Mvm Electronics, Inc.

University of California

Harris Corporation

Manhar L Shah

John D Crow

Shyh Wang

William D Hunt

A high-speed high-isolation fiber-optic matrix switch using only one acousto-optic device with phased array transducers is disclosed. Previously disclosed fiber-optic switches either required spatially separated more than one acousto-optic devices making them complex, hard to align and expensive or could not achieve high-isolation and low-insertion loss performance. A simple structure of 2&#xd7;2 fiber-optic matrix switch with one phased array transducer as disclosed here is expected to make acousto-optic based fiber-optic switches more attractive than similar MEMs based switches. Use of shared lens instead of individual lenses at the input and output fiber array is expected to further reduce complexity and cost of the acousto-optic based fiber-optic switches.

Fiber-optic matrix switch using phased array acousto-optic device

Acousto-optic(AO) devices having a sectioned optical transducer with a side passing optical beam forming an acousto-optic interaction plane, an electrode pattern on the transducer, and oblique demarcation cuts in the electrode pattern which are not normal to the acousto-optic interaction plane. The oblique cuts are at an angle oriented between 5 to 85 degrees, preferably approximately 45 degrees, with respect to the normal to the acousto-optic interaction plane. The oblique demarcation cuts eliminate side-lobes and ghost images in an acoustic field generated by the transducer. The electrode pattern shapes can be diamond, a truncated Gaussian, cosine, square, rectangular, circular, and elliptical. Acousto-Optic Modulators (AOMs). The types of AO devices include: Acousto-Optic Beam Deflectors (AOBDs), Bragg Cells (BCs), Acousto-Optic Tunable Filters (AOTFs), Acousto-Optic Frequency Shifters (AOFSs), and Acoust-Optic Correlators (AOCs).

Suppression of ghost images and side-lobes in acousto-optic devices

An acousto-optic polychromatic light modulating apparatus employs an acousto-optic medium, and a single piezoelectric transducer, which is driven by a plurality of frequency components, the intensities of which are controlled in response to input electronic data, to produce a color-modulated diffracted polychromatic output beam. The acousto-optic medium and mode as well as acousto-optic interaction length and the geometry of the device are selected such that there is negligible acousto-optic interaction with a given frequency signal on all output optical beam colors except for the one assigned to that frequency, with a high degree of color convergence achieved over a wide wavelength range. The present invention can be used to increase the modulation rate of a polychromatic modulator by selecting the incident optical beam energy propagation direction to be nearly normal to the acoustic wave phase propagation direction with non-parallel tangents at the incident and diffracted optical wave-vector loci. It may also be incorporated within the laser cavity of a discrete line laser and in the laser cavity of a continuous band laser, thereby enabling the selection or tuning of one or more wavelengths simultaneously. The use of a multi-frequency input RF driver enables the laser to be tuned electronically at high speed, without mechanical movement of any physical components.

Acousto-optic polychromatic light modulator

An interferometric spectrum analyzer employs a pair of Bragg cells arranged in an optically cascaded configuration such that both the signal beam and the reference beam travel along a common optical path. The beam-modifying properties of the Bragg cells are such that within a prescribed bandwidth of operation, the deflection properties of the respective cells are frequency complementary, namely different frequencies applied to the respective cells deflect the beam passing therethrough along the same optical path, to produce a beat frequency at the Fourier transform plane. In accordance with a first embodiment, complementary deflection action is achieved by using Bragg cells having respectively different acoustic velocites. In a second embodiment, each Bragg cell has the same acoustic velocity. The deflection/frequency complementary effect is obtained by the use of a birefringent material prism interposed between the Bragg cells, which produces angular deviation that depends upon the polarization and the direction of propagation of light passing through the prism.

Interferometric acousto-optic spectrum analyzer

Wave propagation in thin film optical waveguides using gyrotropic or anisotropic material in either the substrate or adjacent top layer with respect to the thin film waveguide is analyzed and a mode converter capable of converting TE to TM or TM to TE polarization is disclosed. Several mode converters constructed in accordance with the present invention are set forth. Also disclosed are other optical circuit elements constructed from such mode converters including a gyrator, isolator, an optical switch, and a non-destructive optical readout for magnetic memories.

Polarization converter and circuit elements for use in optical waveguides

For widening the temperature range of a reflective array device configured on a substrate having an anisotropic temperature coefficient of delay, such as ST-quartz material, so that the signal strength does not decrease appreciably as the temperature of the device is changed over a broad range, the structural shape of the reflective array is configured such that the reflection angles of the discontinuity-creating surface structure vary across the reflecting edges of the discontinuity stripe (e.g. groove or rib) pattern. In one embodiment, the stripe pattern of the grating may be varied so that the reflection angles vary for alternating stripes. In another embodiment, opposite edges of a stripe may be non-parallel so that the reflection angles vary for each stripe. It is also possible to amplitude weight the frequency response characteristic of a grating by controlling the physical structure of the individual stripes of which a grating pattern is formed. The use of a dot array configuration is especially advantageous in this regard since amplitude weighting can be achieved simply by controlling the dot array density of each stripe, implemented in a straightforward manner by suitable design of the grating mask.

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Melbourne Beach, FL, United States of America

Manhar L Shah