Reconfigurable wavelength division multiplex add/drop device using micromirrors

• US 6,204,946 B1
• Filed: 11/12/1997
• Issued: 03/20/2001
• Est. Priority Date: 08/21/1997
• Status: Expired due to Term

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Ford, Joseph E., Walker, James A., Aksyuk, Vladimir A., Bishop, David J.
• Primary Examiner(s): NEGASH, KINFE MICHAEL
• Application Number:
  US08/968,935
• Time in Patent Office: 1,224 Days
• Field of Search: 359/124, 359/129-131, 359/128, 385/24
• US Class Current: 398/9
• CPC Class Codes: G02B 6/2931 Diffractive element operating in reflection
• CPC Class Codes: G02B 6/29313 characterised by means for controlling the position or direction of light incident to or leaving the diffractive element, e.g. for varying the wavelength response switching G02B6/35
• CPC Class Codes: G02B 6/29383 Adding and dropping
• CPC Class Codes: G02B 6/3512 the optical element being reflective, e.g. mirror
• CPC Class Codes: G02B 6/356 in an optical cross-connect device, e.g. routing and switching aspects of interconnecting different paths propagating different wavelengths to (re)configure the various input and output links switching polarized beams G02B6/3594; power equalizers G02B6/356 and G02B6/3594; path selecting means H04Q11/0001
• CPC Class Codes: H04J 14/0206 Express channels arrangements
• CPC Class Codes: H04J 14/021 Reconfigurable arrangements, e.g. reconfigurable optical add/drop multiplexers [ROADM] or tunable optical add/drop multiplexers [TOADM]
• CPC Class Codes: H04J 14/0213 Groups of channels or wave bands arrangements
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 2011/0015 using splitting combining
• CPC Class Codes: H04Q 2011/0016 using wavelength multiplexing or demultiplexing
• CPC Class Codes: H04Q 2011/0026 using free space propagation (e.g. lenses, mirrors)
• CPC Class Codes: H04Q 2011/0032 using static wavelength routers (e.g. arrayed waveguide grating router [AWGR] )
• CPC Class Codes: H04Q 2011/0035 using miscellaneous components, e.g. circulator, polarisation, acousto/thermo optical
• CPC Class Codes: H04Q 2011/0041 Optical control

Abstract

A WDM add/drop device for use in an optic communications system for adding and dropping optical wavelengths from a multiple-wavelength optical system. The device includes a set of lenses, a planar grating wavelength multiplexer and a micromirror array switchable for individual wavelengths of the multiple-wavelength signal between a transmit mode and a reflect mode. The grating angularly demultiplexes a multiple-wavelength optical signal in a first direction and the individual wavelengths are processed by the micromirror array and directed to the grating in a second direction. The micromirror array will either reflect select wavelengths to a first port or transmit select wavelengths to a second port. In a preferred embodiment, ports on a first multiport circulator input the multiple-wavelength optical signal to the WDM add/drop device and output the multiple-wavelength optical signal from the WDM add/drop device. A second multiport circulator provides to-be-added wavelengths to the WDM add/drop device and removes to-be-dropped wavelengths from the WDM add/drop device.

Claims

1. A WDM transmit/reflect unit for selectively transmitting a select wavelength of a multiple-wavelength optical signal from at least one first optic fiber to at least one second optic fiber and reflecting the select wavelength from the at least one first optic fiber back to the at least one first optic fiber, said unit comprising:

a first port for receiving the multiple-wavelength optical signal from the at least one first optic fiber;

a first lens for collimating the received multiple-wavelength optical signal;

means for angularly displacing from each other individual ones of the multiple wavelengths in the collimated multiple-wavelength optical signal when the multiple-wavelength optical signal is travelling in a first direction, and for angularly combining the individual wavelengths of the multiple-wavelength optical signal when the multiple-wavelength optical signal is travelling in a second direction;

a second lens for focusing the angularly displaced wavelengths when the multiple-wavelength signal is travelling in the first direction and for collimating the multiple-wavelength signal when the multiple-wavelength signal is travelling in the second direction;

a micromirror array for receiving the multiple-wavelength signal from the second lens and selectively switchable between a transmission mode for transmitting the select wavelength to the at least one second optic fiber and a reflection mode for reflecting the select wavelength to the at least one first optic fiber;

a second port connected to the second fiber for receiving the deflected angularly combined optical signal from said angularly displacing means when the array is in the transmit mode; and

a third lens positioned between said grating and said second port for focusing the angularly combined multiple-wavelength signal onto said second port for receipt by the second fiber.

