REFLECTIVE TERMINATORS FOR OPTICAL NETWORKS AND METHODS OF MAKING THE SAME

Abstract

Optical terminators comprising a ferrule assembly with an optical filter for providing a reflective event in an optical network are disclosed. The optical filter assembly reflecting one or more preselected wavelengths so that the service provide can test optical links in an unmated connection node of the optical network. In one embodiment, the optical terminator has a hardened connector interface for outside plant applications. At least a portion of the optical filter assembly is disposed within the ferrule assembly of the optical terminator. The optical terminator advantageous allows the network operator to test and determine the operation of a branch of the optical network without having to send a technician to physically visit and test the operation of the desired link in the optical network.

Claims

1. A reflective terminator for optical networks, comprising: a ferrule assembly comprising an optical filter for reflecting one or more preselected wavelengths; a connector housing comprising a body, wherein the ferrule assembly is at least partially disposed within the connector housing, and the connector housing comprises a locking feature integrally formed into the body of the connector housing for securing the reflective terminator.

2. The reflective terminator of claim 1, wherein the body of the connector housing comprises a threaded portion.

3. The reflective terminator of claim 1, wherein the body of the connector housing comprises a keying portion.

4. The reflective terminator of claim 3, wherein the keying portion is a female keying portion.

5. The reflective terminator of claim 3, wherein the keying portion is arranged about 180 degrees from the locking feature.

6. The reflective terminator of claim 1, wherein the body of the connector housing comprises a threaded portion and a female keying portion, and the female keying portion extends into the threaded portion.

7. The reflective terminator of claim 1, wherein the locking feature comprises a ramp and a ledge.

8. The reflective terminator of claim 1, further comprising a SC outer housing.

9. The reflective terminator of claim 1, further comprising an outer housing and a coupling nut for converting the reflective terminator to a second connector footprint.

10. A reflective terminator for optical networks, comprising: a ferrule assembly comprising an optical filter for reflecting one or more preselected wavelengths; a connector housing, wherein the ferrule assembly is at least partially disposed within the connector housing; and an outer housing comprising a passageway and a plug end, the plug end comprising a hardened connector interface, wherein at least a portion of the connector housing is disposed within the passageway of the outer housing.

11. The reflective terminator of claim 10, wherein the plug end further comprises at least one opening extending from the plug end to a medial portion of the outer housing.

12. The reflective terminator of claim 10, wherein the plug end further comprises a first finger and a second finger.

13. The reflective terminator of claim 11, further comprising a body for securing the connector housing.

14. The reflective terminator of claim 11, further comprising a sealing element for sealing a rear end of the reflective terminator.

15. The reflective terminator of claim 11, wherein the outer housing is monolithically formed.

16. The reflective terminator of claim 11, wherein the outer housing is formed from a plurality of components.

17. The reflective terminator of claim 11, wherein the ferrule assembly has a first ferrule and a second ferrule.

18. The reflective terminator of claim 11, wherein the connector housing comprises a SC or LC connector footprint.

19. The reflective terminator of claim 11, wherein the optical filter comprises a thin film coating for reflecting the one or more preselected wavelengths.

20. The reflective terminator of claim 11, wherein the ferrule assembly comprises an optical waveguide having a Bragg grating.

21. The reflective terminator of claim 11, wherein the reflective terminator has a length of 100 millimeters or less.

22. The reflective terminator of claim 11, further comprising a coupling nut.

23. The reflective terminator of claim 11, further comprising an end cap.

24. The reflective terminator of claim 11, further comprising an end cap having a color code indicating the one or more preselected wavelengths for the reflective terminator.

25. The reflective terminator of claim 11, the one or more preselected wavelengths being selected from 1625 nanometers or 1650 nanometers.

26. The reflective terminator of claim 11, further comprising a wavelength marking indicia to identify the one or more preselected wavelengths.

27. The reflective terminator of claim 11, further comprising a dust cap.

28. The reflective terminator of claim 11, wherein the reflective terminal is a portion of an optical network.

29. A reflective terminator, comprising: a ferrule assembly comprising an optical filter for reflecting one or more preselected wavelengths; a connector housing, wherein the ferrule assembly is at least partially disposed within the connector housing; an outer housing comprising a passageway and a plug end, the plug end comprising a hardened connector interface, wherein at least a portion of the connector housing is disposed within the passageway of the outer housing; and a sealing element for sealing a rear end of the reflective terminator.

30. The reflective terminator of claim 29, wherein the plug end further comprises at least one opening extending from the plug end to a medial portion of the outer housing.

