Patent
Series of strongly complex coupled DFB lasers
| العنوان: | Series of strongly complex coupled DFB lasers |
|---|---|
| Patent Number: | 6,104,739 |
| تاريخ النشر: | August 15, 2000 |
| Appl. No: | 08/998,071 |
| Application Filed: | December 24, 1997 |
| مستخلص: | A one dimensional series of complex coupled (gain or loss coupled) DFB semiconductor lasers is disclosed. Each laser comprises a multiple quantum well active region and a complex coupled grating having corrugations along a cavity length direction formed by periodically etching grooves through the active region. The grating has a period comprising a first section and a second section, wherein substantially all quantum wells are etched away from the second section providing no substantial photon generation in the second section. The depth of etching is defined so as to provide a substantial insensitivity of each laser to the external feedback and random facet variations and to ensure no substantial interaction between lasers in the series. The lasers in the series may further comprise means for tuning laser wavelengths around corresponding lasing modes and/or means for switching between the lasing modes. The series of lasers is also capable of simultaneous multi-wavelength generation, with the number of generated wavelengths being equal to a number of lasers in the series excited above threshold levels. |
| Inventors: | Hong, Jin (Nepean, CAX); Kim, Hyung B. (Kanata, CAX); Makino, Toshihiko (Nepean, CAX) |
| Assignees: | Nortel Networks Corporation (Montreal, CAX) |
| Claim: | What is claimed is |
| Claim: | 1. A series of semiconductor lasers having an output facet, comprising |
| Claim: | a plurality of complex coupled distributed feedback semiconductor lasers having laser cavities arranged in a series coaxially along same optical axis, each laser comprising |
| Claim: | (a) substrate; |
| Claim: | (b) an active region formed on the substrate and comprising a multiple quantum well structure; |
| Claim: | (c) an excitation means for pumping the active region; |
| Claim: | (d) a complex coupled grating having corrugations along the optical axis formed by periodic etching grooves through the active region, the grating having a period comprising a first section and a second section, wherein substantially all quantum wells are removed away from the second section so as to provide no substantial photon emission in the second section resulting in gain coupling and index coupling of the laser of such a magnitude that ensures no substantial interaction between lasers in the series, stable generation of light in the presence of other lasers in the series and provides the required stopband of the laser; |
| Claim: | a Bragg wavelength of each laser in the series being outside the stop bands of all other lasers which are closer to the output facet of the series. |
| Claim: | 2. A series of lasers as defined in claim 1, wherein the series has only one output facet. |
| Claim: | 3. A series of lasers as defined in claim 2, wherein each laser is a gain coupled laser comprising a gain coupled grating. |
| Claim: | 4. A series of lasers as defined in claim 2, wherein each laser is a loss coupled laser comprising a loss coupled grating. |
| Claim: | 5. A series of lasers as defined in claim 3, wherein each laser generates at the right Bragg mode around its stop band, and the Bragg modes of lasers differ so as to provide a continuous tuning range for the series as a whole. |
| Claim: | 6. A series of lasers as defined in claim 4, wherein each laser generates at the left Bragg mode around its stop band, and the Bragg modes of lasers differ so as to provide a continuous tuning range for the series as a whole. |
| Claim: | 7. A series of lasers as defined in claim 1, further comprising means for tuning a laser wavelength of each laser around a corresponding lasing mode. |
| Claim: | 8. A series of lasers as defined in claim 1, capable of multi-wavelength generation, wherein the number of generated wavelengths is equal to a number of lasers in the series excited above threshold levels. |
