SEMICONDUCTOR LIGHT EMITTING DEVICE

PURPOSE:To solve a problem of increasing the number of steps of assembling a semiconductor light emitting device and a problem of forming an end face by etching by providing an optical guide coupled optically with a laser diode, and forming a photodetector at least on part of the guide to monitor a laser light. CONSTITUTION:A first optical guide 2 for forming a resonator of a laser diode and a second optical guide 3 optically coupled with the guide 2 and having an electrically separating part 8 from a laser diode side are provided, and a photodetector is formed at the side 3' separated by the part 8 of the guide 3. For example, a double hetero structure is formed on a wafer 1 to form the guide 2 for forming a laser resonator and the photodetecting guide 3 optically coupled relatively weakly with the guide 2. Then, part of the guide 3 is etched until it penetrates an active layer 5 to form an electric isolator 8. A P-type electrode 9 is formed at the separated side 3, of the guide 3, an N-type electrode is formed at the side of an n type GaAs substrate 11, and laser ends ELD, ELD' are formed by cleaving.