Method and apparatus for monitoring and control of laser emission wavelength

United States Patent [w]

Munks et al.

[54] METHOD AND APPARATUS FOR

MONITORING AND CONTROL OF LASER
EMISSION WAVELENGTH

[75] Inventors: Timothy C. Munks, Crystal Lake, 111.;

Paul E. Dunn, Westfield, Mass.; David
J. Allie, Storrs, Conn.

[73] Assignee: JDS Uniphase Corporation, San Jose, Calif.

[21] Appl. No.: 09/025,987 [22] Filed: Feb. 19, 1998

[51] Int. CI.7 HOIS 3/00

[52] U.S. CI 372/38; 372/9; 372/23;

372/25; 372/29; 372/32; 372/33

[58] Field of Search 372/9, 23, 24,

372/29, 32, 33, 38, 34, 25

[56] References Cited

U.S. PATENT DOCUMENTS

4,737,798 4/1988 Lonis et al 372/29 X

4,815,081 3/1989 Mahlein et al 372/32

4,821,273 4/1989 Hori 372/34 X

4,913,525 4/1990 Asakura et al 350/162.12

4,955,029 9/1990 Lecoy et al 372/38 X

5,042,042 8/1991 Hori et al 372/32 X

5,068,864 11/1991 Javan 372/32

5,208,819 5/1993 Huber 372/34

5,287,367 2/1994 Yanagawa 372/31

5,299,212 3/1994 Koch et al 372/32

5,313.480 5/1994 Fidric et al 372/32

5,323,409 6/1994 Laskoskie et al 372/32

5,428,700 6/1995 Hall 372/32

5,544,183 8/1996 Takeda 372/38

5,577,059 11/1996 Lee et al 372/22

5,691,989 11/1997 Rakuljic et al 372/20

5,706,301 1/1998 Lagerstrom 372/32

5,780,843 7/1998 Cliche et al 250/226

5,781,572 7/1998 Tahaia et al 372/34

5,798,859 8/1998 Colbourne et al 359/247

5,825,792 10/1998 Villeneuve et al 372/32

5,867,513 2/1999 Sato 372/32

5,915,052 6/1999 Ball 385/24

"Properties of Loss-Coupled Distributed Feedback Laser Arrays for Wavelength Division Multiplexing Systems", by Stefan Hansmann, et al., Journal of Lightwave Technology vol. 15, No. 7 (Jul. 1997).

(List continued on next page.)

Primary Examiner—Brian Healy

Attorney, Agent, or Firm—McCormick, Paulding & Huber LLP

[57] ABSTRACT

An apparatus for monitoring and controlling the wavelength of laser radiation includes at a least one optical filter for receiving laser radiation and for transmitting and reflecting first and second filtered beams, respectively. The beams are filtered according to respective first and second spectral filter functions that cross at least one crossing wavelength. A beam comparing element compares the intensities of the first and second filtered beams and produces an error signal responsive to the deviation of the wavelength of the laser radiation from a set point wavelength. The beam comparing element can include first and second optical detectors and an error circuit for producing the error signal by taking a ratio or the difference of the signals detected by the detectors. Varying the angle of incidence of the laser radiation upon at least one optical filter varies the spectral filter function of that for selecting or varying the operating wavelength of the laser. A laser wavelength controller can receive the error signal for stabilizing or tuning the wavelength of the laser radiation. Several addition embodiments of the invention are disclosed.

40 Claims, 17 Drawing Sheets

OTHER PUBLICATIONS

"Single-Angled-Facet Laser Diode for Widely Tunable External Cavity Semiconductor Lasers with High Spectral Purity", by P.J.S. Heim, et al., Electronics Letters, vol. 33, No. 16 (Jul. 31, 1997).

"Monolithic Mode-Locked Semiconductor Laser for Continuously Tunable Millimeter-Wave Transmission", by Dennis T.K. Tong, et al., SPIE, vol. 3038. "2.5 Gbit/s Directly-Modulated Fibre Grating Laser for WDM Networks", by F.N. Timofeev, et al., Electronics Letters, vol. 33, No. 16 (Jul. 31 1997).

"2.5 Gbit/s Directly-Modulated Fibre Grating Laser for Optical Networks", by F.N. Timofeev, et al., The Institute of Electrical Engineers, 1997.

"Visible Laser Sources Based on Frequency Doubling in Nonlinear Waveguides", by Jonas Webjorn, et al., IEEE, 1997.

"Experimental Demostration of an All-Optical Routing Node for Multihop Wavelength Routing Networks", by M. Shell, et al, IEEE, 1996.

"Continuously Chirped DFB Gratings by Specially Bent Waveguides for Tunable Lasers", by Hartmut Hillmer, et al., Journal of Lightwave Technology, vol. 13, No. 9 (Sep. 1995).

"Sprectral Dynamics of Widely Tunable Four-Section Sampled Grating DBR Lasers", by Gardiner, et al., Conference Proceedings -Lasers and Electro-Optics Society Annual Meeting Proceedings of the 1996 Conference on Lasers and Electro-Optics, ELEO'96 (Jun. 2-7, 1996). "Optical Frequency Switching with SSG-DBR Structured Devices", by Hiroshi Yasaka, et al., NTT Opto-Electronics Laboratories(1995).

"Wavelength Tuning in Three Section Sampled Grating DBR Lasers", C.K. Gardiner, et al., Electronics Letters, vol. 31, No. 15 (Jul. 20, 1995).

"A2.5-Gbit/s Return-to-Zero Integrated DBR Laser/Modu-
lator Transmitter", by G. Raybon, et al., IEEE Photonics
Technology Letters, vol. 6, No. 11 (Nov. 1994).
"Tunable Lasers for Photonic Integrated Circuits", by L.A.
Coldren, et al., CLEOS Summer Topical Meeting Integrated
Optoeelectronics Proceedings of the CLEOS 1994 Summer
Topical MeetingQuX. 6-8, 1994).