Optical communication system with a stabilized "comb" of frequencies

• US 4,989,201 A
• Filed: 12/21/1989
• Issued: 01/29/1991
• Est. Priority Date: 06/09/1987
• Status: Expired due to Term

• Current Assignee: AT&T, Inc.
• Original Assignee: AT&T, Inc.
• Inventors: Glance, Bernard
• Primary Examiner(s): PASCAL, LESLIE C
• Assistant Examiner(s): Van Beek, L.
• Application Number:
  US07/455,898
• Time in Patent Office: 404 Days
• Field of Search: 350/96.15, 350/96.16, 370/1, 370/3, 372/18, 372/20, 372/29, 372/32, 455/606, 455/607, 455/612, 455/617, 455/609, 455/610, 455/611, 455/613, 455/618
• US Class Current: 398/95
• CPC Class Codes: H01S 3/1303 by using a passive reference, e.g. absorption cell H01S3/139 takes precedence
• CPC Class Codes: H04B 10/50 Transmitters
• CPC Class Codes: H04B 10/506 Multiwavelength transmitters
• CPC Class Codes: H04B 10/572 Wavelength control

Abstract

An optical communication system in which a group, or "comb", of intelligence-bearing signals are frequency-division-multiplexed and stabilized using a corresponding "comb" of resonances associated with a Fabry-Perot cavity.

Claims

1. An optical communication system to process at least three intelligence-bearing, frequency-multiplexed, modulated optical signals comprising:

means for frequency multiplexing the at least three signals,

at least one Fabry-Perot cavity with resonances at the frequencies of the at least three signals and with which cavity the signals interact,

means for applying a dithering frequency to at least one of the at least three signals to yield at least one dithered signal,

a feedback loop associated with the at least one dithered signal to generate an error signal proportional to drifting of at least one detected parameter of the at least one dithered signal, and

means for adjusting a device in response to the error signal.

2. The communications system of claim 1 comprising at least two Fabry-Perot cavities, and in which system one of the signals is a reference signal, and the said feedback loop is connected to detect drift in the detected reference signal.

3. The communications system of claim 2 in which there is a feedback loop associated with each of the Fabry-Perot cavities to detect drift in the detected reference signal at each of the Fabry-Perot cavities.

4. The communications system of claim 3 in which the signals are transmitted through at least one of the Fabry-Perot cavities.

5. The communications system of claim 3 in which the signals are reflected of at least one of the Fabry-Perot cavities.

6. The communications system of claim 1 in which there exist cavity resonances at the frequencies of each of the signals.