DIGITALLY TUNABLE WAVELENGTH FILTER AND LASER

A novel nonmechanical, digitally tunable, polarization insensitive and optically transparent wavelength filter using holograms electro-optic ally written on a ferroelectric liquid crystal (FLC) spatial light mod ulator (SLM) has been constructed and operated to tune to discrete wav elengths spaced by 1.3 nm. The filter has been incorporated in a ring laser which is tunable over a range of 38.5 nm across the erbium windo w, giving output powers of 10 mW. Both wavelength filter and tunable l aser are suitable for wavelength division multiplexing (WDM) applicati ons.