US 7,382,984 B2 · Electrical domain compensation of optical dispersion in an optical communications system

Abstract

Optical dispersion imposed on a communications signal conveyed through an optical communications system is compensated by modulating the communications signal in the electrical domain. A compensation function is determined that substantially mitigates the chromatic dispersion. The communications signal is then modulated in the electrical domain using the compensation function. Electrical domain compensation can be implemented in either the transmitter or the receiver end of the communications system. In preferred embodiments, compensation is implemented in the transmitter, using a look-up-table and digital-to-analog converter to generate an electrical predistorted signal. The electrical predistorted signal is then used to modulate an optical source to generate a corresponding predistorted optical signal for transmission through the optical communications system.

Claims31

Dependent claims

A method of compensating optical dispersion of a communications signal conveyed through an optical communications system, the method comprising steps of:

determining a compensation function that substantially mitigates the chromatic dispersion imparted to the communications signal by the optical communications system;
digitally processing an electrical input signal to be conveyed through the optical communications system, using the compensation function, to generate a predistorted electrical signal;
and
converting the predistorted electrical signal into a corresponding predistorted optical signal for transmission through the optical communications system;
wherein the step of determining a compensation function comprises steps of:
measuring a performance parameter related to the optical dispersion;
and
calculating respective values of one or more parameters of the compensation function that optimizes the measured performance parameter.

5 more elements

A dispersion compensator for compensating optical dispersion of a communications signal conveyed through an optical communications system, the dispersion compensator being implemented in a transmitter of the optical communications system, and comprising:

a compensation processor for digitally processing an electrical input signal to be conveyed through the optical communications system, using a predetermined compensation function, to generate a predistorted electrical signal for modulating an optical source of the transmitter;
such that modulation of the optical source generates a corresponding predistorted optical signal for transmission through the optical communications system;
wherein the compensation processor comprises any one of:
a Fast Fourier Transform (FFT) filter:
a Finite Impulse Response (FIR) filter;
and
an Infinite Impulse Response (IIR) filter:
and wherein the compensation processor comprises:
a look-up-table for calculating successive numerical values of the predistorted signal, based on the electrical input signal and the compensation function;
and
a digital-to-analog converter for converting each successive numerical value into a corresponding analog value of the predistorted signal.

8 more elements

Dependencies are inferred from the claim text.

Electrical domain compensation of optical dispersion in an optical communications system

Life of this patent

Electrical domain compensation of optical dispersion in an optical communications system

Life of this patent

Abstract

Claims31