Patent ID: 8103138

Claim:
A tunable filter, comprising: an input optical fiber for launching an optical signal into the tunable filter; a collimator disposed for collimating light transmitted from the input optical fiber; a grating disposed for dispersing the collimated light according to wavelength in a dispersion plane; a first reflector disposed for reflecting at least a portion of the dispersed light to a second reflector; a second reflector disposed for reflecting the dispersed light back to the grating; a third reflector disposed for reflecting the transmitted dispersed light from the grating back to the grating, wherein then the second reflector reflects the transmitted dispersed light to the first reflector, the first reflector reflects the transmitted dispersed light back to the grating, the collimator receives the transmitted dispersed light from the grating and substantially focusing it to a focal point; and an output optical fiber disposed at the focal point for receiving the focused light; wherein one of the reflectors is rotated to selectively reflect the dispersed light having a predetermined wavelength.