Fiber optic dense wavelength division multiplexer utilizing a multi-stage parallel cascade method of wavelength separation

• US 6,263,126 B1
• Filed: 08/06/1998
• Issued: 07/17/2001
• Est. Priority Date: 08/06/1998
• Status: Expired due to Term

• Current Assignee: II-VI Delaware, Inc. (Coherent Corp.)
• Original Assignee: Avanex Corporation (Lumentum Holdings Inc.)
• Inventors: Cao, Simon X. F.
• Primary Examiner(s): NGO, HUNG NHAT
• Application Number:
  US09/130,386
• Time in Patent Office: 1,076 Days
• Field of Search: 385/33, 385/24, 385/45, 385/46, 385/36, 359/131
• US Class Current: 385/24
• CPC Class Codes: G02B 6/29349 Michelson or Michelson/Gires-Tournois configuration, i.e. based on splitting and interferometrically combining relatively delayed signals at a single beamsplitter
• CPC Class Codes: G02B 6/29383 Adding and dropping
• CPC Class Codes: G02B 6/29386 Interleaving or deinterleaving, i.e. separating or mixing subsets of optical signals, e.g. combining even and odd channels into a single optical signal

Abstract

An improved dense wavelength division multiplexer for the separation of optical channels is provided. The dense wavelength division multiplexer includes the inputting of an optical signal with the optical signal containing a plurality of optical channels; the separating of one or more of the plurality of optical channels from the optical signal using separators at least partly arranged in a multi-stage parallel cascade configuration; and the outputting of the separated plurality of channels along a plurality of optical paths. The dense wavelength division multiplexer of the present invention provides for a lower insertion loss by requiring an optical signal to travel through fewer optical components in the separation process.

Claims

1. A method for separating an optical signal into optical channels, the method comprising the steps of:

(a) inputting the optical signal, the optical signal comprising a plurality of optical channels;

(b) separating one or more of the plurality of optical channels from the optical signal using a plurality of separators, wherein at least one of the plurality of separators is configured as a 2×

2 switch, wherein the separators are at least partly arranged in a multi-stage parallel cascade configuration; and

(c) outputting the separated plurality of channels along a plurality of optical paths.

2. The method of claim 1, wherein the separators of the separating step (b) are arranged completely in a multi-stage parallel cascade configuration.

3. The method of claim 2, wherein the multi-stage parallel cascade configuration comprises:

a plurality of cascades occurring in parallel, wherein each cascade comprises some of the plurality of separators arranged in at least one stage, wherein each separator derives from or acts upon a product of a preceding stage.

4. The method of claim 1, wherein the separators of the separating step (b) are arranged in a hybrid parallel-serial cascade configuration.

5. The method of claim 4, wherein the hybrid parallel-serial cascade configuration comprises:

a plurality of cascades occurring in parallel, wherein each cascade comprises some of the plurality of separators arranged in a plurality of stages,

wherein a first stage of the plurality of stages of one of the plurality of cascades is arranged in a parallel cascade configuration, wherein each of the separators in the first stage derives from or acts upon a product of a preceding stage,

wherein a second stage of the plurality of stages of the one of the plurality of cascades is arranged in a serial cascade configuration, wherein the second stage is optically coupled to the first stage, wherein the separators in the second stage are optically coupled in series.

6. The method of claim 1, wherein the separators of the separating step (b) are arranged in a programmable router configuration.

7. The method of claim 6, wherein the programmable router configuration comprises:

the plurality of separators configured in either a multi-stage parallel cascade configuration or a hybrid parallel-serial cascade configuration, wherein at least one of the plurality of separators may be programmed such that a particular channel of the plurality of channels is routed to a particular optical path of the plurality of optical paths.

8. The method of claim 7, wherein the multi-stage parallel cascade configuration comprises:

a plurality of cascades occurring in parallel, wherein each cascade comprises some of the plurality of separators arranged in at least one stage, wherein each separator derives from or acts upon a product of a preceding stage.

9. The method of claim 7, wherein the hybrid parallel-serial cascade configuration comprises:

a plurality of cascades occurring in parallel, wherein each cascade comprises some of the plurality of separators arranged in a plurality of stages,

wherein a first stage of the plurality of stages of one of the plurality of cascades is arranged in a parallel cascade configuration, wherein each of the separators in the first stage derives from or acts upon a product of a preceding stage,

wherein a second stage of the plurality of stages of the one of the plurality of cascades is arranged in a serial cascade configuration, wherein the second stage is optically coupled to the first stage, wherein the separators in the second stage are optically coupled in series.

