Abstract: A fiberoptic-coupled free-space variable delay line is provided wherein the phase adjustment of the signal can be accurately set. A microscope-objective lens collimates a signal beam which is received by a focusing lens. The focusing lens is provided on an adjustable carrier to allow one to accurately adjust the distance travelled by the collimated signal base and thereby accurately adjust the off-set. A plurality of these variable delay lines can be arranged to form a multiplexer. If the threads on each drive rod moving a carrier are different, the carrier can be adjusted to accommodate changes in frequency of the signal.

Abstract: An opto-electronic XOR gate includes a pair of diode type light sources connected back to back in parallel by a pair of input leads to which first and second electronic logic signals are applied. With only one logic signal in the high state, one of the diode-type light sources is forward biased while the other is reverse biased. With both logic signals high or low neither diode-type light source emits. A two to one fiber optic combiner (FOC) provides a single optical output which is on only when only one electrical signal is high. If an electronic output is desired, a single photodetector converts the output of the FOC to an electronic logic signal. For performing the exclusive OR operation on optical input signals, a pair of photodetectors and buffer amplifiers and connected to the input leads. For 10 to 12 GHz switching speeds laser diodes are used as the diode-type light sources. When lower switching speeds are satisfactory, light emitting diodes can be used as the diode-type light sources.

Abstract: Compressive, multiplicative electrical-optical system for testing high-speed, large scale logic devices. The output signals of the device are changed into optical signals which are applied to optical guided-wave light intensity modulators. Electrical reference signals of the desired, or correct, outputs are applied to the modulators to control the light passing through the modulators. The system provides a product of the actual output signal and the complement of the electrical reference signal, and a product of the complemented optical output signal and the uncomplemented electrical reference signal. The light output from the modulators during the formation of the two products is observed, with a detection of light from either product indicating that an error exists in an output channel of the device. Parallel, or simultaneous, product formation is provided in one embodiment, and sequential, or time spaced product formation, is provided in another embodiment.

Abstract: An optical processing system performs matrix-matrix, matrix-vector, and vector-vector multiplication. Element product formation is accomplished by the time integration of a detector array which converts light signals into electrical signals. Inner products are formed by the spatial integration of a cylindrical lens which focuses modulated light onto the detector array. Modulation of the light is accomplished by bit-serial modulation of the light sources with one element value in twos complement form, and by bit-serial modulation of an acousto-optic cell by the other element value in twos complement form. A multi-channel systolic embodiment permits a complete vector quantity formation without the need to enter modulation data separately for each inner product of the vector.

Abstract: An optical processor suitable for matrix-vector multiplication. Coherent light passes through an acousto-optic cell modulated by the elements in the rows of the matrix. This light progresses through a lens system to a magneto-optic cell which is modulated by the column elements of the vector. The light passing through the magneto-optic cell is converged by a spherical lens onto a single optical-to-electrical converter, whose output is applied to an analog-to-digital converter. After conversion to digital values, the result is converted from mixed binary to pure binary form.

Abstract: An optical system for testing the operation of very high speed logic devices. Output signals from the device being tested are loaded into a spatial light modulator while running at normal clocking frequencies. After being fully loaded, a laser light source is pulsed to send a short light signal through the spatial light modulator and onto a light detector array. The spatially modulated light, which is imaged upon the detector array, corresponds to the bit stream of data from the output of the device under test. According to one embodiment, the modulated signal is compared to stored binary values by conventional logic circuits. According to another embodiment, a second spatial light modulator is used to form a coinciding image on the same detector array. This second image corresponds to the complement of the correct output signal.