Fail-safe acousto-optic t-couplers for optical communication networks

Abstract From the Canadian patent

A fail-safe optical T-coupler for coupling a local terminal having at least one light source and at least one photodetector to a segmented optical data bus comprises an optically transparent acousto-optic cell, a pair of collimating lenses For coupling adjacent segments of the data bus to opposite ends of the acoustic-optic cell symmetrically with respect to the optical axis of the coupler so that there is a fail-safe path for transmitting remotely injected light from one segment of the bus to the next and at least one acoustic driver, for coupling acoustic bulk waves into the acousto-optic cell to selectively establish or intensify an ultrasonic grating along an acoustic axis. For …