10. The method of claim 1, wherein the separators of the separating step (b) are arranged in a programmable configuration performing the add/drop function.

11. The method of claim 1, wherein the optical signal in step (b) is separated into a set of odd optical channels and a set of even optical signals.

12. The method of claim 1, wherein the separator comprises:

(a) a first glass block coupled to a second glass block, wherein the first glass block is optically coupled to the inputted optical signal;

(b) at least one reflective coating residing between the first and second glass blocks; and

(c) a split beam interferometer optically coupled to the first and second glass blocks, wherein the interferometer introduces a phase difference between at least two of the plurality of optical channels.

13. The method of claim 1, wherein the separator comprises:

(a) at least one lens optically coupled to the inputted optical signal;

(b) at least one lens optically coupled to the outputted plurality of optical channels;

(c) a polarization beam splitter optically coupled to the lenses; and

(d) at least two reflection interferometers optically coupled to the polarization beam splitter, wherein the interferometers introduce a phase difference between at least two of the plurality of optical channels.

28. The method of claim 10, wherein the programmable configuration performing the add/drop function comprises:

a first separator, comprising;

a first input port of the first separator,

a second input port of the first separator,

a first output port of the first separator, and

a second output port of the first separator; and

a second separator, comprising;

a first input port of the second separator optically coupled to the second output port of the first separator,

a second input port of the second separator,

a first output port of the second separator optically coupled to the second input port of the first separator, and

a second output port of the second separator.

14. A system for separating an optical signal into optical channels, the system comprising:

means for inputting the optical signal, the optical signal comprising a plurality of optical channels;

means for separating one or more of the plurality of optical channels from the optical signal, wherein the separating means is at least partly arranged in a multi-stage parallel cascade configuration, wherein the separating means comprises at least one 2×

2 switch; and

means for outputting the separated plurality of channels along a plurality of optical paths.

15. The system of claim 14, wherein the separators of the separating means are arranged completely in a multi-stage parallel cascade configuration.

16. The system of claim 15, wherein the multi-stage parallel cascade configuration comprises:

a plurality of cascades occurring in parallel, wherein each cascade comprises some the separators of the separating means arranged in at least one stage, wherein each separator derives from or acts upon a product of a preceding stage.

17. The system of claim 14, wherein the separators of the separating means are arranged in a hybrid parallel-serial cascade configuration.

18. The system of claim 17, wherein the hybrid parallel-serial cascade configuration comprises:

a plurality of cascades occurring in parallel, wherein each cascade comprises some of the separators of the separating means arranged in a plurality of stages,

wherein a first stage of the plurality of stages of one of the plurality of cascades is arranged in a parallel cascade configuration, wherein each of the separators in the first stage derives from or acts upon a product of a preceding stage,

wherein a second stage of the plurality of stages of the one of the plurality of cascades is arranged in a serial cascade configuration, wherein the second stage is optically coupled to the first stage, wherein the separators in the second stage are optically coupled in series.

19. The system of claim 14, wherein the separators of the separating means are arranged in a programmable router configuration.

20. The system of claim 19, wherein the programmable router configuration comprises:

the separators of the separating means configured in either a multi-stage parallel cascade configuration or a hybrid parallel-serial cascade configuration, wherein at least one of the separators may be programmed such that a particular channel of the plurality of channels is routed to a particular optical path of the plurality of optical paths.

21. The system of claim 20, wherein the multi-stage parallel cascade configuration comprises:

a plurality of cascades occurring in parallel, wherein each cascade comprises some of the separators of the separating means arranged in at least one stage, wherein each separator derives from or acts upon a product of a preceding stage.

22. The system of claim 20, wherein the hybrid parallel-serial cascade configuration comprises:

a plurality of cascades occurring in parallel, wherein each cascade comprises some of the separators of the separating means arranged in a plurality of stages,

wherein a first stage of the plurality of stages of one of the plurality of cascades is arranged in a parallel cascade configuration, wherein each of the separators in the first stage derives from or acts upon a product of a preceding stage,

wherein a second stage of the plurality of stages of the one of the plurality of cascades is arranged in a serial cascade configuration, wherein the second stage is optically coupled to the first stage, wherein the separators in the second stage are optically coupled in series.

