Narrow-band light source with acoustooptic tunable filter for optical low-coherence reflectometry

An electrically-tunable narrow-band light source with no moving parts is constructed for jaggedness-free optical low coherence reflectometry. The source incorporates a double-path acoustooptic tunable bandpass filter module whose two passbands automatically agree to within 0.2 nm during wavelength tuning from 1529-1568 nm. The source emits narrow-band light with an FWHM of 1.8/spl plusmn/0.1 nm, a power of >0 dBm and a suppressed background spectrum. The entire wavelength range can be swept electrically within 100 ms by using a variable RF source.