LASER DOPPLER VELOCIMETER

摘要

PROBLEM TO BE SOLVED: To provide a scan laser Doppler velocimeter (LDV) smaller than the conventional one.SOLUTION: A sensor includes: first and second array waveguide type diffraction gratings having a phase variable region in which path lengths of waveguides adjacent to a part of an array waveguide are substantially equal to each other; N sets of output ports configured by arranging, in two columns, N first grating couplers connected to N (N is integer of two or more) light output waveguides of the first array waveguide type diffraction grating and N second grating couplers connected to N light output waveguides of the second array waveguide type diffraction grating; and a receiver for receiving scattered light. Each of the array waveguide type diffraction gratings includes (N-1) tapered liquid crystal layers that are formed across the phase variable region and function as an upper cladding layer of the waveguide. A laser Doppler velocimeter including the sensor is also provided.