Apparatus and method for testing fibers in a PON
View Patent ↗A manner of providing for testing of access fibers in a PON (passive optical network) using OTDR (optical time-domain reflectometry). According to the invention, a PON includes an optical splitter module having one or more optical couplers that combines downstream light from 1×N optical splitter directing the output of an OLT (optical line terminal) and a cyclic AWG (arrayed waveguide grating) for transmission toward one or more ONUs (optical network units). The splitter module is preferably formed on a single semiconductor chip, such as a PIC (photonic integrated circuit) chip and may reside in an outside plant of the PON.
1. A splitter module for a PON (passive optical network), comprising:
an optical splitter;
an OTDR transmitter comprising a light source
a cyclic AWG (arrayed waveguide grating); and
at least one WDM coupler for optically coupling an optical splitter communication link and a cyclic AWG communication link, wherein the at least one WDM coupler is situated downstream of both the optical splitter and the cyclic AWG.
2. The splitter module of claim 1 , further comprising a feeder-side WDM coupler situated upstream of both the optical splitter and the cyclic AWG for distributing light propagated along a feeder fiber to the optical splitter and the cyclic AWG.
3. The splitter module of claim 1 , wherein the light source is tunable to emit light of a plurality of wavelengths.
4. The splitter module of claim 3 , wherein the plurality of wavelengths are selected to be different from those wavelengths used in the PON for non-OTDR transmissions.
5. The splitter module of claim 3 , wherein the plurality of wavelengths are each greater than 1600 nm.
6. The splitter module of claim 3 , wherein the light source is a tunable laser.
7. The splitter module of claim 6 , wherein the tunable laser is tunable using temperature control.
8. The splitter module of claim 1 , further comprising an OTDR detection module comprising at least one photo detector.
9. The splitter module of claim 8 , wherein the at least one photo detector comprises a multi-modal photo detector.
10. The splitter module of claim 9 , wherein the at least one photo detector is a single multi-modal photo detector.
11. The splitter module of claim 8 , further comprising at least one optical tap for capturing OTDR reflections and providing them to the OTDR detection module.
12. The splitter module of
claim 1 further comprising a coupler linked to both the OTDR transmitter and the OTDR reflector and situated between them and the cyclic AWG.
13. The splitter module of claim 1 , wherein the optical splitter, the cyclic AWG, and the at least one WDM coupler are formed on a single semiconductor chip.
14. The splitter module of claim 13 , wherein the semiconductor chip is a PIC.
15. A PON, comprising:
an OLT
an OTDR transmitter;
an OTDR detector; and
a splitter module comprising:
an optical splitter;
a cyclic AWG; and
at least one WDM coupler situated between the optical splitter and an access fiber of the PON;
wherein the OTDR detector, the optical splitter, the cyclic AWG, and the at least one WDM coupler are formed on a single semiconductor chip.
16. The PON of claim 15 , wherein the OTDR transmitter is co-located with the OLT in a CO.
17. The PON of claim 15 , wherein the OTDR detector is co-located with the OLT in a CO.
18. The PON of claim 15 , wherein the splitter module is located in an outside plant.
19. The PON of claim 18 , wherein the OTDR transmitter is located in the outside plant.
20. The PON of claim 18 , wherein the OTDR detector is located in the outside plant.