SEMICONDUCTOR LASER DEVICE FOR REDUCING OSCILLATION WAVELENGTH VARIATION DUE TO TEMPERATURE VARIATIONS USING GAIN AND LOSS EQUALIZED ONLY ON SELECTIVE REGIONS

摘要

PURPOSE: A semiconductor laser device is provided to reduce oscillation wavelength variation due to temperature variations by equalizing gain and loss of the device only on regions where a reflective ratio decreases as the wavelength increases. CONSTITUTION: A semiconductor laser device at least includes an active layer(6), a clad layer(3,10), and a cross section for emitting light. A low reflective layer(16) is implemented on the cross section. The reflective ratio of the low reflective layer varies according to wavelength. A wavelength, where the reflective ratio of the low reflective layer is minimized, lies on a wavelength portion longer than a wavelength where the gain of the semiconductor laser device is maximized. Gain and loss of the semiconductor laser device are set to be equal to each other only on regions where the reflective ratio decreases as the wavelength increases.