31. The reflective terminator of claim 29, wherein the plug end further comprises a first finger and a second finger.

32. The reflective terminator of claim 29, further comprising a body for securing the connector housing wherein a portion of the body fits within the outer housing.

33. The reflective terminator of claim 29, wherein the outer housing is monolithically formed.

34. The reflective terminator of claim 29, wherein the outer housing is formed from a plurality of components.

35. The reflective terminator of claim 29, wherein the ferrule assembly has a first ferrule and a second ferrule.

36. The reflective terminator of claim 29, wherein the connector housing comprises a SC or LC connector footprint.

37. The reflective terminator of claim 29, wherein the optical filter comprises a thin film coating for reflecting the one or more preselected wavelengths.

38. The reflective terminator of claim 29, wherein the ferrule assembly comprises an optical waveguide having a Bragg grating.

39. The reflective terminator of claim 29, wherein the reflective terminator has a length of 100 millimeters or less.

40. The reflective terminator of claim 29, further comprising a coupling nut.

41. The reflective terminator of claim 29, further comprising an end cap.

42. The reflective terminator of claim 29, further comprising an end cap having a color code indicating the one or more preselected wavelengths for the reflective terminator.

43. The reflective terminator of claim 29, the one or more preselected wavelengths being selected from 1625 nanometers or 1650 nanometers.

44. The reflective terminator of claim 29, further comprising a wavelength marking indicia to identify the one or more preselected wavelengths.

45. The reflective terminator of claim 29, further comprising a dust cap.

46. The reflective terminator of claim 29, wherein the reflective terminal is a portion of an optical network.

47. A reflective terminator, comprising: a ferrule assembly comprising an optical filter for reflecting one or more preselected wavelengths, wherein the optical filter comprises a thin film coating for reflecting one or more preselected wavelengths; a connector housing, wherein the ferrule assembly is at least partially disposed within the connector housing; an outer housing comprising a passageway and a plug end, the plug end comprising a hardened connector interface, wherein at least a portion of the connector housing is disposed within the passageway of the outer housing, and the plug end comprises at least one opening extending from the plug end to a medial portion of the outer housing, a first finger and a second finger; a sealing element for sealing a rear end of the reflective terminator; and a coupling nut disposed about a portion of the outer housing.

48. The reflective terminator of claim 47, wherein the outer housing is monolithically formed.

49. The reflective terminator of claim 47, wherein the outer housing is formed from a plurality of components.

50. The reflective terminator of claim 47, wherein the ferrule assembly has a first ferrule and a second ferrule.

51. The reflective terminator of claim 47, wherein the connector housing comprises a SC or LC connector footprint.

52. The reflective terminator of claim 47, wherein the optical filter comprises a thin film coating for the reflecting one or more preselected wavelengths.

53. The reflective terminator of claim 47, wherein the ferrule assembly comprises an optical waveguide having a Bragg grating.

54. The reflective terminator of claim 47, wherein the reflective terminator has a length of 100 millimeters or less.

55. The reflective terminator of claim 47, further comprising an end cap.

56. The reflective terminator of claim 47, further comprising an end cap having a color code indicating the one or more preselected wavelengths for the reflective terminator.

57. The reflective terminator of claim 47, the one or more preselected wavelengths being selected from 1625 nanometers or 1650 nanometers.

58. The reflective terminator of claim 47, further comprising a wavelength marking indicia to identify the one or more preselected wavelengths.

59. The reflective terminator of claim 47, further comprising a dust cap.

60. The reflective terminator of claim 47, wherein the reflective terminal is a portion of an optical network.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0015] FIGS. 1A-1C are prior art depictions showing various stages of mating of a preconnectorized cable having a plug connector with a receptacle;

[0016] FIG. 2 depicts a multiport having a reflective terminator disposed in one of the ports according to the concepts of the present application;

[0017] FIGS. 3A and 3B respectively show two different explanatory reflective terminators that reflect optical signals at two different wavelengths along with respective wavelength marking indicia on the reflective terminator for identification of the reflective wavelength;

[0018] FIG. 4 is a partially exploded view of the reflective terminator of FIG. 3A;

[0019] FIG. 5 is a perspective view of the connector assembly of FIG. 4 having a connector housing with a ferrule assembly with an optical filter for reflecting one or more preselected wavelengths;

[0020] FIG. 6 is a partially exploded view of the reflective assembly of FIG. 5;

[0021] FIG. 7 is a schematic view of the ferrule assembly of FIG. 6; and

[0022] FIGS. 8-15 are views showing the assembly of the reflective terminator of FIGS. 3A and 3B.

