Integrated laser device has insulating layers with opening between upper extrinsic and intrinsic semiconductor layers and intrinsic and lower extrinsic semiconductor layers of photodetector for monitor

摘要

A photodetector for monitor (160) integrated with laser device (110), absorbs partially light radiated from laser source. Insulating layers (194,192) with opening in their center region, are provided between extrinsic and intrinsic semiconductor layers (164,172) and between intrinsic semiconductor layer and lower extrinsic semiconductor layer (162) of photodetector for monitor, so that photoelectric current output due to spontaneous light irradiation is prevented. A laser device (110) comprises lower reflective layer (132), gain medium layer (142), high resistive layer (152) and upper reflective layer (134) which are sequentially laminated on substrate (112). A pair of electrodes (122,124) are respectively provided to rear end of substrate and on upper reflective layer. The photodetector for monitor (160) comprises lower extrinsic semiconductor layer (162), intrinsic semiconductor layer (172) and upper extrinsic semiconductor layer (164) which are sequentially formed on exposed surface of upper reflective layer. Another electrode (126) is laminated on upper extrinsic semiconductor layer such that center portion of upper extrinsic semiconductor layer is exposed to form laser window (182). The laser device irradiates light when current is supplied between electrodes (122,124). The photodetector for monitor partially absorbs the irradiated light and outputs detecting signal. Upper and lower insulating layers (194,192) having opening in center region, are respectively provided between upper extrinsic semiconductor layer and intrinsic semiconductor layer and intrinsic semiconductor layer and lower extrinsic semiconductor layer, so that photoelectric current output due to spontaneous light irradiation is prevented.