Patent ID: 7030975

Claim:
An optical time domain reflectometer configured to sample a selected optical characteristic in a fiber optic transmission line, comprising: an optical source configured to repetitively emit first optical signals into a terminal portion of the fiber optic transmission line and a time delay unit operable to generate second optical signals suitably time-delayed relative to the first optical signals corresponding to the repetitive emissions; an optical receiver configured to detect reflected optical energy at the terminal portion of the fiber optic transmission line and generate reflected signals therefrom; a mixer operatively coupled to the optical receiver and to the optical source and adapted to receive the reflected signals and to receive the time delayed second optical signals and to generate a product waveform from the reflected signals and the time-delayed second optical signals; and a processor operatively coupled to the mixer that receives the product waveform to process the waveform to generate a value based on the sampled characteristic.