Photonic cross-connect switch

• US 5,181,134 A
• Filed: 03/15/1991
• Issued: 01/19/1993
• Est. Priority Date: 03/15/1991
• Status: Expired due to Fees

• Current Assignee: American Telephone & Telegraph Company (AT&T, Inc.)
• Original Assignee: AT&T, Inc.
• Inventors: Fatehi, Mohammad T., Srinivasan, Nattu V.
• Primary Examiner(s): Coles, Sr., Edward L.
• Assistant Examiner(s): NEGASH, KINFE MICHAEL
• Application Number:
  US07/669,840
• Time in Patent Office: 676 Days
• Field of Search: 359/128, 359/134, 359/139, 359/160, 359/117-118, 359/120-121, 359/108, 359/341, 372/6, 385/16, 385/17
• US Class Current: 398/56
• CPC Class Codes: G02B 6/28 having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals

Abstract

This invention relates to an optical cross-connect switch which is substantially loss-less and is transparent to signal bit rate, format and modulation scheme. The optical cross-connect switch can be comprised of at least two stages of chips coupled in tandem via optical fibers. Each chip can be of lithium niobate having a plurality of digital switch elements or directional couplers which, by means of an electric field, can selectively switch optical energy from one waveguide to another. The chips are coupled together via optical fiber amplifiers and the optical fiber amplifiers are pumped by optical pumps, e.g., 1.48 μm CW, laser pumps, coupled to appropriate nodes within either one or both of the chips. In operation, the pump energy is switched through the chips along with the optical data signals to pump only those optical fiber amplifiers which are in the optical data signal path.

Claims

1. An optical cross-connect switch comprising

a first group of crystals of dielectric material

a first group of waveguides supported by said first group of crystals of dielectric material for carrying optical signals from an input port to a selected output port,

a first group of switching means coupled to said waveguides for selectively switching optical signals from said input ports along selective waveguides to said output ports,

a second group of crystals of dielectric material,

a second group of waveguides supported by said second group of crystals of dielectric material for carrying optical signals from an input port to a selected output port,

a second group of switching means coupled to said waveguides for selectively switching optical signals from said input ports along selective waveguides to said output ports,

optical fibers interposed between the output ports of said first group of waveguides and the input ports of said second group of waveguides to form an optical fiber interconnect web,

said optical fibers comprise optical fiber amplifiers, and

pump means coupled to pump said optical fiber amplifiers from a remote location.

2. The optical cross-connect switch of claim 1 wherein

said pump means is coupled to the output ports of said second group of waveguides supported by said second group of crystals.

3. The optical cross-connect switch of claim 2 wherein

the number of input ports of said first group of waveguides supported by said first group of crystals is equal to the number of output ports of said second group of waveguides supported by said second group of crystals and less than the number of optical fibers of the optical fiber interconnect web.

4. The optical cross-connect switch of claim 1 wherein

said pump means is coupled to the input ports of said first group of waveguides supported by said first group of crystals.

5. The optical cross-connect switch of claim 4 wherein

the number of input ports of said first group of waveguides supported by said first group of crystals is equal to the number of output ports of said second group of waveguides supported by said second group of crystals and less than the number of optical fibers of the optical fiber interconnect web.

6. The optical cross-connect switch of claim 5 wherein said pump means comprises a laser pump coupled to said input ports.

7. The optical cross-connect switch of claim 6 wherein said pump means comprises a separate laser pump coupled to each of said input ports.

8. The optical cross-connect switch of claim 6 wherein said first group of waveguides are coupled to at least four input ports and said second group of waveguides are coupled to at least four output ports.