| 摘要 |
PROBLEM TO BE SOLVED: To detect/determine a wavelength of a laser beam emitted from an external-resonator-type semiconductor laser using a simple structure, and furthermore suppress injection of laser light in an disabled mode. SOLUTION: The device has a reflection element that receives at least part of a laser beam emitted from an external-resonator-type semiconductor laser, and emits reflected light, causing different light intensity distribution corresponding to a striped image; a photodetector that detects light intensity of the reflected light from the reflection element at least two light receiving positions; and a determination circuit that obtains a differential value between detected signals in the at least two light receiving positions, and determines a wavelength of the laser beam based on the differential value, wherein the at least two light receiving positions are disposed in a direction along which the stripes are aligned. COPYRIGHT: (C)2006,JPO&NCIPI
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