optical ferrule assembly of claim 1, wherein a polarization axis of each of said plurality of polarization-maintaining optical fibers is oriented at a predetermined angle (or within 10 degrees of that angle) with respect to said fiber retainer.

6. The optical ferrule assembly of claim 1 further comprising a housing, the optical fiber retainer being configured to be mounted within the housing.

7. 7. The optical ferrule assembly of claim 6, wherein when the optical ferrule assembly is assembled to a housing, the optical fiber retainer is mounted within the housing and provides a sole attachment of the optical ferrule assembly to the housing.

8. 1. An optical ferrule assembly configured for use in an optical connector, comprising: An optical ferrule; an optical fiber retainer; and a plurality of polarization-maintaining optical fibers, each polarization-maintaining optical fiber having a core surrounded by a cladding and the cladding surrounded by a buffer, the polarization-maintaining optical fibers being attached to the optical fiber retainer at a position away from a first fiber end of the polarization-maintaining optical fiber, the optical fiber retainer applying pressure to each polarization-maintaining optical fiber at said position to prevent the cladding of the polarization-maintaining optical fiber from moving within the retainer.

9. 9. The optical ferrule assembly of claim 8, wherein at least some of the optical fibers of the plurality of optical fibers are rotated before pressure is applied to the at least some of the optical fibers.

10. 9. The optical ferrule assembly of claim 8, wherein each polarization-maintaining optical fiber of the plurality of polarization-maintaining optical fibers is rotated to have approximately the same output polarization.

11. 9. The optical ferrule assembly of claim 8, wherein injecting light having the same first polarization into each polarization-maintaining optical fiber results in an output beam from each polarization-maintaining optical fiber, each output beam having the same second polarization.

12. 9. The optical ferrule assembly of claim 8, wherein a polarization axis of at least one of the plurality of polarization-maintaining optical fibers is oriented at a predetermined angle (or within 10 degrees of that angle) with respect to the fiber retainer.

13. 9. The optical ferrule assembly of claim 8, wherein the polarization axis of each of the plurality of polarization-maintaining optical fibers is oriented at a predetermined angle (or within 10 degrees of that angle) with respect to the fiber retainer.

14. 9. The optical ferrule assembly of claim 8, further comprising a housing, the optical fiber retainer configured to be mounted within the housing.

15. 15. The optical ferrule assembly of claim 14, wherein the optical fiber retainer is attached to the housing when the optical ferrule assembly is assembled to the housing, providing a sole attachment of the optical ferrule assembly to the housing.

16. 1. An optical ferrule assembly configured for use in an optical connector, comprising: An optical ferrule; an optical fiber retainer; a plurality of polarization-maintaining optical fibers, each having a core surrounded by a cladding and the cladding surrounded by a buffer, attached to the optical fiber retainer at a location spaced from a first fiber end of the polarization-maintaining optical fiber, the optical fiber retainer configured to securely hold each polarization-maintaining optical fiber at said location such that the cladding of the polarization-maintaining optical fiber does not move within the retainer, and the first fiber end is permanently attached to the optical ferrule; An optical ferrule assembly, wherein injecting light having the same first polarization into each polarization-maintaining optical fiber results in an output beam from each polarization-maintaining optical fiber, each output beam having the same second polarization.

17. 17. The optical ferrule assembly of claim 16, wherein a polarization axis of at least one of the plurality of polarization-maintaining optical fibers is oriented at a predetermined angle (or within 10 degrees of that angle) with respect to the fiber retainer.

18. 17. The optical ferrule assembly of claim 16, wherein a polarization axis of each of the plurality of polarization-maintaining optical fibers is oriented at a predetermined angle (or within 10 degrees of that angle) with respect to the fiber retainer.

19. 17. The optical ferrule assembly of claim 16, further comprising a housing, the optical fiber retainer configured to be mounted within the housing.

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