2. The WDM transmit/reflect unit of claim 1, wherein when said micromirror array is in said transmission mode, and when a second multiple-wavelength signal is present at said second port, the second multiple-wavelength signal is transmitted to said first port.

3. The WDM transmit/reflect unit of claim 1, wherein said micromirror array comprises a plurality of mirror plates, with each plate positioned for receiving one of the individual wavelengths of said multiple-wavelength signal.

4. The WDM transmit/reflect unit of claim 3, wherein each mirror plate is responsive to an electrical signal for selectively activating each plate between the transmission mode and the reflection mode.

5. The WDM transmit/reflect unit of claim 3, wherein each mirror plate is responsive to an electrical signal for selectively reorienting each plate between the transmission mode and the reflection mode.

6. The WDM transmit/reflect unit of claim 3, wherein said micromirror array has a vertical axis, wherein each mirror plate has a vertical axis, and each said mirror plates is arranged so that its vertical axis is angularly offset from the vertical axis of said mirror array.

7. The WDM transmit/reflect unit of claim 6, wherein each said mirror plate of the micromirror array is selectively rotatable about its axis to transmit or reflect select wavelengths of the multiple-wavelength optical signal.

8. The WDM transmit/reflect unit of claim 1, wherein said angularly displacing means comprises a grating.

9. The WDM transmit/reflect unit of claim 3, wherein said plural mirror plates are arranged in a column.

10. The WDM transmit/reflect unit of claim 3, wherein the at least one first optic fiber comprises a first plurality of optic fibers, each providing a multiple-wavelength optical signal to said first port, wherein the at least one second optic fiber comprises a second plurality of optic fibers, equal in number to the plurality of first optic fibers and each of the second optic fibers receiving an angularly combined deflected multiple-wavelength signal from said second port, and wherein said plural mirror plates are arranged to form a plurality of columns of said mirror plates equal in number of columns to the plurality of optic fibers in the first plurality of optic fibers, and wherein each said column of mirror plates comprises a plural number of mirror plates at least equal to the multiple wavelengths in each multiple wavelength optical signal.

11. The WDM transmit/reflect unit of claim 1, further comprising a deflecting element positioned between said angularly displacing means and said third lens for deflecting the angularly combined multiple-wavelength signal to the at least one second optic fiber when the array is in the transmitting mode.

12. The WDM transmit/reflect unit of claim 1, further comprising a polarization dependent optical component positioned between said angularly displacing means and said second lens.

13. The WDM transmit/reflect unit of claim 12, wherein said polarization dependent optical component comprises a quarter-wave plate.

14. A WDM add/drop device for adding wavelengths to and dropping wavelengths from a multiple-wavelength optical signal in an optical communication system, comprising:

an input port for receiving a WDM multiple-wavelength input optical signal from at least one first optic fiber;

an output port for outputting a WDM multiple-wavelength output optical signal to at least one second optic fiber;

a WDM add port for receiving as an input an add wavelength to be added to the multiple-wavelength optical signal;

a WDM transmit/reflect unit having a first port and a second port for transmitting one of the multiple wavelengths of the multiple-wavelength signal from the first port to the second port in a first direction, for transmitting the added wavelength from the second port to the first port in a second direction, and for reflecting one of the multiple wavelengths of the multiple-wavelength signal from the first port back to the first port;

a first multiport circulator disposed between said WDM input port, said WDM output port and said first port of said WDM transmit/reflect unit, said circulator being operable for receiving the WDM multiple-wavelength input signal from said input port and providing the WDM input signal to said first port of said WDM transmit/reflect unit and for receiving the WDM multiple-wavelength signal reflected by said WDM transmit/reflect unit and the added wavelength transmitted by said WDM transmit/reflect unit and providing the received reflected WDM multiple-wavelength signal and added wavelength to said output port;

a WDM drop port for outputting from the WDM input signal, one of the multiple wavelengths dropped from the WDM multiple-wavelength optical signal transmitted by said WDM transmit/reflect unit; and

a second circulator disposed between said WDM add port, said WDM drop port and said second port of said WDM transmit/reflect unit for forwarding one of the multiple transmitted wavelengths from the WDM transmit/reflect unit to said WDM drop port and for forwarding the WDM added wavelength from said WDM add port to said second port of said WDM transmit/reflect unit.

