An Integrated Waveguide Detector for Power Control in an InP Mach-Zehnder Modulator Based 10 Gb/s Transmitter

Integrated waveguide detector designs for optical power control in an InP Mach-Zehnder modulator based transmitter are described. By incorporating an InGaAs absorbing layer with a graded p-side hetero-junction, a power monitor that is insensitive to bias voltage, optical power and wavelength is achieved. Detailed two dimensional simulations of carrier transport under conditions of high optical power were fit to experimental data and clarify the carrier recombination mechanisms that degrade the device performance. Non-optimized versions of the power monitor have been used successfully to improve power stability in a 10 Gb/sec transmitter package, enabling a 0.2 dB power deviation over an ambient temperature range from 0 to 70degC