DETAILED DESCRIPTION

[0023] Reference will now be made in detail to the embodiments of the disclosure, examples of which are illustrated in the accompanying drawings. Whenever possible, like reference numbers will be used to refer to like components or parts.

[0024] The concepts for the reflective terminator described herein are suitable for creating optical reflective events at one or more predetermined wavelengths using an optical filter. Although, the reflective terminators disclosed are explained and depicted with a specific connector footprint the concepts may be used with other types of connector footprints such as a DLX connector footprint or the like. The concepts disclosed advantageously allow the placement of robust and reliable reflective terminator at connection nodes of an optical network in a removable, replaceable and scalable manner without a mated connection or having a dust cap on a connector node. The disclosed reflective terminators are useful for testing an optical network by sending an optical signal from the central office (i.e, an upstream location) to a network location having the reflective terminator and having an optical reflection return to the central office if the optical link is continuous.

[0025] Some of the concepts disclosed herein are explained with respect to well-known commercial solutions for Fiber-to-the-Home applications but are equally applicable to other architectures or applications. Specifically, the reflective terminator is explained in an embodiment for insertion into OptiTap receptacle, but the concepts disclosed herein may be used with other fiber optic connector interfaces hardened or not and are not limited to this particular optical connection. By way of explanatory example, other embodiments suitable for use with another connector form-factors such as a FASTConnect are possible.

[0026] FIG. 2 shows an explanatory environmental perspective view of reflective terminator 100 disclosed herein as a portion of an optical network, but the reflective terminator 100 may be used in other environments as well. Specifically, FIG. 2 depicts a multiport 1 having one or more receptacles 30 disposed through a wall of the multiport 1. Receptacles 30 are suitable for making optical connections with preconnectorized cables 10 having plug connector 5. However, when deployed in the field not all of the receptacles 30 may have a plug connector 5 mated with the respective receptacles 30, but the service provider may still have a need to test the optical network. The present application addresses this unresolved need by providing a reflective terminator 100 that may be disposed into an unmated receptacle 30, and still reflect a test signal upstream for testing purposes. As shown, reflective terminator 100 is disposed in one of the receptacles 30 ports for reflecting one or more preselected wavelengths upstream in the optical network for testing the operation of the network by the service provider according to the concepts disclosed. Reflective terminators according to the concepts disclosed are advantageous since testing may occur even though there is not a mated connection. Further, a quick visual inspection can determine that the reflective terminator is present without going up a ladder in aerial deployments, and buried applications are also easy to identify that a reflective terminator is present.

[0027] FIGS. 3A and 3B respectively show two different explanatory reflective terminators 100 that reflect optical signals at two different wavelengths. The concepts disclosed herein may be used with any suitable wavelength as desired. Reflective terminators 100 in FIGS. 3A and 3B are shown with dust cap 110 installed about a plug end PE of the device along with respective wavelength marking indicia MI on the rear end RE of the reflective terminator for identification of the reflective wavelength. Of course, other wavelength marking indicia MI are possible, but brightly colored wavelength marking indicia MI allow identification of the reflected wavelength of the device from a distance such as from the ground when the multiport is disposed on a pole in an aerial deployment.

[0028] FIG. 3A shows a reflective terminator 100 having an optical filter for reflecting an optical wavelength of 1625 nanometers, and FIG. 3B shows a reflective terminator 100 having an optical filter for reflecting an optical wavelength of 1650 nanometers. However, the concepts of the present application may be used with reflective terminators that reflect other suitable wavelengths as desired. Further, the optical filter may be any suitable type such as a high-pass, low-pass, bandpass, etc or construction such as a thin film coating, a grating on the fiber, etc.

[0029] When not in use, dust cap 110 is installed on the reflective terminator for protecting the interface of the device from dust, debris or damage. Specifically, dust cap 110 is attached to the coupling nut 170 as depicted in FIGS. 3A and 3B using any suitable structure. In this embodiment, dust cap 110 has a threaded portion that cooperates with a complimentary threads on coupling nut 170 (FIG. 4), but other suitable structures are possible. Specifically, coupling nut 170 is disposed about a portion of the outer housing 140 and may rotate with respect to the outer housing for securing the dust cap 110 or securing the reflective terminator 100 to receptacle 30 after the dust cap 110 is removed. Depending on the interface, coupling nut 170 may comprises a bayonet, threaded portion or the like for securing the reflective terminator 100 to a suitable port or receptacle 30 for aligning and mating the ferrule assembly 124 for reflecting optical signals.

