Abstract: A ring laser is provided with at least one retroreflector external to the ring laser closed-loop path for redirecting energy extracted from one of the counterpropagating beams into the opposite traveling counterpropagating beam. The redirected energy is modulated so as to oppose the normal coupling between the counterpropagating beams which causes lock-in.

Abstract: Fiber optic rotary coupler apparatus is disclosed in which a light signal formed in a continuous ring in a plane is transmitted between a barrel and a surrounding sleeve within which the barrel is rotatably mounted. The light signal ring is produced by a light source and an associated light transmitting fiber wound on the barrel in at least one complete circular loop of a radius such that a portion of a light signal introduced into an end thereof is transversely radiated from the fiber. Light detector means, which may include a further optical fiber for transmitting light signals to a remote detector, is carried on the sleeve. In one embodiment, a plurality of optical and electrical signal channels are incorporated into a single device.

Abstract: Optical slip ring apparatus is disclosed in which radial light signals formed in a continuous ring are transmitted between a barrel and a surrounding sleeve within which the barrel is rotatably mounted. The ring of light signals is produced and detected respectively by a plurality of light emitting diodes and light detector means carried on the barrel and the sleeve. The light detector means may include an optical fiber bundle for transmitting light signals to a remote detector. In one embodiment, a plurality of optical and electromechanical slip ring channels are incorporated into a single device.