Itt Defense Communications, a Division of Itt Corporation

Itt Corporation

Alcatel USA

Itt Defense Communications

Anthony P Baker

A time standard assembly for a global positioning system (GPS), such as for a space vehicle, has a natural-frequency atomic frequency standard (NAFS) which is operated at its natural resonant frequency in order to output an upset-proof natural frequency signal. The assembly includes a frequency synthesizer unit (FSU) and microprocessor data unit (MDU) which are hardened by combining them together and enclosing them in one integral unit which is shielded from the electromagnetic pulse of an upset event. Multiply redundant NAFS, FSUs, and MDUs are used to improve reliability and for maintaining units on-line and in standby. A dithered clock frequency signal is generated by the FSU according to a dither algorithm performed by the MDU, and the MDU generates encoded clock data using the dithered clock frequency signal. The MDU includes an upset recovery mechanism for resetting its registers and counters using the upset-proof natural frequency signal from the NAFS upon detecting the occurrence of an upset event.

Time standard assembly with upset protection and recovery means

A fail-safe port apparatus includes a low loss liquid crystal optical switching device providing first and second light paths, the first path providing a failure, or default, mode path and the second path providing an operating mode.

Fail-safe port for use with an optical fiber

A liquid crystal wave division device includes first and second polarization changing cells, the polarization changing cells utilize homogeneously aligned nematic liquid crystal material to effect the change of polarization of a preselected frequency portion of a multifrequency incident light beam.

Liquid crystal wave division device

A liquid crystal switching device includes first and second polarization reorienting cells disposed such that a polarized component of an incident light beam is incident normal to the cell.

Liquid crystal switching device

A liquid crystal switching apparatus includes a plurality of juxtaposed liquid crystal switching devices, each such device being capable of selectively reorienting the polarization of a polarized light beam component incident thereupon.

Liquid crystal switching apparatus

An optical switching device includes first and second polarization changing cells, the polarization changing cells utilize twisted nematic liquid crystal material to effect the change of polarization. The resultant device exhibits reduced cross talk between the output ports thereof and requires less voltage to effect the switching of the output beam therebetween.

Optical switching device

A collimator includes a transparent base member defined by a planar surface and a spherical reflecting surface and includes an opening therein whereby an optical fiber may be terminated in the focal plane of the spherical reflecting surface.

Optical fiber collimator/switch including liquid crystal polarizing

A method for fabricating a liquid crystal optical cross point switching matrix includes the steps of forming a plurality of pedestals, each pedestal defining one half of a liquid crystal optical switching device that operates independent of critical angle alignment of the optical beams associated therewith.

Method of fabricating a liquid crystal optical cross point switching

A liquid crystal switching device utilizing the Brewster angle includes a Brewster angle polarizer disposed such that an incident light beam of the device impinges thereon at an angle approximately equal to the Brewster angle.

Liquid crystal switching device using the brewster angle

A liquid crystal optical cross point switching device includes first and second liquid crystal optical switches each characterized as having optical fibers spaced apart by liquid crystal material over a length thereof along which the cores of the fibers are exposed.

Liquid crystal optical cross point switching device

A liquid crystal optical switching device includes first and second transparent members configured to minimize both the path length and the number of internal reflections of a light beam traversing the device.

Liquid crystal optical switching device having minimized internal light

A liquid crystal optical switching device includes a plurality of ports each having associated therewith a blind hole receiving an optical fiber that is secured subsequent to the alignment thereof. The switching device is fabricated from inexpensive material and includes a minimum of optically flat surfaces.

Liquid crystal optical switching device

A liquid crystal optical switching device having reduced crosstalk includes a liquid crystal beam splitter for splitting incident light into polarized components thereof and a liquid crystal optical switch for directing those components to either a first or a second output port.

Liquid crystal optical switching device having reduced crosstalk

A liquid crystal optical switching device that is independent of critical angle accuracies in the manufacturer and operation thereof includes an exposed fiber optic proximate the liquid crystal material.

Liquid crystal optical switching device with integrally attached optical

An optical interface apparatus includes a liquid crystal carrier light beam modulator and a liquid crystal demodulator.

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New York, NY, United States of America

Anthony P Baker