Other

Primanex Corporation

Gemfire Corporation

Lee Lisheng Huang

Shizhuo Yin

Daxin Liu

Hongdu Liu

William K Bischel

Michael J Brinkman

Tony C Kowalczyk

David Main

A thermo-optic switch is operated in a novel near-impulse mode in which the drive pulse width is shorter than twice the diffusion time of the switch. The drive pulse width is less than the rise time of the steady-state optical response and also less than the rise time of the deflection efficiency response to the applied drive pulse. The drive pulse can further include a sustaining segment following the initial short pulse segment, if it is desired to maintain the switch in an ON state for a longer period of time. A number of additional techniques are described for further reducing the response time of the switch. An array of thermo-optic switches operated in this manner can form a display which, due to the fast individual switch rise times, can operate at an overall fast refresh rate.

Thermo-optic switch having fast rise-time

Randomly polarized light impinges upon a birefringent crystal, is split into orthogonal polarization components and emerges from the crystal separated by a walk-off distance. The light beams then impinge on polarization rotators that cause a rotation of the plane of polarization by &plus;45&deg; and &minus;45&deg;. The light then encounters a variable polarization rotator in which the plane of polarization is rotated through a angle that varies in response to an externally-applied control signal. The maximum operating range (0 to 100% attenuation) is achieved when the variable rotator is capable of rotations in the range &plusmn;45&deg;. A second birefringent crystal functions as a beam displacer. The beams encounter two wave plates configured to produce rotation angles of 0&deg; and 90&deg; followed by a retroreflector. The reverse traverse of the attenuator causes the light to emerge at an output port attenuated in intensity.

Variable optical attenuator

The present invention relates to the use of magnetic materials in combination with magneto-optic materials to improve performance of Faraday rotator devices by enhancing the latching capability and reducing the driving current. Semi-hard magnetic materials are advantageously used in connection with some embodiments of the present invention. Placing such semi-hard magnetic materials in proximity with the magneto-optic material enhances latching and reduces the drive current required to cause switching. Encompassing both the magneto-optic material and the semi-hard magnetic material further reduces drive current requirements and enhances latching by reducing leakage of the magnetic field from its generation within the coil to the magneto-optic material. Some embodiments further include soft or semi-hard material encompassing the coil.

Faraday rotator

The present invention relates to optical switches in which switching occurs by changing the rotation of the plane of polarization by application of an externally applied control signal, particularly to magneto-optical switches controlling the port by which light emerges from the switch by externally-applied magnetic fields. The switches of the present invention function for randomly polarized input light, producing similarly randomly polarized light at the appropriate output port. Specific embodiments relate to 1&times;2 and 1&times;4 switches in both single pass and dual pass embodiments. Single pass embodiments are switches in which light passes through the optical components in one direction emerging at the appropriate output port depending on the desired switching. Dual pass embodiments are switches in which the light makes a forward and reverse traverse of the switch with total reflection. Dual pass switches typically reduce crosstalk without increasing the size of the switch. Single pass embodiments using two Faraday rotators are also disclosed for reducing crosstalk.

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Sunnyvale, CA, United States of America

Lee Lisheng Huang