Cisco Technology, Inc.

USA as Represented by Secretary of the Navy

Stephen A Pappert

Chen-Kuo Sun

Richard J Orazi

Donald J Albares

Matthew N McLandrich

Techniques and system implementations for fiber optic transmission systems for suppressing fiber induced distortions and modulation-induced distortions as well as increasing the link power and RF gain.

High power, optically-linearized microwave fiber optic link with suppression of fiber induced distortion

Techniques and systems for reducing nonlinear distortions in an output optical beam from an optical transmitter by using both electrical pre-distortion compensation and optical compensation.

Hybrid optical and electrical fiber optic link linearizer

A dynamic range extender for optical transmitters comprises a bipolar distortion compensator for increasing drive signal gain as the absolute level of an input signal increases beyond a selected input voltage threshold, a signal coupler for dividing the input signal into complementary signals, a unipolar distortion compensator for increasing drive signal gain of each complementary signal beyond a selected forward current threshold, a signal clipper for pre-clipping each complementary signal below a selected clipping threshold, and complementary driver outputs to drive each of a pair of laser diodes in a complementary push-pull arrangement. The pre-clipping prevents the laser diodes from being driven below their threshold current level, and the distortion compensation suppresses second and third order harmonic distortion when the complementary signals generated by the laser diodes are combined by differential photodiodes.

Dynamic range extended for optical transmitters

An optical system and method include a short coherence length edge, emitt LED, a fiber optic coupler probe, and a Michelson interferometer to measure the parameter of thickness of optical devices, such as thin silicon substrate samples and to characterize other parameters of optical waveguide devices such as absolute attenuation, effective refractive index, and changes in these parameters with the application of a modulation voltage or an external disturbance. The measurable thickness range from a few to hundreds of microns with a thickness precision exceeding 0.1 micron for a 10 micron sample. In situ localized measurements of samples in an etching chamber are obtainable to control processing and provide for thickness uniformity. Attenuation measurements for optical waveguides compare the values of interferogram maxima at the values of the reference arm path length to changes corresponding to one and two times the optical path length of the sample. Effective refractive index is determined by counting the number of fringes in the recorded interferogram between successive maxima. Changes in these parameters due to an external disturbance are measured by comparing the interferograms before and after. The sample stays in the system during all measurements which can also indicate the degree of coupling or interaction between simultaneous refractive index and absorption changes.

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San Diego, CA, United States of America

Stephen A Pappert