Incoherent frequency modulated cw optical reflectometry with centimeter resolution

An incoherent, frequency modulated continuous wave optical reflectomer is described which utilizes a broadband LiNbO(3) electrooptic modulator and slow photodiode for optical downconversion and detection, and a waveform recorder for digital spectrum analysis of the incoming signal. A two-point resolution of 6.8 cm in fiber is achieved. The dynamic range, defined as the location of the system noise floor relative to the maximum producible signal, is 50-dB optical.