Patent ID: 8107818

Claim:
A tunable filter comprising: an optical branching element for spatially dispersing an incident light for each of wavelengths in the incident light to output the dispersed lights and for making a selected reflected light be incident toward an incident direction of said incident light; a light focusing element for focusing the lights of respective wavelengths dispersed for each of wavelengths in said optical branching element on an identical plane with keeping a relative relationship of incident position; a mirror substrate which is provided in a movable state at a position on which belt-shaped lights from said light focusing element are focused, and includes a plurality of reflection regions different for each of the lights of wavelengths to be selected, wherein said reflection regions are arranged at an arbitrary position toward a direction different from a distribution direction of said belt-shaped lights; and a driver for moving said mirror substrate toward a direction different from the distribution direction of said belt-shaped lights.