Abstract: A fiber optic amplifier utilizes a crystal fiber of laser material to bidirectionally amplify light signals. This amplifier permits the application of both pumping illumination and the signal to be amplified to the end of the crystal fiber to avoid the disadvantages inherent in side pumping this fiber. End pumping is accomplished by taking advantage of the slow spontaneous fluorescence of the laser crystal to sequentially apply the pumping illumination and then the signal to be amplified to the crystal. This sequential application of signals is made possible through the use of a switchable coupler which allows light to be selectively coupled from either of a pair of input optical fibers to a single output optical fiber which is coupled to the crystal fiber. The pumping illumination is initially supplied to the crystal fiber to invert the ions within the crystal.

Abstract: A method of visually representing output data on a screen by deflecting a laser beam in both horizontal and vertical directions for scanning, and an indicating device for performing the above method. The laser beam is first divided into two polarized waves which are, after being modulated in accordance with the output data, combined into a first synthesized laser beam. The two polarized waves are alternately extinguished synchronously with a predetermined simple harmonic oscillation. The synthesized laser beam is then horizontally deflected by means of a sinusoidally oscillating mirror so that the angular displacement of the deflection oscillates in synchronism with the predetermined simple harmonic oscillation. The resultant deflected beam is again divided into two polarized waves, one of which is then inverted. The resulting two polarized waves are combined to obtain a second synthesized laser beam whose angular displacement in deflection is unidirectional at any phase.

Abstract: A laser pulse is injected into an unstable ring resonator-amplifier structure. Inside this resonator the laser pulse is amplified, spatially filtered and magnified. The laser pulse is recirculated in the resonator, being amplified, filtered and magnified on each pass. The magnification is chosen so that the beam passes through the amplifier in concentric non-overlapping regions similar to a single pass MOPA. After a number of passes around the ring resonator the laser pulse is spatially large enough to exit the ring resonator system by passing around an output mirror.

Abstract: Apparatus for scrambling and descrambling the video portion of TV signals is disclosed. The video portion of the TV signal is stored in a serial memory such as a charge coupled device. Scrambling is accomplished by shifting the end portion of the lines of video to the beginning by recirculating the data stored in the charge coupled devices for a portion of a line of the video signal. Two charge coupled devices are provided so that when the data stored in one device is being recirculated for scrambling the subsequent line can be stored in a second device. Descrambling is an inverse operation and is accomplished in essentially identical hardware.

Abstract: An electrical circuit that interrupts normal operation of a cable television channel selection box responsive to unauthorized entry into the box. A closure means is mounted about its periphery by a plurality of screw members that must be removed in a predetermined sequence to avoid disabling the box. A power source provides current through a bypass means in the form of a normally closed switch means as long as the closure means remains closed, but removal of a fastening means not associated with said bypass means prior to interruption of said current results in de-activation of the channel selection box.