Achromatic optical phase shifter-modulator

We propose and demonstrate, theoretically and experimentally, a novel achromatic optical phase skifter-modulator based on a frequency-domain optical delay line configured to maintain zero group delay as variable phase delay is generated by means of tilting a mirror. Compared with previously reported phase shifter-modulators, e.g. based on the Pancharatnam (geometric) phase, our device is high speed and polarization insensitive and produces a large, bounded phase delay that, uniquely, is one-to-one mapped to a measurable parameter, the tilt angle. (C) 2001 Optical Society of America OCIS codes: 120.3180, 120.5060, 350.1370.