| 摘要 |
PROBLEM TO BE SOLVED: To facilitate control of a wavelength change of a semiconductor laser, and to reduce an effect of a transient response of a triangular wave vertex. SOLUTION: A physical quantity sensor has the semiconductor laser 1; a laser driver 4 for operating the semiconductor laser 1 to repeat at least the first oscillation period wherein an oscillation wavelength is monotonously increased continuously, the second oscillation period wherein the oscillation wavelength is monotonously decreased continuously, the third oscillation period wherein the oscillation wavelength is constant at the maximum value between the first oscillation period and the second oscillation period, and the fourth oscillation period wherein the oscillation wavelength is constant at the minimum value between the second oscillation period and the first oscillation period; and a measuring means (a current-voltage conversion amplifier 5, a filter circuit 6, a counting device 7, an operation device 8) for measuring the physical quantity of a measuring object from information of interference generated by a self-coupling effect between laser light and return light included in an output from a photodiode 2. COPYRIGHT: (C)2009,JPO&INPIT
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