Hilight Semiconductor Limited

Derek John Hutchins

William Redman-White

Patrick Etienne Richard

George James Brocklehurst

Dominique Coue

Colin Whitfield

Christian Rookes

A system for controlling an optical intensity and modulation of an optical data transmitter which includes current driver circuitry configured to provide a drive current to a laser diode wherein said current comprises a fixed component and a modulated component, said modulated component having a magnitude related to an input data stream. The monitor circuitry contains a photodiode and a first transimpedance amplifier coupled to said photodiode, said monitor circuitry configured to provide an output signal related to an optical intensity of said laser diode. The system further includes replica monitor circuitry containing a replica capacitor with a replica capacitance and a second transimpedance amplifier configured to be substantially identical in construction to said first transimpedance amplifier, said second transimpedance amplifier coupled to said replica capacitor. The system further includes replica capacitance control circuitry configured to control said replica capacitance of said replica capacitor to match a capacitance associated with said photodiode.

Method for control of optical intensity and extinction ratio of laser modulation in an optical transmitter

A trans-impedance amplifier arrangement has an input configured to receive an output from a photo-detector, a current monitoring circuit configured in use to provide a current monitor signal dependent on a current through the photo-detector, and an output configured to output said current monitor signal to a control module, said output further configured to receive control information from said control module. A control module is configured to receive the current monitor signal and to provide the control information.

Trans-impedance amplifier arrangement and control module

Trans-impedance amplifier circuitry having an amplifier; a feedback resistor arranged between an output of the amplifier and an input of the amplifier; and at least one further resistor arranged physically parallel to the feedback resistor.

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Ringwood Hants, United Kingdom

Derek John Hutchins