Reconfigurable optical add/drop multiplexer

• US 20070053633A1
• Filed: 08/16/2005
• Published: 03/08/2007
• Est. Priority Date: 08/16/2005
• Status: Active Grant

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Doerr, Christopher, Leonardus Jennen, Jean
• Granted Patent: US 7,343,066 B2
• Time in Patent Office: Days
• US Class Current: 385/27
• CPC Class Codes: G02B 6/12007 forming wavelength selective elements, e.g. multiplexer, demultiplexer
• CPC Class Codes: G02B 6/12021 Comprising cascaded AWG devices; AWG multipass configuration; Plural AWG devices integrated on a single chip
• CPC Class Codes: G02B 6/2713 cascade of polarisation selective or adjusting operations
• CPC Class Codes: G02B 6/2746 comprising non-reciprocal devices, e.g. isolators, FRM, circulators, quasi-isolators magneto-optic non-reciprocal devices G02F1/093
• CPC Class Codes: G02B 6/2766 Manipulating the plane of polarisation from one input polarisation to another output polarisation, e.g. polarisation rotators, linear to circular polarisation converters
• CPC Class Codes: G02B 6/2773 Polarisation splitting or combining
• CPC Class Codes: G02B 6/29383 Adding and dropping
• CPC Class Codes: G02B 6/29395 configurable, e.g. tunable or reconfigurable switching G02B6/35

Abstract

A reconfigurable optical add/drop multiplexer (ROADM) includes a first optical dynamic gain equalization filter (DGEF) having a first input for receiving an initial wavelength division multiplexed (WDM) signal, a first output for sending a phase shifted WDM signal, and a second output connected to a demultiplexer for demultiplexing a WDM drop signal thereby producing a plurality of drop channels. A second DGEF having a first input for receiving the phase shifted WDM signal, a second input connected to a multiplexer, for multiplexing a plurality of add channels to produce thereby a wavelength division multiplexed (WDM) add signal, and an output for sending a second adjusted WDM signal. The ROADM allows for the channels from the initial WDM signal to be dropped, added and equalized.

Claims

1. An optical add/drop multiplexer (OADM), comprising:

a first coupler, for splitting a wavelength division multiplexed (WDM) add signal into a first component WDM add signal and a second component WDM add signal;

a gain equalizing filter, for processing a WDM input signal and the first component WDM add signal to provide thereby a first component WDM output signal and second component WDM output signal; and

a second coupler, for combining the second component WDM output signal and the second component WDM add signal to produce a WDM drop signal.

2. The OADM of claim 1, further comprising:

a multiplexer, for multiplexing a plurality of add channels to provide thereby the WDM add signal; and

a demultiplexer, for demultiplexing the WDM drop signal to provide thereby a plurality of drop channels;

3. The OADM of claim 1 wherein the gain equalizing filter having a second input port and a second output port.

4. The OADM of claim 1 wherein the multiplexer and demultiplexer are Wavelength Grating Routers (WGR).

5. The OADM of claim 1 wherein the first and second couplers are Y-branch couplers.

6. The OADM of claim 1 wherein the processed WDM signal is phase shifted.

7. The OADM of claim 2 wherein said multiplexer and demultiplexer are connected to an optical circulator and said processed WDM signal is polarization rotated.

8. The OADM of claim 1 wherein the gain equalizing filter is a DGEF.

9. The OADM of claim 1, further comprises an attenuator for attenuating the second component WDM add signal.

10. The OADM of claim 1, further comprises a mirror placed along the axis of symmetry.

11. An optical add/drop multiplexer (OADM) comprising:

a first gain equalizing filter, for processing a wavelength division multiplexed (WDM) input signal to provide thereby a first component WDM drop signal and a second component WDM drop signal; and

a second gain equalizing filter, for processing the first component WDM drop signal and a WDM add signal to provide thereby a WDM output signal.

12. The OADM of claim 11 further comprises:

a demultiplexer, for demultiplexing the second component WDM drop signal to provide thereby a plurality of drop channels; and

a multiplexer, for multiplexing a plurality of add channels to provide thereby the WDM add signal.

13. The OADM of claim 12, wherein the multiplexer and demultiplexer are Wavelength Grating Routers (WGR).

14. The OADM of claim 11, wherein the processed WDM signal is phase shifted.

15. The OADM of claim 11, wherein said multiplexer and demultiplexer are connected to an optical circulator and said processed WDM signal is polarization rotated.

16. The OADM of claim 11 wherein the first and second gain equalizing filters are DGEF'"'"'s.

17. The OADM of claim 11, wherein at least one of the gain equalizing filter includes a non-zero offset phase shifter.

18. An apparatus comprising:

means for splitting a wavelength division multiplexed (WDM) add signal into a first component WDM add signal and a second component WDM add signal;

means for processing a WDM input signal and the first component WDM add signal to provide thereby a first component WDM output signal and second component WDM output signal; and

means for combining the second component WDM output signal and the second component WDM add signal to produce a WDM drop signal.