COUPLED QUANTUM WELL OPTICAL
INTENSITY MODULATOR FOR ENP BASED
CIRCUITS AND METHODS THEREFOR
 Inventors: Milson Silva, Sao Carlos, Brazil;
Peter R. Herczfeld, Philadelphia, Pa.;
Steven A. Malone, Eatontown;
Arthur C. Paolella, Howell, both of
 Assignee: The United States of America as
represented by the Secretary of the Army, Washington, D.C.
 Appl. No.: 242,933
 Filed: May 16,1994
 Int. CI.* H01L 29/205
 U.S. CI 257/14; 257/85;
257/96; 257/431; 257/615
 Field of Search 257/14, 84, 85, 94,
257/96, 103, 431, 615; 372/42, 96
 References Cited
U.S. PATENT DOCUMENTS
5,381,023 1/1995 Komatsu 257/85
J. E. Zucker et al., "Miniature Mach-Zehnder InGaAsP Quantum Well Waveguide Interferometer for 1.3 urn", IEEE Photon. Tech. Lett, 2, 32, 1990. E. Bigan et al., "Efficient Electroabsorption in InGaAsP/InGaAsP MWQ Optical Waveguide", Electron. Lett., 27, 1607, '91.
N. Debbar et al., "Coupled GaAs/AlGaAs Quantum Well Electro-absorption Modulators for Low Electric Field Optical Modulation", J. App. Phys., 65,383,1989. K. Nakamura et al., "Numerical Analysis of the Absorption and the Refractive Index Change in Arbitrary
[li] Patent Number: 5,428,225  Date of Patent: Jun. 27,1995
Semiconductor Quantum-Well Structures", IEEE J.
Quantum Electron., 28,1670, '92.
B. Broberg and S. Lindgren, "Refractive Index of In
GaAsP Layers and InP in the Transparent Wavelength
Region", J. Appl. Phys., 55, 3376, 1984.
J. E. Zucker et a!., "Quaternary Quantum Wells for
Electro-Optic Intensity and Phase Modulation at 1.3
and 1.55 urn", Appl. Phys. Lett., 54, 10, 1989.
G. M. Alman et al., "Refractive Index Approximations
from Linear Perturbation Theory for Planar MQW
Waveguides", IEEE J. Quantum Electron., 28, 650,
F. Fiedler and A. Schlachetzki, "Optical Parameters of InP-Based Waveguides", Solid-State Electron., 30, 73, 1987.
Primary Examiner—Mark V. Prenty
Attorney, Agent, or Firm—Michael Zelenka; William H.
An integrated optical intensity modulator. The modulator is an optical waveguide on a semi-insulating substrate and having a core layer for transmitting an optical signal. The modulator includes contiguous the core layer an active cladding which has a multicoupled quantum well structure. The multicoupled quantum well includes at least one pair of quantum wells separated by a barrier. The modulator further includes first and second additional claddings wherein the core layer and the active cladding are interposed between the additional claddings. A voltage source generates an electric field through the active cladding which varies the refractive index of the active cladding as a function of the strength of the electric field for modulating the optical signal.
22 Claims, 4 Drawing Sheets