Applied Materials, Inc.

Network Appliance, Inc.

Aerogage Corporation

James K Roberge

Robert J Ledoux

William Philip Nett

Stephen R Chinn

Wayne C Haase

Raymond Paul Boisseau

Philip A Lee

Boisseau Raymond Paul

Systems and methods for regulating optical power are described. A system for regulating optical power includes a laser driver circuit that receives an enable/disable signal and a data modulator input. The enable/disable signal regulates asynchronous mode operation. The system also includes a laser module including a laser diode emitter and a photodiode detector. The laser module is coupled to the laser driver circuit and receives a laser bias current from the laser driver circuit. The system also includes a switch coupled to the photodiode to receive a signal from the photodiode detector. The system also includes an automatic power control (APC) feedback circuit that receives a signal from the switch and provides a laser bias current feedback signal to the laser driver circuit to compensate for power output changes in the laser diode emitter over time.

System for regulating optical output power

A method and apparatus for generating an accurate, stable phase shift (b) in a sinusoidal signal employs fast analog multiplication to implement the trigonometric relationship sin(&ohgr;t&plus;b)&equals;sin(&ohgr;t)cos(b)&plus;cos(&ohgr;t) sin(b). Cos(&ohgr;t) is generated by accurately shifting a signal sin(&ohgr;t) through 90&deg; C. using a delay line, for example. Sin(b) and cos(b) are dc signals generated by digital to analog conversion, using a demanded phase shift (b) whose sine and cosine are obtained from look-up tables. A controller for controlling a phase shift in an rf cavity is also disclosed and operates on the basis of the same trigonometrical principle. The amplitude of the signals in the rf cavity is also controllable; fast analog multipliers are again employed to scale the signal amplitude to a nominal fixed value such as 1 volt.

Controller for a linear accelerator

A method and apparatus for generating an accurate, table phase shift (b) in a sinusoidal signal employs fast analog multiplication to implement the trigonometric relationship sin(&ohgr;t&plus;b)&equals;sin(&ohgr;t)cos(b)&plus;cos(&ohgr;t)sin(b). Cos (&ohgr;t) is generated by accurately shifting a signal sin(&ohgr;t) through 90&deg; using a delay line, for example. Sin(b) and cos(b) are dc signals generated by digital to analogue conversion, using a demanded phase shift (b) whose sine and cosine are obtained from look-up tables. A controller for controlling a phase shift in an rf cavity is also disclosed and operates on the basis of the same trigonometrical principle. The amplitude of the signals in the rf cavity is also controllable; fast analogue multipliers are again employed to scale the signal amplitude to a nominal fixed value such as 1 volt.

The measuring device of the invention uses a capacitor polarized by a continuous voltage and conditioned by a continuous charge amplifier, this charge amplifier having a high-band filter structure, preferably of the second order. The technology of the capacitor and the linking cable is coaxial. The tuning of the chain measurement is effected theoretically without needing standardization.

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Lincoln, MA, United States of America

James K Roberge