| Claim: | 9. A series of lasers as defined in claim 1, further comprising means for wavelength switching between lasing modes generated by lasers in the series. |
| Claim: | 10. A series of lasers as defined in claim 9, wherein the means for wavelength switching provides switching within a time interval of several nanoseconds. |
| Claim: | 11. A series of lasers as defined in claim 1, wherein a height and a shape of the sections of the grating period define photon emission in the sections. |
| Claim: | 12. A series of lasers as defined in claim 11, wherein the first and second sections have a rectangular or trapezoidal shape. |
| Claim: | 13. A series of lasers as defined in claim 11, wherein the second section is V-shaped. |
| Claim: | 14. A series of lasers as defined in claim 1, wherein the grating is a first order grating. |
| Claim: | 15. A series of lasers as defined in claim 1, wherein the grating is a chirped grating. |
| Claim: | 16. A series of lasers as defined in claim 1, wherein the means for pumping the active region comprises electrical contacts for current injection into the active region. |
| Claim: | 17. A series of lasers as defined in claim 16, wherein a current confining region is formed on the active region. |
| Claim: | 18. A series of lasers as defined in claim 17, wherein the current confining region is a ridge waveguide. |
| Claim: | 19. A series of lasers as defined in claim 17, wherein the current confining region is a buried heterostructure. |
| Claim: | 20. A series of lasers as defined in claim 1, wherein the means for pumping the active region comprises an external optical pumping source. |
| Claim: | 21. A series of lasers as defined in claim 18, wherein the substrate is p-type and the ridge is N-type. |
| Claim: | 22. A series of lasers as defined in claim 18, wherein the substrate is N-type and the ridge is P-type. |
| Claim: | 23. A series of lasers as defined in claim 17, wherein the substrate is InP. |
| Claim: | 24. A series of lasers as defined in claim 23, capable of generating light in the wavelength range of 1.3-1.56 micrometers. |
| Claim: | 25. A series of lasers as defined in claim 17, wherein the substrate is GaAs. |
| Claim: | 26. A series of lasers as defined in claim 25, capable of generating light in the wavelength range of 0.80-0.9 micrometers. |
| Claim: | 27. A series of lasers as defined in claim 1, wherein the lasers in the series are equally spaced from each other. |
| Claim: | 28. A series of lasers as defined in claim 27, wherein the center to center spacing of respective lasers is within a range of several micrometers. |
| Current U.S. Class: | 372/50; 372/96; 372/23; 372/102 |
| Current International Class: | H01S 319; H01S 308 |
| Patent References Cited: | 4885753 December 1989 Okai et al. 4980895 December 1990 Nishimura 4993036 February 1991 Ikeda et al. 5077752 December 1991 Tada et al. 5091916 February 1992 Cimini, Jr. et al. 5452318 September 1995 Makino et al. 5936994 August 1999 Hong et al. |
| Other References: | H.M. Stoll et al., "Multiply Resonant Distributed-Feedback Lasers", IEEE J. Quantum Elect., vol. QE-12, No. 1, pp. 53-57, Jan. 1976. "Coupled-mode theory of distributed feedback lasers", J. Appl. Phys., vol. 43, No. 5, pp. 2327-2335, 1972. (May). "A/4-shifted InGaAsP/InP DFB lasers",IEEE J. of Quantum Electronics, vol. QE-22, No. 7, pp. 1042-1051 (1986). (Jul.). "Sahlen, O., et al, A Robust WDM Network Laser Source: The DFB-Cascade Laser", Proceedings of the Optical Fiber Conference 1997 (OFC '97), Dallas, USA, Feb. 16-12, 1997, OSA Technical Digest Series, vol. 6, pp. 235-236. LU, H., et al, "Dynamic Properties of Partly Gain-Coupled 1.55 uM DFB Lasers", IEEE Journal of Quantum Electronics, vol. 31, No. 8, Aug. 1, 1995, pp. 1443-1450. Flanigan, B.J., et al, "Mode Selection in Complex-Coupled Semiconductor DFB Lasers", Electronics Letters, vol. 31, No. 12, Jun. 8, 1995, pp. 977-979. |
| Primary Examiner: | Bovernick, Rodney |
| Assistant Examiner: | Stahl, Michael J. |
| Attorney, Agent or Firm: | Donnelly, Victoria |
| رقم الانضمام: | edspgr.06104739 |
| قاعدة البيانات: | USPTO Patent Grants |
| الوصف غير متاح. |