Compensation of Optical Signal Error Through Digital Post-Processing

Abstract

Researchers at the University of Central Florida have developed a digital signal processing (DSP) method of post-compensation for impairments. Optical signal processing hinges on the system's ability to compensate for the error accumulated by optical pulses as they travel through air or a waveguide apparatus, such as a fiber optic cable. The optical signal unavoidably succumbs to a variety of impairments, including absorption, dispersion, nonlinearities, and amplifier noise. In the past, optical techniques have attempted to physically compensate for these errors but have led to only marginal success as physical systems vary greatly in detail. Therefore, the trend has shifted toward electronic error correction.

Technical Details

First applied to artificial neural networks, backward propagation of errors (back propagation) is a method for teaching a data correcting element the response of a nonlinear system when it is not possible to use standard impulse response methods. With the UCF technology, this method is applied to an algorithm that learns the amount of each optical error present in the system using a known teaching signal. A received and impaired signal is sent backward through a virtual version of the system to gauge error weights. The system then uses that knowledge to compensate for normal operational signal recognition.

Benefit

Market Application