Search

EP-4388357-B1 - OPTICAL FIBER CONNECTOR FOR MINIMIZING SIGNAL TRANSMISSION LOSSES

EP4388357B1EP 4388357 B1EP4388357 B1EP 4388357B1EP-4388357-B1

Inventors

  • LEESON, KIM
  • TREZISE, SHAUN

Dates

Publication Date
20260506
Application Date
20220819

Claims (15)

  1. An optical fiber connector for achieving reduced signal transmission losses comprising: a ferrule basket portion (26) configured to hold a ferrule portion (24) and be disposed in one of a plurality of predetermined tuning positions; a carrier portion (28) configured to engage the ferrule basket portion (26); a polygonal biasing member (34) having a number of sides and configured to engage the ferrule basket portion (26) and the carrier portion (28), characterized in that the number of sides of the polygonal biasing member (34) determines a number of predetermined tuning positions of the ferrule portion (24), wherein the polygonal biasing member (34) is configured to engage the ferrule basket portion (26) and the carrier portion (28) so as to maintain the ferrule basket portion (26) at one of the plurality of predetermined tuning positions and mitigate against signal transmission losses between the ferrule portion (24) and a mating ferrule (24') when the ferrule basket portion (26) is at the one of the plurality of predetermined tuning positions.
  2. The optical fiber connector of claim 1, wherein the ferrule basket portion (26) comprises a ferrule assembly (22) having a ferrule (24) and a ferrule basket configured to hold the ferrule (24).
  3. The optical fiber connector of claim 2, wherein the carrier portion (28) comprises a carrier configured to hold the ferrule basket (26).
  4. The optical fiber connector of claim 3, wherein the polygonal biasing member (34) comprises a polygonal spring configured to be disposed between the ferrule basket and the carrier.
  5. The optical fiber connector of any of claims 1-4, wherein the polygonal biasing member (34) is configured to bias the ferrule basket portion (26) towards a front abutment surface (95) of the carrier portion (28) along a connector axis (44).
  6. The optical fiber connector of any of claims 1-5, wherein the ferrule basket portion (26) is configured to be disposed at a selected one of six predetermined tuning positions relative to the carrier.
  7. The optical fiber connector of any of claims 1-6, wherein the plurality of predetermined tuning positions comprises six predetermined tuning positions.
  8. The optical fiber connector of claim 1 in combination with claims 2-5 wherein the carrier (28) has a front sleeve (30) and a rear sleeve (56) configured to be rotationally fixed to the front sleeve (30), the polygonal spring configured to be rotationally fixed with the ferrule assembly (22), and rotationally fixed with the carrier (28), and wherein the carrier (28) is configured to be rotationally fixed relative to an inner housing and an outer housing of the optical fiber connector; wherein the polygonal spring (34) includes a rear portion (18) configured to be received in an engagement structure (36) defined by the rear sleeve (32) and a front portion (40) configured to be received on an engagement portion (42) of the ferrule basket (26); wherein the engagement structure (36) is configured to define a plurality of predetermined rotational positions constituting said predetermined tuning positions for tuning the connector; wherein the polygonal spring (34) is disposed at one of the plurality of predetermined rotational positions relative to the carrier (28); wherein the one of the plurality of predetermined rotational positions comprises a position selected to tune the optical fiber connector by optimizing a position of the ferrule (24) and a fiber terminated by the ferrule (24) relative to the carrier (28) to minimize signal loss when the ferrule (24) abuts a mating ferrule (24'); wherein the polygonal spring (34) is configured to maintain the ferrule (24) in the optimized position and to prevent rotation of the ferrule (24) relative to the carrier (28); and wherein the polygonal spring (34) is configured to permit the ferrule assembly (22) to float relative to the carrier (28) to optimize alignment of the ferrule (24) relative to the mating ferrule (24') when the ferrule (24) abuts the mating ferrule (24') so as to minimize signal transmission losses between the ferrule (24) and the mating ferrule (24').
  9. The optical fiber connector of claim 8, wherein the polygonal spring (34) is configured to be press fit into the engagement structure (36) and onto a stem portion (45) of the ferrule basket (26).
  10. The optical fiber connector of any of claims 8-9, wherein the engagement structure (36) comprises a polygonal bore and the engagement portion comprises a polygonal outer surface of the stem portion (45) of the ferrule basket (26).
  11. The optical fiber connector of claim 10, wherein each side (52) of the front portion (40) of the polygonal spring (34) is configured to be adjacent to a corresponding side (53) of the polygonal outer surface of the stem portion (45).
  12. The optical fiber connector of any of claims 8-11, wherein a rear end (60) of the polygonal spring (34) is configured to abut a forward facing surface of a flange (35) of the rear sleeve (32), and wherein a front end (62) of the polygonal spring (34) is configured to abut a rearward facing surface of the ferrule basket (26).
  13. The optical fiber connector of claim 8, wherein the inner housing (14) is configured to be disposed within the outer housing; the optical fiber connector further comprising a boot (16) configured to be affixed to a rearward portion of the outer housing; a connector subassembly (20) configured to be disposed within the inner housing (14) and including the ferrule assembly (22), the carrier (28) and the polygonal spring (34) wherein the engagement structure (36) comprises a hexagonal bore, the polygonal spring (34) comprises a hexagonal spring, and the engagement portion (42) comprises a hexagonal outer surface of a stem portion of the ferrule basket (26); wherein the plurality of predetermined rotational positions comprises six rotational positions; wherein the one of the plurality of predetermined rotational positions comprises a position selected to tune the connector by optimizing a position of the ferrule and a fiber terminated by the ferrule relative to the carrier to minimize signal loss when the ferrule abuts a mating ferrule; wherein the biasing member (34) is configured to maintain the ferrule (24) in the optimized position and to prevent rotation of the ferrule (24) relative to the carrier (28), the inner housing (14), and the outer housing (12).
  14. The optical fiber connector of claim 13, wherein each side of the front portion of the hexagonal spring is configured to be adjacent to a corresponding side of the hexagonal stem portion.
  15. The optical fiber connector of any of claims 13-14, wherein the front region (54) of the rear sleeve (56) defines the hexagonal bore.

