Polarisation mode dispersion compensator using a mean square error technique

US7444082B2 · kind B2 · utility

Assignee

• ERICSSON AB · SE

Inventors

• Giulio Colavolpe · Parma, IT
• Enrico Forestieri · Parma, IT
• Giancarlo Prati · Pisa, IT

Key dates

• Filing date: Dec 3, 2002
• Grant date: Oct 28, 2008
• Expiry date: Apr 30, 2024

Classification

• Technology area (CPC G): Physics
• CPC primary: G02B6/4215
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A method for the adaptive adjustment of a PMD compensator in optical fiber communication systems comprises the steps of taking the signal at the compensator output and extracting the components y1(t) and y2(t) on the two orthogonal polarizations, computing the signal y(t)=[y1(t)]2+[y2(t)]2, sampling the signal y(t) at instants tk=kT with T=symbol interval to obtain samples y(tk), computing the mean square error e(k)=y(tk)−u(k) with u(k) equal to the symbol transmitted, and adjusting the parameters of the compensator to seek to minimize e(k). A PMD compensator in accordance with the method comprises an adjustment system which comprises in turn a photodetecor (17) which takes the components y1(t) and y2(t) on the two orthogonal polarizations from the signal at the compensator output, a sampler (19) which samples at instants tk=kT with T=symbol interval, the signal y(t)=[y1(t)]2+[y2(t)]2 at the output of the photodetector (17) to obtain samples y(tk), a circuit (18, 20) for computation of the mean square error e(k)=y(tk)−u(k) with u(k) equal to the symbol transmitted, and a regulator (15, 16) which regulates the parameters of the compensator to seek to minimize e(k).