Hybrid integration of GaAs-based VCSEL array with amorphous silicon sensor

We describe an optoelectronic module incorporating a vertical-cavity surface-emitting laser (VCSEL) array with a semitransparent light monitor. The power monitor is a p-i-n amorphous silicon photodetector fabricated on glass. Sets of micromachined springs for electrical contacting are also fabricated in the same process on the same glass substrate. Hybrid packages are formed by pressing the compliant springs against individual contact pads of the GaAs VCSEL array in a flip-chip assembly process. The light sensor is aligned directly on top of the laser elements. Most of the laser light is transmitted through the sensor, yet a large dynamic range is maintained because of the sensors exceedingly low dark current.