US6271944B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Laser wavelength control in an optical communication system
Assignee: Philips North America LLC
•
Filing: 1999-06-30
•
Granted: 2001-08-07
•
Expires: 2019-06-30
Abstract
Abstract A method and apparatus for controlling and stabilizing laser wavelengths in a dense wavelength division multiplexer (DWDM) transmission system. The lasers in the transmission system are each modulated in a known manner by a data signal. In addition, the lasers are each modulated by a plurality of test signals each having a predetermined frequency. At the optical receiver, a frequency analyzer examiners the frequency test signals for distortions and/or changes in amplitude. Any distortions and/or changes in amplitude of the frequency test signals indicate a change in the wavelength of a corresponding laser. A control signal may be returned to the laser controller of each laser to regulate the laser wavelength. A fault signal may be generated indicating that the wavelength of a laser has changed, drifted, etc., more an acceptable amount.
Inventors
- 👤 Marcel F. C. Schemmann
- 👤 Venkatesh G. Mutalik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 23:42
CPC Classifications
H; H04; H04J; H04J14/00; H04J14/02; H04J14/0298; H04B; H04B10/00; H04B10/07; H04B10/075; H04B10/077; H04B10/0771; H04B10/0775; H04B10/50; H04B10/501; H04B10/506; H04B10/572; H04B2210/00; H04B2210/07; H04B2210/071; H04B2210/078
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
105 words
An optical communication system comprising: a plurality of optical sources each having a distinct wavelength; a system for modulating each of the optical sources with a data signal and a first and second frequency test signal, thereby producing a plurality of optical signals; a wavelength division multiplexer (WDM) for receiving the plurality of optical signals and for outputting a multiplexed optical signal; a wavelength division demultiplexer (WDD) for receiving and the multiplexed optical signal into the plurality of optical signals; and a system for analyzing the frequency test signals in each optical signal to indicate a change in the wavelength of the corresponding optical source.
Claim 2
Dependent Claim
105 words
An optical communication system comprising: a plurality of optical sources each having a distinct wavelength; a system for modulating each of the optical sources with a data signal and a first and second frequency test signal, thereby producing a plurality of optical signals; a wavelength division multiplexer (WDM) for receiving the plurality of optical signals and for outputting a multiplexed optical signal; a wavelength division demultiplexer (WDD) for receiving and the multiplexed optical signal into the plurality of optical signals; and a system for analyzing the frequency test signals in each optical signal to indicate a change in the wavelength of the corresponding optical source.
Claim 3
Dependent Claim
26 words
The optical communication system of claim 1 , wherein the analyzing system outputs a plurality of control signals each corresponding to one of the optical signals.
Claim 4
Dependent Claim
31 words
The optical communication system of claim 1 , further comprising: a system for regulating each of the optical sources based on said plurality of control signals output by the analyzing system.
Claim 5
Dependent Claim
23 words
The optical communication system of claim 3 , further including: a system for transmitting the plurality of control signals to the regulating system.
Claim 6
Dependent Claim
35 words
The optical communication system of claim 1 , further comprising: a system for identifying a fault status in each of the optical sources based on said plurality of control signals output by the analyzing system.
Claim 7
Dependent Claim
17 words
The optical communication system of claim 1 , wherein each frequency test signal comprises a predetermined frequency.
Claim 8
Dependent Claim
19 words
The optical communication system of claim 1 , wherein the analyzing system examines the frequency test signals for distortions.
Claim 9
Dependent Claim
59 words
The optical communication system of claim 7 , wherein the frequency test signals include a first frequency test signal f 1 and a second frequency test signal f 2 , and wherein a distortion of the frequency test signals f 1 and f 2 is determined according to Δ(f 1 +f 2 ) or Δ(f 1 −f 2 ).
Claim 10
Dependent Claim
21 words
The optical communication system of claim 1 , wherein the analyzing system examines the frequency test signals for changes in amplitude.
Claim 11
Dependent Claim
88 words
An optical communication method comprising the steps of: providing a plurality of optical sources each having a distinct wavelength; modulating each of the optical sources with a data signal and a first and second frequency test signal to produce a plurality of optical signals; converting the plurality of optical signals into a multiplexed optical signal; separating the multiplexed optical signal into the plurality of optical signals; and analyzing the frequency test signals in each optical signal to indicate a change in the wavelength of the corresponding optical source.
Claim 12
Dependent Claim
88 words
An optical communication method comprising the steps of: providing a plurality of optical sources each having a distinct wavelength; modulating each of the optical sources with a data signal and a first and second frequency test signal to produce a plurality of optical signals; converting the plurality of optical signals into a multiplexed optical signal; separating the multiplexed optical signal into the plurality of optical signals; and analyzing the frequency test signals in each optical signal to indicate a change in the wavelength of the corresponding optical source.
Claim 13
Dependent Claim
25 words
The method of claim 10 , further including the step of: generating a plurality of control signals each corresponding to one of the optical signals.
