| 摘要 |
PROBLEM TO BE SOLVED: To provide a miniaturizable speed meter capable of reducing power consumption, and detecting highly accurately a moving speed of a measuring object. SOLUTION: A second beam 8 emitted from the rear end surface of a laser diode 1 is reflected by a mirror 5b and enters a detection point 14a. On the other hand, a first beam 7 emitted from the front end surface of the laser diode 1 enters a diffraction grating 3. Hereby, zero-order diffracted light 7g by the diffraction grating 3 is reflected by a mirror 5a and enters the detection point 14a, and±1st-order diffracted light 7h, 7i by the diffraction grating 3 is reflected by mirror 5c, 5d and enters a detection point 14b. Scattered light from the detection points 14a, 14b is received by photodiodes 32a, 32b. A signal processing circuit part 10 calculates the frequency deviation quantity of the scattered light based on outputs Sa, Sb from the photodiodes 32a, 32b. COPYRIGHT: (C)2005,JPO&NCIPI
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