All-fiber multifunction continuous-wave coherent laser radar at 1.55 mu m for range, speed, vibration, and wind measurements

The design and performance of a simple, multifunction 1.55-mu m continuous- wave (cw) and frequency-modulated cw coherent laser radar system with an ou tput power of 1 W is presented. The system is based on a semiconductor lase r source plus an erbium-doped fiber amplifier, a polarization-independent f iber-optic circulator used as the transmit-receive switch, and digital sign al processing. The system is shown to be able to perform wind-speed measure ments even in clear atmospheric conditions when the visibility exceeds 40 k m. The aerosol measurements indicate the potential to use single-particle d etection for wind measurements with enhanced sensitivity. The system can pe rform range and line-of-sight velocity measurements of hard targets at rang es of the order of several kilometers with a range accuracy of a few meters and a velocity accuracy of 0.1 m/s by use of triangular-wave frequency mod ulation with compensation of the frequency-modulation response of the semic onductor laser. The system also demonstrates a capability for vibration sen sing. (C) 2000 Optical Society of America.