of the surface light emitting device and a second region of the surface light receiving device are arranged in a direction approximately perpendicular to the layering direction the first region is electrically separated from the second region substantially and the first spacer layer in the first region and the first spacer layer in the second region are subjected to different oxidization including non oxidization respectively such that resonators composed of the first semiconductor multi layer mirror and the first spacer layer in the surface light emitting device and the surface light receiving device have different wavelength dependencies of reflectivity respectively application_number US 4631902 A description embodiments of an optical semiconductor apparatus of the present invention will be described by reference to fig3 to 8 a first embodiment will be described by reference to fig3 and 4a to 4 e the first embodiment uses a surface emitting laser as the surface light emitting device and a resonance type p i n photodiode as the surface light receiving device a fabrication method of the first embodiment can be performed in the following manner initially a first n type semiconductor multi layer mirror 103 of 22 5 pairs of n al 0 9 ga 0 1 as n al 0 1 ga 0 9 as an active layer or an absorptive layer 105 a second p type semiconductor multi layer mirror 107 of 17 pairs of p al 0 9 ga 0 1 as p al 0 1 ga 0 9 as a spacer layer 109 and a third p type.