Shared OTDR resource

1 . An optical time domain reflectometer (OTDR) resource configured to be shared among a plurality of N individual optical fiber spans, comprising:

a 1×N optical switch; and

a pluggable OTDR element comprising an optical transmitter configured to produce an optical probe beam and a processor configured to control operation of the optical transmitter and the 1×N optical switch;

wherein an input path of the 1×N optical switch is coupled to an output port of the pluggable OTDR element;

wherein each one of a plurality of N separate output paths from the 1×N optical switch is coupled to a separate one of the plurality of N individual optical fiber spans; and

wherein the processor is configured to generate a fiber span selection control signal that causes the 1×N optical switch to couple a specific optical fiber span of the plurality of N individual optical fiber spans to the pluggable OTDR element for OTDR testing.

2 . The OTDR resource of claim 1 , wherein the 1×N optical switch comprises a discrete component coupled to the output port of the pluggable OTDR element.

3 . The OTDR resource of claim 1 , wherein the 1×N optical switch is integrated with the pluggable OTDR element and includes a signal path formed between the output port of the pluggable OTDR element and the input path of the 1×N optical switch.

4 . The OTDR resource of claim 1 , wherein the pluggable OTDR element comprises:

a first module housing electrical components and active optical components utilized in performing OTDR measurements; and

a second module housing passive optical components used for directing optical signals between the pluggable OTDR element and the specific optical fiber span of the plurality of N individual optical fiber spans under test.

5 . The OTDR resource of claim 4 , wherein the first module includes the processor utilized to control fiber span selection for OTDR testing.

6 . The OTDR resource of claim 4 , wherein:

the first module includes a photodetecting device;

the second module includes a three-port optical circulator having an input port responsive to the optical probe beam generated by the optical transmitter within the first module, a bi-directional optical port coupled to the input path of the 1×N optical switch, and an output port responsive to back reflections of the optical probe beam passing in a reverse direction through the 1×N optical switch; and

the output port of the three-port optical circulator directs the back reflections towards the photodetecting device in the first module.

7 . The OTDR resource of claim 6 , wherein the second module comprises a bandpass filter disposed in a signal path between the output port of the three-port optical circulator and the photodetecting device.

8 . The OTDR resource of claim 7 , wherein the bandpass filter comprises a wavelength tunable bandpass filter.

9 . The OTDR resource of claim 4 , wherein the 1×N optical switch is disposed within the second module.

10 . The OTDR resource of claim 1 , comprising

a plurality of N wavelength division multiplexers (WDMs); and

wherein each WDM is coupled between a separate output signal path of the 1×N optical switch and a separate optical fiber span of the plurality of N individual optical fiber spans.

11 . The OTDR resource of claim 1 , wherein the pluggable OTDR element comprises:

an active OTDR module including:

the optical transmitter configured to generate the optical probe beam;

an optical receiver configured to accept incoming reflected lightwaves associated with the optical probe beam; and

electrical process and control circuitry for energizing the optical transmitter and transforming received, reflected lightwaves into data useful in generating OTDR output traces; and

a passive OTDR module including:

a directional optical coupling device coupled to the active OTDR module and configured to direct propagation of the optical probe beam toward the specific optical fiber span under test and direct reflected lightwaves attributed to the optical probe beam into the active OTDR module.

12 . A pluggable optical time domain reflectometer (OTDR) element for OTDR testing a plurality of optical fiber spans, comprising:

an optical switch comprising a switch input path and a plurality of switch output paths to be coupled to ones of the plurality of optical fiber spans;

an optical transmitter configured to produce an optical probe beam; and

a processor configured to control operation of the optical switch and the optical transmitter;

wherein the switch input path is optically coupled to the optical transmitter to receive the optical probe beam;

wherein the optical switch is electrically coupled to the processor to receive a fiber span selection signal; and

wherein the processor, via generation of the fiber span selection signal, causes the optical switch to couple a specific one of the plurality of switch output paths and its associated optical fiber span to the switch input path so as to provide the associated optical fiber span with the optical probe beam for OTDR testing.

13 . The pluggable OTDR element of claim 12 , comprising:

an optical receiver; and

an optical circulator comprising:

an input port configured to receive the optical probe beam generated by the optical transmitter;

a bi-directional optical port configured to provide the optical probe beam to the switch input path and to receive back reflections of the optical probe beam passing in a reverse direction through the optical switch; and

an output port configured to direct the received back reflections to the optical receiver.

14 . The pluggable OTDR element of claim 13 , comprising a bandpass filter disposed between the output port of the optical circulator and the optical receiver.

15 . The pluggable OTDR element of claim 14 , wherein the bandpass filter comprises a wavelength tunable bandpass filter.

16 . The pluggable OTDR element of claim 12 , wherein the optical switch, the optical transmitter, and the processor are incorporated within a small form factor pluggable (SFP) module.