| 摘要 |
PROBLEM TO BE SOLVED: To prevent an optical heterodyne OFDR device from being affected by the disturbance. SOLUTION: Multiplexed light of part of measuring light P emitted from a wavelength variable light source 21 and reference light Pr emitted from a reference light source 24 is divided into two. One Pa1 of them is provided to a measuring object 1, the difference of predetermined frequency is provided between return light Pb from the measuring object 1 and the other light Pa2 by a signal generator 27 and a frequency shifter 28, and they are multiplexed. A first light component Pf, a component of measuring light, formed of light having the difference from the multiplexed light Pe by the predetermined frequency is separated from a second light component Pg, a component of the reference light, formed of light having the difference by the predetermined frequency, and they are made to come into photoelectric convertors 32 and 33, respectively. In a lock-in amplifier 35, a first beat signal Ef of the predetermined frequency output from the photoelectric convertor 32 is synchronously detected with a second beat signal Ef of the predetermined frequency output from the photoelectric convertor 33, and orthogonal components X and Y required for calculation are obtained. COPYRIGHT: (C)2008,JPO&INPIT
|