15. The WDM add/drop device of claim 14, wherein said WDM transmit/reflect unit further comprises a micromirror array having a plurality of mirror plates, with each plate positioned for receiving one of the wavelengths of said multiple-wavelength input optical signal, and means for optical wavelength demultiplexing of the multiple wavelength signal onto said plurality of mirror plates.

16. The WDM add/drop device of claim 15, wherein each mirror plate in said micromirror array is responsive to an electrical signal for selectively activating each plate between transmission and reflection modes of the WDM transmit/reflect unit.

17. The WDM add/drop device of claim 15, wherein each mirror plate in said micromirror array is responsive to an electrical signal for selectively reorienting each plate between a transmission mode and a reflection mode.

18. The WDM add/drop device of claim 15, wherein said micromirror array has a vertical axis, wherein each mirror plate has a vertical axis, and wherein each said mirror plate is arranged so that its vertical axis is angularly offset from the vertical axis of said mirror array.

19. The WDM add/drop device of claim 15, wherein each said mirror plates of the micromirror array is selectively rotatable about its axis to transmit or reflect select wavelengths of the multiple-wavelength optical signal.

20. The WDM add/drop device of claim 15, wherein said plural mirror plates are arranged in a column.

21. The WDM add/drop device of claim 15, wherein said first port comprises a first port on a multiple port circulator and said second port comprises a second port on said multiple port circulator, wherein the at least one first optic fiber comprises a first plurality of optic fibers, each providing a multiple-wavelength optical signal to said first port, wherein the at least one second optic fiber comprises a second plurality of optic fibers, equal in number to the plurality of first optic fibers and each of the second optic fibers receiving an output multiple-wavelength optical signal from said second port, and wherein said plural mirror plates are arranged to form a plurality of columns of said mirror plates equal in number of columns to the plurality of optic fibers in the first plurality of optic fibers, and wherein each said column of mirror plates comprises a plural number of mirror plates at least equal to the multiple wavelengths in each multiple-wavelength optical signal.

22. A WDM transmit/reflect unit for selectively transmitting a select wavelength of a multiple-wavelength optical signal from a first optic fiber to a second optic fiber and reflecting the select wavelength from the first optic fiber back to the first optic fiber, said unit comprising:

a first port for receiving the multiple-wavelength optical signal from the first fiber;

means for angularly displacing from each other individual ones of the multiple wavelengths in the multiple-wavelength optical signal when the multiple-wavelength optical signal is travelling in a first direction, and for angularly combining the individual wavelengths of the multiple-wavelength optical signal when the multiple-wavelength optical signal is travelling in a second direction;

first means for imaging the angularly displaced multiple-wavelength optical signal to form an image;

a micromirror array for receiving the image from said first imaging means, said micromirror array being selectively switchable between a transmission mode for transmitting the select wavelength to the second fiber and a reflection mode for reflecting the select wavelength to the first fiber;

said first imaging means operatively imaging the reflected select wavelength at said first port for receipt by the first optic fiber when said micromirror array is in said reflection mode;

second imaging means for imaging the transmitted select wavelength when said micromirror array is in said transmission mode; and

a second port connected to the second fiber for receiving the image of the transmitted select wavelength from said second imaging means.

23. The WDM transmit/reflect device of claim 22, wherein said means for angularly displacing individual ones of the multiple wavelengths comprises an optical grating.

24. The WDM transmit/reflect device of claim 22, wherein said first imaging means comprises a lens disposed between said angularly displacing means and said micromirror array.

25. The WDM transmit/reflect device of claim 24, wherein said first imaging means further comprises a focusing lens disposed between said angularly displacing means and said first port for focusing the image of the reflected wavelength on said first port.

26. The WDM transmit/reflect device of claim 24, wherein said second imaging means comprises a focusing lens disposed between said angularly displacing means and said second port for focusing the image of the transmitted wavelength on said second port.