Abstract: A silicon nitride phased array chip based on a suspended waveguide structure, which includes a silicon nitride waveguide area and a suspended waveguide area. The silicon nitride waveguide area includes a silicon substrate, a silicon dioxide buffer layer, a silicon dioxide cladding layer and a silicon nitride waveguide-based core layer. The silicon nitride waveguide-based core layer includes an optical splitter unit, a first curved waveguide, a thermo-optic phase shifter and a spot-size converter. The suspended waveguide area includes a second curved waveguide and an array grating antenna.

Abstract: A laser velocimetry method and system are provided. In the method, an ultrashort pulse laser is subjected to temporal broadening, beam splitting and spectrum broadening in sequence to from a three-dimensional measurement space. When an object moves in the measurement space, a first signal light s_1, a second signal light s_2, a third signal light s_3 are generated, based on which velocity components vy, vx, and vx of the target object can be obtained, respectively, so as to obtain the velocity of the object in accordance with a formula of v=vx·i+vy·j+vz·k.

Abstract: A silicon nitride phased array chip based on a suspended waveguide structure, which includes a silicon nitride waveguide area and a suspended waveguide area. The silicon nitride waveguide area includes a silicon substrate, a silicon dioxide buffer layer, a silicon dioxide cladding layer and a silicon nitride waveguide-based core layer. The silicon nitride waveguide-based core layer includes an optical splitter unit, a first curved waveguide, a thermo-optic phase shifter and a spot-size converter. The suspended waveguide area includes a second curved waveguide and an array grating antenna.