Optiswitch Technology Corporation

USA As Represented by Secretary of the Navy

The Titan Corporation

Omnipulse Technology Corporation

David M Giorgi

Tajchai Navapanich

Jay Philippbar

Douglas M Weidenheimer

John D Sethian

James Long

Oved S F Zucker

A pulsed diode light source driver includes a variable output power supply, an output capacitor, a switchable linear current driver, a temperature sensor, a conditioning circuit, and a voltage monitor. The temperature sensor monitors the temperature of the capacitor while the voltage monitor circuit monitors the output voltage level. The conditioning circuit and the voltage monitor cooperatively control the output voltage of the variable output power supply, so that temperature-related changes in the characteristics of the capacitor are compensated for, and a constant current is maintained through the diode load over a desired range of temperature. The driver is suitable for laser diodes and light emitting diodes.

Temperature compensated driver for pulsed diode light source

A Break Over Diode ('BOD') device is a gate-less two terminal high power semiconductor switch in which transitions from a blocking state to a conducting state are triggered by a dV/dt pulse to the anode. The BOD device can be thought of as two cross-coupled PNP and NPN transistors, and includes both anode and cathode shorts which reduce the gain of the NPN and PNP transistors by shunting some current away from their bases directly to their emitters, thereby improving blocking. Moreover, the anode and cathode shorts in conjunction with the device blocking junction form PN diodes which are distributed throughout the bulk of the material and function as anti-parallel diodes to the base-emitter junctions of the PNP and NPN transistors, which enables the BOD device to handle a larger current reversal for a longer period of time. The P base layer may be made thin to decrease the voltage fall time from full blocking to full conduction, and the cathode and anode shorts may be provided in a honeycomb pattern.

Silicon break over diode

To achieve both a fast risetime and a desired flat top current pulse, or to be able to independently specify a risetime and pulse width (energy), a supplemental or 'fast' voltage discharge stage (or multiple supplemental or 'fast' voltage discharge stages) having a faster and shorter voltage discharge characteristic and a higher starting voltage relative to the main or &#x201c;slow&#x201d; voltage discharge stage is used in parallel with the slow voltage discharge stage. The energy storage element of the slow voltage discharge stage has sufficient energy storage at an appropriate voltage level for maintaining the desired flat top current throughout the pulse duration, while the energy storage element of the fast voltage discharge stage has less energy storage capability but a higher starting voltage for achieving the desired fast current pulse risetime. Preferably, a single closing switch is used to couple all energy storage elements to the laser diode to pulse it, although respective separate switches may be used to couple the energy storage elements of the various voltage discharge stages to the laser diode.

Apparatus and method for driving a pulsed laser diode

Semiconductor switches, such as thyristors, may be light activated by introducing the light into the switch via a groove having a sloped surface to receive the triggering light. The use of a sloped surface increases the surface path length between points of different electrical potential in the groove and, therefore, reduces the likelihood of electrical breakdown on the groove wall. In one particular embodiment, a light-activated thyristor includes a semiconductor anode layer, an n-base layer, a p-base layer and a semiconductor cathode layer disposed parallel to a thyristor plane. A thyristor axis lies perpendicular to the thyristor plane. A groove having a light refracting side wall extends into the thyristor from the anode layer. A portion of the light refracting side wall is disposed non-parallel to the thyristor plane and to the thyristor axis, and extends in the n-drift layer.

Light-activated semiconductor switches

A laser-activated semiconductor switching device includes a semiconductor assembly including a multi-layer semiconductor structure having a first principal surface, and a laser assembly. The laser assembly includes at least one laser device and is directly connected to said first principal surface. The first principal surface includes a window area from which a metallization layer and an emitter layer of the semiconductor assembly are masked, such that laser light emitted from the laser assembly impinges through the window area directly onto a base layer of said semiconductor assembly to initiate current conduction by said switching device.

Laser-gated and pumped multi-layer semiconductor power switch with reduced forward losses

In an optically controlled thyristor having a four layer thyristor structure with respective first, second, third and fourth layers, the first and third layers have a first doping type, and the second and fourth layers have a second doping type different from the first doping type. A first shorting structure, formed from a semiconductor material of opposite doping from the first layer, is electrically coupled to the second layer by an electrically conducting, optically opaque layer. A first conductive layer connects between the first layer and the shorting structure and is adapted to transmit light into the first shorting structure. The first semiconductor layer of an optically controlled thyristor may have an aperture therethrough to permit light to enter the second layer from a first conductive layer side without propagating within the first layer. The semiconductor switch may be incorporated into a switching system having a light source controlled by a controller, and having a optical transmission channel coupled between the thyristor switch and the light source.

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Solana Beach, CA, United States of America

David M Giorgi