23. The system of claim 14, wherein the separators of the separating means are arranged in a programmable configuration performing the add/drop function.

24. The system of claim 23, wherein the programmable configuration performing the add/drop function comprises:

a first separator, comprising;

a first input port of the first separator,

a second input port of the first separator,

a first output port of the first separator, and

a second output port of the first separator; and

a second separator, comprising;

a first input port of the second separator optically coupled to the second output port of the first separator,

a second input port of the second separator,

a first output port of the second separator optically coupled to the second input port of the first separator, and

a second output port of the second separator.

25. The system of claim 14, wherein the optical signal in the separating means is separated into a set of odd optical channels and a set of even optical signals.

26. The system of claim 14, wherein the separating means comprises:

(a) a first glass block coupled to a second glass block, wherein the first glass block is optically coupled to the inputting means;

(b) at least one reflective coating residing between the first and second glass blocks; and

(c) a split beam interferometer optically coupled to the first and second glass blocks, wherein the interferometer introduces a phase difference between at least two of the plurality of optical channels.

27. The system of claim 14, wherein the separating means comprises:

(a) at least one lens optically coupled to the inputting means;

(b) at least one lens optically coupled to the outputting means;

(c) a polarization beam splitter optically coupled to the lenses; and

(d) at least two reflection interferometers optically coupled to the polarization beam splitter, wherein the interferometers introduce a phase difference between at least two of the plurality of optical channels.

29. A method for separating an optical signal into optical channels, the method comprising the steps of:

(a) inputting the optical signal, the optical signal comprising a plurality of optical channels;

(b) separating one or more of the plurality of optical channels from the optical signal using a plurality of separators, wherein the separators are at least partly arranged in a multi-stage parallel cascade configuration, wherein at least one separator comprises;

a first glass block coupled to a second glass block, wherein the first glass block is optically coupled to the inputted optical signal,

at least one reflective coating residing between the first and second glass blocks, and

a split beam interferometer optically coupled to the first and second glass blocks, wherein the interferometer introduces a phase difference between at least two of the plurality of optical channels; and

(c) outputting the separated plurality of channels along a plurality of optical paths.

30. A method for separating an optical signal into optical channels, the method comprising the steps of:

(a) inputting the optical signal, the optical signal comprising a plurality of optical channels;

(b) separating one or more of the plurality of optical channels from the optical signal using a plurality of separators, wherein the separators are at least partly arranged in a multi-stage parallel cascade configuration, wherein at least one separator comprises;

at least one lens optically coupled to the inputted optical signal,

at least one lens optically coupled to the outputted plurality of optical channels,

a polarization beam splitter optically coupled to the lenses, and

at least two reflection interferometers optically coupled to the polarization beam splitter, wherein the interferometers introduce a phase difference between at least two of the plurality of optical channels; and

(c) outputting the separated plurality of channels along a plurality of optical paths.

31. A system for separating an optical signal into optical channels, the system comprising:

means for inputting the optical signal, the optical signal comprising a plurality of optical channels;

means for separating one or more of the plurality of optical channels from the optical signal, wherein the separating means is at least partly arranged in a multi-stage parallel cascade configuration, wherein the separating means comprises;

a first glass block coupled to a second glass block, wherein the first glass block is optically coupled to the inputting means,

at least one reflective coating residing between the first and second glass blocks, and

a split beam interferometer optically coupled to the first and second glass blocks, wherein the interferometer introduces a phase difference between at least two of the plurality of optical channels; and

means for outputting the separated plurality of channels along a plurality of optical paths.

32. A system for separating an optical signal into optical channels, the system comprising:

means for inputting the optical signal, the optical signal comprising a plurality of optical channels;

means for separating one or more of the plurality of optical channels from the optical signal, wherein the separating means is at least partly arranged in a multi-stage parallel cascade configuration, wherein the separating means comprises;

at least one lens optically coupled to the inputting means,

at least one lens optically coupled to the outputting means,

a polarization beam splitter optically coupled to the lenses, and

at least two reflection interferometers optically coupled to the polarization beam splitter, wherein the interferometers introduce a phase difference between at least two of the plurality of optical channels; and

means for outputting the separated plurality of channels along a plurality of optical paths.