An optical integrated circuit for time-division 2-D velocity measurement

An LiNbO/sub 3/ optical integrated circuit pigtailed with two single-mode fibres, which allows time-division two-dimensional velocity measurement, is discussed. To detect time-division multiplexed beat signals corresponding to velocity components v/sub X/ and v/sub gamma / of a moving object, a waveguide switch is integrated on a Z-propagating LiNbO/sub 3/ substrate of 28*7 mm/sup 2/ in addition to a waveguide interferometer with a frequency shifter. In the optical IC, either v/sub X/ or v/sub gamma / could be measured selectively with signal-to-noise ratio of 20 dB by driving an electronic gate placed after a photodiode in synchronization with the waveguide switch.<>