Active solid-state devices (e.g. – transistors – solid-state diode – Incoherent light emitter structure – With reflector – opaque mask – or optical element integral...
Reexamination Certificate
2001-06-29
2003-11-18
Jackson, Jerome (Department: 2815)
Active solid-state devices (e.g., transistors, solid-state diode
Incoherent light emitter structure
With reflector, opaque mask, or optical element integral...
C372S045013, C372S050121
Reexamination Certificate
active
06649940
ABSTRACT:
FIELD OF THE INVENTION
The field of the invention is semiconductor quantum well lasers.
BACKGROUND OF THE INVENTION
Semiconductor lasers are the fundamental building block in compact optic and optoelectronic devices. Formed from Group III-V semiconductors, the semiconductor lasers emit laser light in response to electrical stimulation as electrons relax back to lower energy states and emit photons. Two conventional types of semiconductor lasers are buried heterostructure lasers (BH) and ridge waveguide (RW) lasers.
BH lasers are extremely effective at confining carriers. The lateral heterostructure of a BH also creates a large index step, which strongly confines the optical mode of the laser. Another result of the large index step, though, is the support of higher order modes. The higher order modes can give rise to beam instability, a large diffraction angle, and poor fiber coupling efficiency. A physically narrow BH device can defeat propagation of higher order modes, but provides a smaller available gain volume, higher optical power density at its facets, and larger diffraction angle of its emitted beam. Manufacturing narrower BH lasers also poses more difficult manufacture process control problems compared to otherwise similar wider devices. In general, the BH lasers are low threshold but high performance devices.
RW lasers can be made with a comparably smaller index step. The index step of an RW laser is controlled by controlling the depth of the ridge etch. RW lasers are easier to manufacture than BH lasers since the RW lasers require only a single crystal growth step. However, the RW lasers are less efficient than BH lasers. Due to unconfined spreading of carriers, a region outside of the ridge in an RW laser is also pumped leading to gain which is not effectively utilized. As a result, the threshold current of a RW laser can be twice as high as a comparable BH laser.
SUMMARY OF THE INVENTION
A semiconductor quantum well laser of the invention utilizes separate lateral confinement of injected carriers and the optical mode. A ridge waveguide is used to confine the optical mode. A buried heterostructure confines injected carriers. A preferred embodiment laser of the invention is a layered semiconductor structure including optical confinement layers. A buried heterojunction within the optical confinement layers is defined in a quantum well layer, and is dimensioned and arranged to confine injected carriers during laser operation. A ridge waveguide outside the optical confinement layers is dimensioned and arranged with respect to the buried heterojunction to confine an optical mode during laser operation. An index step created by the buried heterojunction is substantially removed from the optical mode.
REFERENCES:
patent: 5138626 (1992-08-01), Yap
patent: 5222095 (1993-06-01), Zediker et al.
patent: 6287884 (2001-09-01), Jie et al.
patent: 0566494 (1997-04-01), None
patent: 0651478 (1999-05-01), None
G.H. Thomson, P.A. Kirkby, “(GaA1)As lasers with a heterostructure for optical confinement and additional heterostructures for extreme carrier confinement,” IEEE J. Quant. Elect., vol. QE-9, No. 2, pp. 318-323, 1973.
M.C. Amann, “Waveguiding analysis of mushroom stripe laser diodes,” IEE Proc. vol. 135, No. 1, pp. 68-73, Feb. 1988.
J. Guthrie, G.L. Tan, M. Ohkubo, T. Fukushima, Y. Ikegami, T. Ijichi, M. Irikawa, R.S. Mand, J.M. Xu, “Beam instability in 980-nm-power lasers: Experiment and analysis,”IEEE Phot. Tech. Lett., vol. 6, No. 12, pp. 1409-1411, Dec. 1994.
M.L. Xu, G.L. Tan, R. Clayton, and J.M. Xu, “Increased threshold for the first-order mode lasing in low-ridge waveguide high power QW lasers,” IEEE Phot. Tech. Lett., vol. 8, No. 11, pp. 1444-1446, Nov. 1996.
S.P. Cheng, F. Brillouet, and P. Correc, “Design of quantum well AlGa-As-GaAs stripe lasers minimization of threshold current—application to ridge structures,” IEEE J. of Q. Elect., vol. 24, No. 12, Dec. 1988.
S.Y. Hu, S.W. Corzine, K.K. Law, D.B. Young, A.C. Grossard, L.A. Coldren, and J.L. Merz, “Lateral carrier diffusion and surface recombination in InGaAs/AlGaAs quantum-well ridge waveguide lasers,” J.Appl. Phys. vol. 76, No. 8, pp. 4479-4478, Oct. 1994.
S.L. Chuang,Physics of Optoelectronic Devices.New York: John Wiley & Sons, 1995, pp. 270-273.
G.P. Agrawal, Ed.,Semiconductor Lasers.New York: American Institute of Physics, 1995.
T.M. Cockerill, D.V. Forbes, J.M. Dantzig, and J.J. Coleman, “Strained-layer InGaAs-GaAs-AlGaAs buried-heterostructure quantum-well lasers by three-step selective-area metalorganic chemical vapor deposition,” IEEE J. of Q. Elect., vol. 30, No. 2, pp. 441-445, Feb. 1994.
Reithmaier, J.P., “Focused ion-beam implantation induced thermal quantum-well intermixing for monolithic optoelectronic device integration,” IEEE J. Sel. Top. Quantum Electron., vol. 4, No. 4, pp. 595-605, Jul.-Aug. 1998.
Grupen, M., Ravaioli, U., Galick A., Hess K., Kerkhoven, T., “Coupling the electronic and optical problems in semiconductor quantum well laser simulations,” Proc. SPIE—Int. Soc. Opt. Eng., vol. 2146, pp. 133-147, 1994.
Lage, H., Heitmann, D., Cingolani, R., Oestreich, M., “Linear and nonlinear optical properties of GaAs quantum wires-center-of-mass, excitonic and electron-hole plasma quantization,” Phys. Scr. vol. T (Sweden), vol. T45, pp. 206-209, 1992.
Kish, F.A., Caracci, S.J., Maranowski, S.A., Holonyak, N., Jr., Smith, S.C., Burnham, R.D., “Planar native-oxide Al-sub x/Ga/sub 1-x/As-GaAs quantum well heterostructure ring laser diodes,” Appl. Phys. Lett., vol. 60, No. 13, pp. 1582-1584, Mar. 1992.
Van Gieson, E., Meier, H.P., Harder, C., Buchmann, P., Webb, D., Walter, W., “High-performance GaAs/AlGaAs graded refractive index separate confinement heterostructure lasers grown by molecular-beam epitaxy on Si/sub 3/N/sub 4/masked substrates,” J. Vac. Sci, Technol. B. Microelectron. Process. Phenom., vol. 7, No. 2, pp. 405-408, Mar.-Apr. 1989.
Dzurko, K.M., Menu, E.P., Beyler, C.A., Osinski, J.S., Dapkus, P.D., “Temperature engineered growth of low-threshold quantum well lasers by metalorganic chemical vapor desposition,” Appl. Phys. Lett., vol. 54, No. 2, pp. 105-107, Jan. 1989.
Coleman James J.
Swint Reuel B.
Zediker Mark S.
Greer Burns & Crain Ltd.
Jackson Jerome
The Board of Trustees of the University of Illinois
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