Fabrication and analysis of high-contrast InGaAsP-InP Mach-Zehnder modulators for use at 1.55-mu m wavelength

A high-contrast ratio, low voltage-length product, multiple quantum well InGaAsP-InP Mach-Zehnder interferometer is demonstrated and analyzed. An on/off ratio of over 40 dB and voltage-length product of 1.8 V-mm were measured, results which are superior to previous reports of similar MQW structures. Using the Lanczos-Helmholtz beam propagation method, we find that the linear and quadratic electrooptic coefficients for InGaAsP quantum wells are r = (3.9 +/- 1.7) pm/V and s = (5.0 +/- 1.5) x 10(-19) m(2)/V-2, respectively. We also demonstrate active optical alignment of the modulator guides using integrated waveguide light emitting diodes.