Description

BACKGROUND The mechanical tolerances involved in terminating single mode optical fiber are much tighter than those for multimode optical fiber. Therefore, while it is quite common for multimode optical fiber be terminated at the point of use, for example, at a user's premises or at an outside junction box, in most product applications, single mode optical fiber is not terminated in the field. When single mode fiber must be terminated in the field, it can take a skilled technician between about 15 to 20 minutes to splice fibers together either by using a V-groove clamp or expensive fusion welding equipment. Single mode fiber is therefore often provided in a range of different lengths, pre-terminated at both ends with a connector plug ready to plug into a matching receptacle. Commonly, eight or twelve single mode optical fibers may be bundled together in an optical fiber cable having an outer protective tube inside of which the optical fibers run. An example of such a connector is the "Subscriber Connector," or SC connector, originally developed by NTT®. SC connectors have convenient push/pull style mating and are approximately square in cross-section and with a 2.5 mm diameter ferule at the termination of the optical fiber, surrounded by a plastic housing for protection. SC connectors are available in single or duplex configurations. The SC connector latches into a matching socket in a simple push motion. The push-pull design includes a spring against which the ferrule slides within a plastic inner housing. This arrangement provides a reliable contact pressure at the ferrule end and resists fiber end face contact damage of the optical fiber during connection. The connector can be quickly disconnected by disengaging a latch, before pulling the optical fiber connector from the socket. Until the latch is thus disengaged, the latch prevents withdrawal of the connector when the optical fiber cable is pulled in a direction away from the socket. Other examples of push/pull type connectors are LC connectors or MU connectors. Often, the end face of the ferrule is angled to reduce back reflections and this is usually described by adding APC (Angled Physical Contact) to the name. All such push/pull type optical fiber connectors are for convenience referred to herein as "SC-type" optical fiber connectors. SC-type LC or MU connectors are also known as small form factor connectors, by virtue of having a 1.5 mm diameter ferrule and a plastic housing. Signal losses within a system often occur within the connection between two optical fiber cores. For example, when the fiber is inserted into the ferrule, the core of a fiber may not and typically does not end up perfectly centered relative to the ferrule outer diameter due to manufacturing tolerances of the ferrule outer diameter to inner diameter concentricity, ferrule inner diameter hole size, fiber outer diameter, and fiber core to fiber outer diameter concentricity. If one or both of the fibers of mating connectors are off center when they are connected within an adapter, the fibers will not be aligned and thus there will be a signal loss when the signal is transmitted between the two fibers. It is therefore desirable to tune a connector to minimize this signal loss. Tuning can be accomplished by measuring signal characteristics through the connector and/or examining physical properties of the connector and then determining the optimal position of the ferrule and fiber in the connector. It may be desirable to provide an optical fiber connector having a tuned ferrule that can float when the ferrule engages with a mating ferrule in order to minizmize transmission losses. An example of optical fiber connector, disclosed by CN110609359A, includes a ferrule basket portion, a ferrule, and a cylindrical helical spring housed within a carrier portion. The biasing member is a cylindrical helical spring that allows for rotational movement between the components, preventing the ferrule from being locked in a fixed tuning position. In a second example, JPH1123905A discloses a multiple receptacle that accommodates both single-core and multi-core optical adapters. The multi-core adapter has a rectangular cylindrical housing with a locking mechanism to secure it in place, utilizing hooks and engagement holes. US2007/292084A1 discloses another example of an optical fiber connector of the prior art. SUMMARY An optical fiber connector is disclosed in any one of claims 1-15. BRIEF DESCRIPTION OF THE DRAWINGS Further advantages and features of the present disclosure will become apparent from the following description and the accompanying drawings, to which reference is made. In which are shown: FIG. 1A is an exploded perspective view of an exemplary fiber optic connector subassembly in accordance with various aspects of the disclosure.FIG. 1B is a perspective view of the fiber optic connector subassembly of FIG. 1A.FIG. 2 is a cross-sectional perspective view of a fiber optic connector inclu