Fabrication and analysis of integrated optic modulators in multiple quantum well gallium arsenide

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1992

OSTI ID:5585557

Cites, J S

This is the first report of single mode waveguide fabrication in multiple quantum well gallium arsenide/aluminum gallium arsenide (GaAs/AlGaAs) using reactive-ion etching with a CCl[sub 2]F[sub 2]/O[sub 2] plasma. Also, two techniques have been developed to perform this etching with a self-aligned electrode mask. Reactive-ion etched waveguides are compared to chemically etched waveguides through propagation loss measurements and guided mode structure as a function of waveguide geometry. A numerical waveguide model based on the effective index method for 3-D waveguides is developed to yield optical field profiles and propagation constants. This model is compared to the experimental data. This is also the first report of integrated optic waveguide Mach-Zehnder modulators and directional coupler modular/switches in this same multiple quantum well material system. The high bulk index and strong excitonic electrofraction of this material results in compact, high efficiency devices. The Mach-Zehnders are fabricated by chemical etching and are operated in single drive and push-pull mode, yielding a voltage-length product as low as 4.4 V[center dot]mm. The directional couplers are fabricated by reactive-ion etching with a novel step-etch masking technique which enhances evanescent coupling without increasing bending loss in the branching waveguides. The passive waveguide model is modified to include the electro-optic effect, and from this, models are developed for the Mach-Zehnder and the directional coupler to predict the modulation transfer curves as a function of applied voltage.

• Research Organization: Alabama Univ., Huntsville, AL (United States)
• OSTI ID: 5585557
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360601 -- Other Materials-- Preparation & Manufacture
440600* -- Optical Instrumentation-- (1990-)
47 OTHER INSTRUMENTATION
ALUMINIUM ARSENIDES
ALUMINIUM COMPOUNDS
ARSENIC COMPOUNDS
ARSENIDES
DATA
ELECTRICAL EQUIPMENT
ELECTRO-OPTICAL EFFECTS
EQUIPMENT
ETCHING
EXPERIMENTAL DATA
FABRICATION
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
INFORMATION
INTERFEROMETERS
MACH-ZEHNDER INTERFEROMETER
MATERIALS
MATHEMATICAL MODELS
MEASURING INSTRUMENTS
NUMERICAL DATA
PLASMA
PNICTIDES
SEMICONDUCTOR MATERIALS
SURFACE FINISHING
SWITCHES
WAVEGUIDES