Abstract

We report on the design and realization of a three-port tunable filter by collimating the input signals onto a multiplayer interference, thin film band pass filter. The tuning of the central wavelength of the pass band is achieved by changing the incident angle of the collimated beam on the filter. A specially designed retro-reflection structure formed by the TFF and a reflection mirror keeps the reflected, express signals invariant in space while the filter is tuned. During the filter tuning, the lateral offset of the transmitted add/drop signal is also compensated through a compensator synchronized to the TFF tuning, which cancels the walk-off of the transmitted beam.

© 2005 Optical Society of America