| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem that, in a laser device using a polarization bistable VCSEL, exact temperature detection is difficult by using an external element, although a known method is to perform temperature regulation by supervising the temperature change using a temperature sensor, since a bistable region has quality in which the side of large injected current is shifts to the side of low current, so that the relative intensity ratio of the polarization output of two laser output directions is varied, when the bistable region is varied by the temperature change of an active layer, and the temperature rises larger than a predetermined temperature (normal state). SOLUTION: The semiconductor laser device always detects the optical output from one of two-direction polarizations and, if the optical output is varied, feed back the varied amount to a driver of the semiconductor laser. If the temperature rises, the light amount of the polarization oscillated in the side of low injected current becomes small. Conversely, if it is in the case where the polarization oscillated in the side of large injected current is monitored, the light amount become large. Normal state is maintained by feeding back the change and making the monitored light amount to become the original amount. COPYRIGHT: (C)2009,JPO&INPIT
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