Fiber based modulated pulsed source for microwave photonic lidar applications

The proposed high power green laser source with RF-modulated pulses will enable a new class of remote sensing instruments capable of achieving precise information from environments dominated by backscatter signals. Current remote sensing technologies lack capability to identify and discriminate objects under real-time environmental conditions. A hybrid lidar-radar system consisting of a pulsed laser is modulated at RF frequencies is capable of extracting meaningful data from the high intensity backscattered light in the water. A 500 kHz pulsed, fiber-amplified laser is proposed for the laser source. The pulse envelope is modulated via an electro-optic switch from 500 MHz to >1 GHz. The average power is amplified to several watts using a multi-stage Yb-doped fiber amplifier. In order for effective transmission through water, the 1064 nm radiation is frequency converted to 532 nm using either periodically poled stoichiometric lithium tantalate (SLT) or potassium titanyl phosphate (KTP). The all fiber design using a Yb-doped fiber amplifier, an EO switch and PPSLT or PPKTP ensures highly efficient and rugged performance. In addition to enabling a major advance in remote sensing within the littoral zone, the hybrid source will find direct application in involving highly obscured environments such as dust, smoke or moisture-laden environments.