Displacement measurement using photo-electromotive-force effects in semi-insulating CdZnTe with linearly chirped lasers

Summary form only given. Coherent frequency domain reflectometry has recently been applied to characterize communication optical fiber cables by measuring coherently optical signals reflected backwards from the break-off point in an optical fiber. Instead of counting the delay time suffered by laser pulses, coherent frequency domain reflectometry translates target distance information onto frequency domain, which can then be retrieved using electronic spectrum analyzers and/or Fast Fourier Transform calculations. It has also been demonstrated that photo-EMF effects found in semi-insulating semiconductors can be used to measure optical frequency differences, perform optical spectral analysis and monitor mechanical vibration. We present in the paper the experimental integration of photo-EMF optical frequency sensors with coherent time domain reflectometry, resulting in a compact and simple coherent optical range finder which produces an output photocurrent that can be linearly proportional to the displacement of the remote target.