Claim 14
Dependent Claim
24 words
The method of claim 11 , further comprising the step of: regulating each of the optical sources based on the corresponding generated control signal.
Claim 15
Dependent Claim
28 words
The method of claim 11 , further comprising the step of: identifying a fault status in each of the optical sources based on the corresponding generated control signal.
Claim 16
Dependent Claim
15 words
The method of claim 10 , wherein each frequency test signal comprises a predetermined frequency.
Claim 17
Dependent Claim
22 words
The method of claim 10 , wherein the analyzing step further comprises the step of: examining the frequency test signals for distortions.
Claim 18
Dependent Claim
57 words
The method of claim 15 , wherein the frequency test signals include a first frequency test signal f 1 and a second frequency test signal f 2 , and wherein a distortion of the frequency test signals f 1 and f 2 is determined according to Δ(f 1 +f 2 ) or Δ(f 1 −f 2 ).
Claim 19
Dependent Claim
24 words
The method of claim 10 , wherein the analyzing step further comprises the step of: examining the frequency test signals for changes in amplitude.
Claim 20
Dependent Claim
107 words
A wavelength stabilization system comprising: a plurality of optical sources each having a distinct wavelength; a system for modulating each of the optical sources with a data signal and a first and second frequency test signal to produce a plurality of optical signals; a system for analyzing the frequency test signals in each optical signal to indicate a change in the wavelength of the corresponding optical source, and for generating a plurality of control signals each corresponding to one of the optical signals; and a controller for regulating the wavelength of each of the optical sources based on the corresponding control signal generated by the analyzing system.
Claim 21
Dependent Claim
107 words
A wavelength stabilization system comprising: a plurality of optical sources each having a distinct wavelength; a system for modulating each of the optical sources with a data signal and a first and second frequency test signal to produce a plurality of optical signals; a system for analyzing the frequency test signals in each optical signal to indicate a change in the wavelength of the corresponding optical source, and for generating a plurality of control signals each corresponding to one of the optical signals; and a controller for regulating the wavelength of each of the optical sources based on the corresponding control signal generated by the analyzing system.
Claim 22
Dependent Claim
20 words
The wavelength stabilization system according to claim 18 , wherein the analyzing system examines the frequency test signals for distortions.
Claim 23
Dependent Claim
60 words
The wavelength stabilization system according to claim 19 , wherein the frequency test signals include a first frequency test signal f 1 and a second frequency test signal f 2 , and wherein a distortion of the frequency test signals f 1 and f 2 is determined according to Δ(f 1 +f 2 ) or Δ(f 1 −f 2 ).
Claim 24
Dependent Claim
22 words
The wavelength stabilization system according to claim 18 , wherein the analyzing system examines the frequency test signals for changes in amplitude.
Claim 25
Independent Claim
95 words
A method for wavelength stabilization comprising the steps of: providing a plurality of optical sources each having a distinct wavelength; modulating each of the optical sources with a data signal and a first and second frequency test signal to produce a plurality of optical signals; analyzing the frequency test signals in each optical signal to indicate a change in the wavelength of the corresponding optical source, and generating a control signal in response thereto; and regulating the wavelength of each of the optical sources based on the corresponding control signal generated by the analyzing system.
Claim 26
Independent Claim
95 words
A method for wavelength stabilization comprising the steps of: providing a plurality of optical sources each having a distinct wavelength; modulating each of the optical sources with a data signal and a first and second frequency test signal to produce a plurality of optical signals; analyzing the frequency test signals in each optical signal to indicate a change in the wavelength of the corresponding optical source, and generating a control signal in response thereto; and regulating the wavelength of each of the optical sources based on the corresponding control signal generated by the analyzing system.
Claim 27
Dependent Claim
19 words
The method according to claim 22 , further including the step of: examining the frequency test signals for distortions.
Claim 28
Dependent Claim
65 words
The method according to claim 23 , wherein the frequency test signals include a first frequency test signal f 1 and a second frequency test signal f 2 , and wherein the examining step further includes the step of: determining a distortion of the frequency test signals f 1 and f 2 according to Δ(f 1 +f 2 ) or Δ(f 1 −f 2 ).
Claim 29
Dependent Claim
25 words
The method according to claim 22 , wherein the analyzing step further includes the step of: examining the frequency test signals for changes in amplitude.
References Cited (Backward Citations)
JPH0346839A
Cited
US5225922A
Cited
US5548434A
Cited
US5654816A
Cited
US5920414A
Cited
US5790289A
Cited
US5801860A
Cited
EP0798882A2
Cited
EP0862291A2
Cited
DE19734957C1
Cited
US5995256A
Cited
WO1999033200A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-08-06 | 2005-02-05 | 2005-08-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-08-06 | 2009-02-05 | 2009-08-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-08-06 | 2013-02-05 | 2013-08-07 | $7700.00 | Window Closed / Lapsed |