Nonperipheral cleaved facet fabrication technique

A new technique for forming nonperipheral cleaved facets on GaAs epilayers for hybrid optical integration is demonstrated. Local photoelectrochemical etching is used to form an undercut region under the epilayer structure. The undercut region is then cleaved by subsequent ultrasonic agitation. Undercut widths of 70-170 μm/spl plusmn/5 μm are obtained at a bias voltage of 2 V and laser powers of 200-600 μW. Optical measurements show that these facets have minimal (0.4 dB) excess loss. A thin-film polarizer is inserted into the groove to test facet performance; the test shows a minimal degradation of the extinction ratio (<0.3 dB) over its free-space counterpart.