[0030] FIG. 4 is a partially exploded view of the explanatory reflective terminator 100 depicted in FIG. 3A. Reflective terminator 100 comprises ferrule assembly 124, a connector housing 122 and outer housing 140. As shown in FIG. 7, the ferrule assembly 124 comprises an optical filter for reflecting one or more preselected wavelengths. The ferrule assembly 124 and connector housing 122 may be a portion of a connector assembly 120 as shown, but other constructions are possible. Reflective terminator may also comprise a body 130 for attaching connector assembly 120, a bushing 150 that fits into a rear opening of outer housing 140, a sealing element 160 such as a heat shrink for sealing the rear end of the outer housing 140, coupling nut 170 and an end cap 180. End cap 180 attaches at the rear end of the outer housing 140 and inhibits the coupling nut 170 from sliding off the outer housing 140.

[0031] Plug end PE of outer housing 140 has a similar connector interface as plug connector 5 for being received in receptacle 30 and mating with the SC connector inserted into the other end of the receptacle 30 so that the optical test signal may be reflected back upstream. Thus, optical filter creates a reflective event location in the optical network at the connection node, in this case, near receptacle 30 as shown in FIG. 2. Moreover, the reflective terminator 100 may be moved, added, or replaced at the connection node as desired by the network operator.

[0032] Reflective terminator 100 disclosed advantageously uses several of the components that are similar to the parts used for the OptiTap plug connector so that fewer new parts are needed, but this is not necessary.

[0033] Other constructions are possible for reflective terminator 100 using the concepts disclosed herein. For instance, the number of parts shown in FIG. 4 may be reduced by forming a plurality parts as a single part. By way of explanation, body 130, outer housing 140, bushing 150 and/or sealing element 160 may be formed as a single part. Likewise, the coupling nut 170 and end cap 180 may be formed as a single part, instead of separate parts. Other components may also function as the wavelength marking indicia. For instance, end cap 180 may have a colored code for identification of the preselected reflective wavelength of the device.

[0034] Outer housing 140 (or shroud) has a passageway between a plug end PE and a rear portion RP. Plug end PE comprises at least one opening 142 extending from the plug end PE to a medial portion of the outer housing 140. This allows the outer housing to cooperate with the adapter that is part of the receptacle 30 when mated. The plug end PE also comprises a first finger 144A and a second finger 144B for keying the orientation of the reflective terminator 100 with the receptacle 30. The first finger 144A and the second finger 144B have different cross-sectional shape for keying the orientation of the reflective terminator 100. Body 130 is keyed for insertion into the passageway of outer housing 140 in only one orientation. Body 130 secures the connector assembly 120 when assembled. Outer housing 140 may be monolithically formed or formed from a plurality of components as desired. Reflective terminator may have a relatively short length L such as 100 millimeters or less.

[0035] FIG. 5 is a perspective view of the connector assembly 120 of FIG. 4 and FIG. 6 is a partially exploded view of connector assembly 120. Connector assembly 120 comprises a connector housing 122 with a ferrule assembly 124 comprising an optical filter for reflecting one or more preselected wavelengths. Ferrule assembly 124 reflects one or more preselected optical wavelengths back to the head end of the optical network for testing the optical link. The preselected wavelengths that pass could having any suitable pass band required by the service provider. By way of non-limiting example, the ferrule assembly 110 may be suitable for passing 1310 nanometers (nm) and 1550 nm wavelength ranges and reflecting wavelengths in the 1625 nm range, but this is not necessary since there is no downstream connection. Consequently, the service operator can test the optical link to the connection node having reflective terminator 100 using a wavelength in the 1625 nm range that reflects back. Reflective terminator 100 may reflect one or more predetermined wavelengths by using any suitable structure such as a Bragg grating on an optical waveguide of the device or a thin film coating.

[0036] In this embodiment, connector housing 122 has a SC form-factor, but other form-factors are possible for the connector housing with other connector interfaces such as a LC form-factor. Connector assembly 120 may also comprise a resilient member 125 such as a coil spring to bias ferrule assembly to a forward position, and a spring push 128. As shown in FIG. 5, the ferrule assembly 124 is at least partially disposed within the connector housing 122.

