Shared optical performance monitoring

• US 20060013585A1
• Filed: 07/15/2005
• Published: 01/19/2006
• Est. Priority Date: 07/15/2004
• Status: Active Grant

• Current Assignee: Lumentum Operations, LLC (Lumentum Holdings Inc.)
• Original Assignee: Metconnex Canada Inc.
• Inventors: Walklin, Sheldon, Ducellier, Thomas, Hnatiw, Alan
• Granted Patent: US 7,426,347 B2
• Time in Patent Office: Days
• US Class Current: 398/38
• CPC Class Codes: G01J 3/0213 using attenuators
• CPC Class Codes: G01J 3/28 Investigating the spectrum using colour filters G01J3/51
• CPC Class Codes: H04B 10/077 using a supervisory or additional signal
• CPC Class Codes: H04B 10/07955 Monitoring or measuring power
• CPC Class Codes: H04J 14/0212 using optical switches or wavelength selective switches [WSS]
• CPC Class Codes: H04J 14/0221 Power control, e.g. to keep the total optical power constant
• CPC Class Codes: H04J 14/0227 Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 2011/0016 using wavelength multiplexing or demultiplexing
• CPC Class Codes: H04Q 2011/0024 using space switching
• CPC Class Codes: H04Q 2011/0039 Electrical control
• CPC Class Codes: H04Q 2011/0049 Crosstalk reduction; Noise; Power budget
• CPC Class Codes: H04Q 2011/0083 Testing; Monitoring

Abstract

An apparatus for shared optical performance monitoring (OPM) is provided. A wavelength sensitive device receives light at an input port and routes it wavelength selectively to a set of output ports. To perform optical performance monitoring on the output ports, a monitoring component of each output signal is extracted, and these monitoring components are then combined. A single OPM function is then performed on the combined signal. However, with knowledge of the wavelengths that were included in each output signal, a virtual OPM function can be realized for each output port. The per port functionality can include total power per port, power per wavelength per port, variable optical attentuation, dynamic gain equalization, the latter two examples requiring feedback.

Claims

1. An optical monitoring apparatus comprising:

at least two optical monitoring input ports each to receive a respective set of incoming wavelengths;

an optical combiner to combine light received at the monitoring input ports into a combined monitoring signal;

a wavelength sensitive power monitoring device to determine a power measurement per wavelength of the combined monitoring signal; and

a power measurement processor adapted to process the power measurements to produce per-monitoring input port information.

2. The optical monitoring apparatus of claim 1 wherein the power measurement processor is adapted to determine a total power incoming from a particular monitoring input port according to a wavelength map of incoming wavelengths to this particular port with an assumption that the sets of incoming wavelengths are non-overlapping.

3. The optical monitoring apparatus of claim 2 further adapted to generate at least one feedback signal as a function of the total power determined for a given monitoring input.

4. The optical monitoring apparatus of claim 1 wherein the power measurement processor is adapted to determine a power per wavelength for each wavelength corresponding to a particular monitoring input port according to a wavelength map of incoming wavelengths to this particular port with an assumption that the sets of incoming wavelengths are non-overlapping.

5. The optical monitoring apparatus of claim 4 further adapted to generate at least one feedback signal as a function of the per wavelength power determined for a given monitoring input.

6. The optical monitoring apparatus of claim 1 wherein:

for at least one monitoring input port, the power measurement processor is adapted to determine a total power incoming from the monitoring input port according to a wavelength map of incoming wavelengths to the monitoring input port with an assumption that the sets of incoming wavelengths are non-overlapping; and

for at least one monitoring input port the power measurement processor is adapted to determine a power per wavelength for each wavelength corresponding to the monitoring input port according to a wavelength map of incoming wavelengths to the monitoring port with an assumption that the sets of incoming wavelengths are non-overlapping.

7. The optical monitoring apparatus of claim 1 wherein:

for at least one monitoring input port, the power measurement processor is adapted to determine a total power incoming from the monitoring input port according to a wavelength map of incoming wavelengths to the monitoring input port with an assumption that the sets of incoming wavelengths are non-overlapping, the optical monitoring apparatus further adapted to generate at least one feedback signal as a function of at least one of the total powers; and

for at least one monitoring input port the power measurement processor is adapted to determine a power per wavelength for each wavelength corresponding to the monitoring input port according to a wavelength map of incoming wavelengths to the monitoring port with an assumption that the sets of incoming wavelengths are non-overlapping, the optical monitoring apparatus further adapted to generate at least one feedback signal as a function of at least one of the per wavelength powers determined.

8. The optical monitoring apparatus of claim 1 wherein at least one of the optical monitoring input ports can be turned on and off.

9. The optical monitoring apparatus of claim 1 wherein the optical combiner applies a set of combiner'"'"'s ratios to signals received at the monitoring input ports, and the power measurement processor takes into account the combiner'"'"'s ratios in producing the per-monitoring input port information.

