Patent ID: 6965479
Filing Date: 2005-11-15
Classification: G02B

Abstract:
1. An optical filter comprising: a first optical system which has a first beam splitter, splits light arriving at the first beam splitter through a first optical path into two light beams, and outputs the split light beams to different second and third optical paths, respectively; a second optical system which outputs light arriving after being output from the first beam splitter to the second optical path upon giving the light an intensity change with wavelength dependence and a phase change; and a third optical system which outputs, to the first beam splitter, light arriving after being output from the first beam splitter to the third optical path, wherein the third optical system outputs light given an intensity change with wavelength dependence and a phase change to the first beam splitter, said second optical system outputs light given an intensity change with wavelength dependence and a phase change to the first beam splitter, said third optical system outputs light given an intensity change with wavelength dependence and a phase change to the first beam splitter, and the first beam splitter splits the light arriving after being output from said second optical system into two light beams, outputs the light beams to the first optical path and a fourth optical path, respectively, splits the light arriving after being output from said third optical system into two light beams, and outputs the light beams to the first and fourth optical paths, respectively.