[0037] FIG. 7 is a schematic view of the explanatory ferrule assembly 124 of FIG. 6, and other constructions of ferrule assemblies comprising an optical filter are possible. As best shown in FIGS. 6 and 7, ferrule assembly 124 comprises a first end 125 and a second end 127. The first end 125 comprises a first ferrule 124b having an end face and a second end 127 comprising a second ferrule 124e comprising an end face. The ferrule assembly 124 also comprises a ferrule holder 124d for securing the first ferrule 124b and the second ferrule 124e. As best depicted in FIG. 6, a key 128 is disposed on the ferrule holder 124d. First ferrule 124b secures an optical fiber 124a that is in optical communication with an optical filter 124c as shown. In this embodiment, the optical filter 124b comprises a thin film coating for reflecting one or more preselected wavelengths such as 1625 nanometers. In other embodiments, other ferrule assemblies may have the optical filter formed by an optical fiber comprising a Bragg grating, but still other constructions are possible for the optical filter.

[0038] FIGS. 8-15 are views showing explanatory steps for the assembly of the reflective terminator 100. FIG. 8 depicts connector assembly 120 being secured to the body 130. In this configuration, body 130 has latch arms LA disposed on the plug end side for securing the connector assembly 120 thereto to form a body sub-assembly. As shown, connector assembly 120 includes a dust cap on first ferrule 124b for protecting the same. FIG. 9 shows the body sub-assembly being inserted and aligned with the passageway of the outer housing 140 in the proper orientation from the plug end PE of the outer housing 140 before securing the same. FIG. 10 depicts a plunger tool used for seating the body sub-assembly within the outer housing 140, but the use of a plunger tool is not necessary. The body sub-assembly may have a suitable friction or slight interference fit for seating the same or may have a snap-fit geometry as desired. FIG. 11 shows the body sub-assembly fully seated within the passageway of the outer housing 140 with a portion of the body sub-assembly extending beyond the rear portion RP of the outer housing 140. Then bushing 150 may be attached at the rear portion RP of the outer housing 140 if used.

[0039] FIG. 12 shows the sealing element 160 attached to the rear portion RP of the outer housing 140. In this embodiment, the sealing element is a heat shrink, but other components may be used such as a cap with adhesive for sealing. FIG. 13 shows the coupling nut 170 being slid onto the outer housing 140 from the rear portion RP with the threaded portion of the coupling nut 170 facing the plug end PE. Then, end cap 180 is secured to the outer housing 140 for capturing the coupling nut 140, but still allowing rotation of the coupling nut 140 as shown in FIG. 14. In this embodiment, the end cap 180 has a color code (i.e., blue wavelength marking indicia) indicating the preselected wavelength for the reflective terminal. As shown, the reflective terminator 100 comprises a plug end PE with the connector interface for mating with receptacle 30 and the rear end RE has the color coding. Other wavelength marking indicia are possible to increase visibility. By way of example, FIG. 15 shows a plastic color-coded cap attached to the rear end RE of the reflective terminator to improve visibility for aerial deployments. Reflective terminator 100 may also comprise one or more O-rings for sealing. FIG. 15 shows an O-ring 179 disposed within a groove 178 of housing 170. In this embodiment, reflective terminator 100 is suitable for outside plant applications (i.e., outdoor applications); however, the concepts disclosed may be used in any suitable environment.

[0040] Outer housings 140 or the body 130 of reflector terminators may be formed from one or more components depending on the design and requirements for the device. In this particular embodiment, outer housing 140 is monolithically formed; however, other embodiments could have designs where the housings were formed from a plurality of components. Outer housing 140 or body 130 having a plurality of components could be assembled by snap-fitting, adhesive, welding or the like. Outer housing 140 may comprise one or more features for alignment during mating and may also comprise other features for securing the device. In other embodiments, the body 130 having the features for securing the connector assembly 120 may be integrally formed with the outer housing 140 to eliminate the body and reduce the part count for the reflective terminator.

[0041] Generally speaking, other than the connector assembly 120 and sealing element 160 most of the components of the reflective terminator 100 may be formed from a suitable polymer, but other materials such as metal are possible. In one example, the polymer is a UV stabilized polymer such as ULTEM 2210 available from GE Plastics if the component is exposed to the elements; however, other suitable polymer materials are possible. For instance, stainless steel or any other suitable metal may be used for various components as desired.

[0042] Although the disclosure has been illustrated and described herein with reference to explanatory embodiments and specific examples thereof, it will be readily apparent to those of ordinary skill in the art that other embodiments and examples can perform similar functions and/or achieve like results. All such equivalent embodiments and examples are within the spirit and scope of the disclosure and are intended to be covered by the appended claims. It will also be apparent to those skilled in the art that various modifications and variations can be made to the concepts disclosed without departing from the spirit and scope of the same. Thus, it is intended that the present application cover the modifications and variations provided they come within the scope of the appended claims and their equivalents.