10. An apparatus comprising:

at least one input port, wherein a respective optical signal containing at least one wavelength is receivable at each input port;

a first wavelength sensitive device to separate the wavelengths received at the at least one input port into at least two output signals containing non-overlapping subsets of wavelengths;

an optical combiner to combine at least two of the output signals or monitoring components of at least two of the output signals to produce a monitoring signal; and

a wavelength sensitive power monitoring device optically connected to receive the monitoring signal.

11. The apparatus of claim 10 further comprising a self-test input for inputting a test signal to the wavelength sensitive device.

12. The apparatus of claim 11 further comprising a power measurement processor adapted to process the power measurements to produce per output signal information, and to generate feedback control signals as a function of the power measurements compared to known self-test input.

13. The apparatus of claim 11 further comprising a power measurement processor adapted to process the power measurements to produce per output signal information, and to perform calibration of the wavelength sensitive device as a function of the power measurements compared to known self-test input.

14. The apparatus of claim 10 further comprising:

a power measurement processor adapted to process power measurements to produce per output signal information.

15. The apparatus of claim 14 wherein the power measurement processor is adapted to determine a power per wavelength for each wavelength included in a particular output signal according to a wavelength map of incoming wavelengths to be included in that output signal.

16. The apparatus of claim 14 wherein the power measurement processor is adapted to determine a total power of a particular output signal according to a wavelength map of incoming wavelengths included in the particular output by summing power measurements of wavelengths included that output signal.

17. The apparatus of claim 14 wherein the optical combiner combines monitoring components of at least two of the output signals to produce the monitoring signal, the apparatus further comprising a respective tap coupler for extracting each monitoring component from each output signal.

18. The apparatus of claim 14 wherein the wavelength sensitive device comprises a wavelength selective switch.

19. The apparatus of claim 14 wherein the wavelength sensitive device comprises:

said at least one input port;

a respective optical port for each output signal;

for each optical port, a respective dispersive element optically connected to the optical port;

a bulk optical element having optical power;

a plurality of non-transmissive routing elements;

wherein for each wavelength channel;

the dispersive element of the input port and the bulk optical element disperses any light of the wavelength channel towards a respective one of said plurality of routing elements, and the respective one of said plurality of routing elements directs the light of the wavelength channel via the bulk optical element to a selected output port of said at least one output port via the respective dispersive element of the selected output port, the selected output port being determined by the respective routing element; and

wherein the optical combiner comprises a tap and continue arrangement for extracting and combining a monitoring component from each output signal.

20. The apparatus of claim 14 wherein the wavelength sensitive device comprises:

a wavelength selective switch adapted to couple an input signal from said input port to the output signals at a first plurality of output ports 1 to K with diffractive elements working at a main diffraction order and to couple the input signal to monitoring components at a second plurality of output ports l′

to K′

at another diffraction order with low efficiency, wherein the first set of output ports and the second set of output ports are arranged such that coupling from the input to the second output port i is related by a predetermined and fixed relationship to the coupling from the input to the corresponding first output port i for each given wavelength;

the optical combiner combining the monitoring components output by the wavelength sensitive switch.

21. The apparatus of claim 10 wherein the wavelength sensitive device comprises a reconfigurable add/drop multiplexer.

22. The apparatus of claim 10 wherein the wavelength sensitive device comprises a modular wavelength selective switch.

23. The apparatus of claim 22 wherein the modular wavelength selective switch comprises at least two wavelength selective switches having non-overlapping wavelength maps.

24. The apparatus of claim 10 wherein the wavelength sensitive device is adapted to attenuate each wavelength by a respective amount, the apparatus further comprising:

a control element adapted to feed back a control signal to the wavelength sensitive device to impose a predetermined attenuation profile with respect to wavelength for each output signal.

25. The apparatus of claim 10 wherein the wavelength sensitive device is adapted to attenuate each output signal by a respective amount, the apparatus further comprising:

a control element adapted to feedback a control signal to control the attenuation applied to each output signal.

26. The apparatus of claim 10 wherein said wavelength sensitive device comprises:

diffractive elements working at a main diffraction order to couple an input multi-wavelength signal to a plurality of output ports l to K with high efficiency;

a second set of output ports 1′

to K′

for outputting signals of another diffraction order with low efficiency, wherein signals output by the second set of output ports are combined by said optical combiner to produce the monitoring signal;

wherein the first set of output ports and the second set of output ports are arranged such that coupling from the input to the second output port i is related by a predetermined and fixed relationship to the coupling from the input to the corresponding first output port i for each given wavelength.

27. The apparatus of claim 10 wherein the optical combiner applies a set of combiner'"'"'s ratios in producing the monitoring signal, and the power measurement processor takes into account the combiner'"'"'s ratios when processing the power measurements to produce per output signal information.

28. The apparatus of claim 10 wherein the optical combiner has input ports for receiving signals from a wavelength selective switch comprising said wavelength sensitive device, and has at least one additional input port.

