US 7,609,386 B2
Optical characteristic measuring apparatus
Takaaki Hirata, Tokyo (Japan); and Minoru Maeda, Tokyo (Japan)
Assigned to Yokogawa Electric Corporation, Tokyo (Japan)
Filed on Nov. 24, 2008, as Appl. No. 12/277,032.
Application 12/277032 is a division of application No. 11/443344, filed on May 31, 2006, granted, now 7,538,885.
Claims priority of application No. P.2005-159061 (JP), filed on May 31, 2005; application No. P.2005-163825 (JP), filed on Jun. 03, 2005; and application No. P.2005-171310 (JP), filed on Jun. 10, 2005.
Prior Publication US 2009/0079991 A1, Mar. 26, 2009
Int. Cl. G01B 11/02 (2006.01)
U.S. Cl. 356—492  [356/485] 8 Claims
OG exemplary drawing
 
1. An optical characteristic measuring apparatus for measuring an optical characteristic of a measuring object, the optical characteristic measuring apparatus comprising:
a first wavelength variable light source which sweeps a wavelength of a first input light and outputs the first input light to an interference section;
a second wavelength variable light source which sweeps a wavelength of a second input light and outputs the second input light to the interference section, frequencies of the first input light and the second input light being different from each other and polarized states of the first input light and the second input light being perpendicular to each other;
the interference section which multiplexes and inputs the first input light and the second input light to the measuring object, makes output light from the measuring object interfere with at least one of the first input light and the second input light, and outputs a plurality of interference lights;
a detecting section for detecting a frequency difference of the first input light and the second input light from the first wavelength variable light source and the second wavelength variable light source; and
a control section for controlling a frequency difference of the first wavelength variable light source and the second wavelength variable light source based on the frequency difference detected by the detecting section.