29. The apparatus claim 10 wherein the optical combiner comprises a tap and continue arrangement.

30. The apparatus claim 10 wherein the optical combiner is a distinct element connected to a plurality of optical taps.

31. The apparatus of claim 10 wherein the wavelength sensitive device comprises:

a wavelength selective switch and for at least one output port of the wavelength selective switch a respective further substantially linear optical processing element.

32. The apparatus of claim 31 wherein each substantially linear optical processing element is a gain element.

33. A tap and continue arrangement comprising:

a plurality of waveguides carrying signals to be monitored;

a crossing waveguide that crosses the plurality of waveguides so as to couple a small fraction of each signal to be monitored into the crossing waveguide.

34. The arrangement of claim 33 further comprising:

a wavelength sensitive power monitoring device connected to receive an output of the crossing waveguide to make per-wavelength power measurements.

35. The arrangement of claim 34 further comprising

a power measurement processor adapted to process the power measurements to produce information for each of said plurality of waveguides.

36. The arrangement of claim 35 wherein the power measurement processor is adapted to determine a total power incoming from each of the plurality of waveguides according to a wavelength map of incoming wavelengths to this particular waveguide with an assumption that the sets of incoming wavelengths are non-overlapping.

37. The arrangement of claim 35 wherein the power measurement processor is adapted to determine a power per wavelength for each wavelength corresponding to a particular waveguide of the plurality of waveguides according to a wavelength map of incoming wavelengths to this waveguide with an assumption that the sets of incoming wavelengths are non-overlapping.

38. An apparatus comprising:

a wavelength selective switch adapted to couple an input signal to a first plurality of output ports l to K with diffractive elements working at a main diffraction order and to couple the input signal to a second plurality of output ports l′

to K′

at another diffraction order with low efficiency, wherein the first set of output ports and the second set of output ports are arranged such that coupling from the input to the second output port i is related by a predetermined and fixed relationship to the coupling from the input to the corresponding first output port i for each given wavelength.

39. An apparatus comprising:

at least one first port and at least one second port;

a wavelength sensitive device operable in a first mode to route wavelengths of a signal received at the at least one first port to the at least one second port, and operable in a second mode to route wavelengths of a signal received at the at least one second port to the at least one first port;

directional optical taps on the at least one first port and the at least one second port configured such that in the first mode, monitoring component(s) are produced by the tap(s) on the at least one second port, and in the second mode the monitoring component(s) are produced by the tap(s) on the at least one first port;

an optical combiner to combine the monitoring components to produce a monitoring signal;

a wavelength sensitive power monitoring device optically connected to receive the overall monitoring signal.

40. A method of performing optical performance monitoring comprising:

receiving a plurality of monitoring components;

combining the monitoring components into a combined monitoring signal;

determining a power measurement per wavelength of the combined monitoring signal; and

processing the power measurements to produce per-monitoring component information.

41. The method of claim 40 wherein:

processing comprises determining a total power in particular monitoring component according to a wavelength map of incoming wavelengths to this particular monitoring component with an assumption that the sets of incoming wavelengths are non-overlapping.

42. The method of claim 41 further comprising:

generating at least one feedback signal as a function of the total power determined for a given monitoring component.

43. The method of claim 40 wherein processing comprises:

determining a power per wavelength for each wavelength corresponding to a particular monitoring component according to a wavelength map of incoming wavelengths to this particular monitoring component with an assumption that the sets of incoming wavelengths are non-overlapping.

44. The method of claim 43 further comprising:

generating at least one feedback signal as a function of the per wavelength power determined for a given monitoring component.

45. The method of claim 40 wherein processing comprises:

for at least one monitoring component, determining a total power incoming from the monitoring component according to a wavelength map of incoming wavelengths to the monitoring component with an assumption that the sets of incoming wavelengths are non-overlapping; and

for at least one monitoring component, determining a power per wavelength for each wavelength corresponding to the monitoring component according to a wavelength map of incoming wavelengths to the monitoring component with an assumption that the sets of incoming wavelengths are non-overlapping.

46. The method of claim 40 wherein:

for at least one monitoring component, determining a total power incoming from the monitoring component according to a wavelength map of incoming wavelengths to the monitoring component with an assumption that the sets of incoming wavelengths are non-overlapping, and generating at least one feedback signal as a function of at least one of the total powers; and

for at least one monitoring component, determining a power per wavelength for each wavelength corresponding to the monitoring component according to a wavelength map of incoming wavelengths to the monitoring port with an assumption that the sets of incoming wavelengths are non-overlapping, and generating at least one feedback signal as a function of at least one of the per wavelength powers determined.

47. The method of claim 40 wherein at least one of the optical monitoring components can be turned on and off.

48. The method of claim 40 wherein the combining comprises applying a set of combiner'"'"'s ratios to the monitoring components, and the processing takes into account the combiner'"'"'s ratios in producing the per-monitoring component information.