Method for optical signal transmission with chromatic dispersion compensation through chirped optical fibre gratings, and optical communication system using the method
AssigneeAgilent Technologies, Inc.
InventorErnesto Ciaramella
Life of this patent
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Abstract
In a communication system with an optical fibre transmission line (3), a compensation of chromatic dispersion due to the fibre (3) is performed through at least one compensation module (4; 4A . . . 4N) based on chirped optical fibre gratings having a group delay characteristic τ(ω) which exhibits ripples around a nominally linear profile, as a function of the optical signal frequency. To minimise the effect of said ripples, the compensation is carried out in such a way that, for a given fibre length (3), the operating point is located in a limited slope region along the curve representative of system performance degradation owing to chromatic dispersion.
Claims10
A method of optical signal transmission comprising the steps of:
- introducing an optical signal into an optical fiber transmission line at a transmitter connected to an input to said optical fiber transmission line;
- transmitting said optical signal along said optical fiber transmission line to an output of said optical fiber transmission line;
- withdrawing said optical signal at said output by a receiver, whereby said transmitter, said optical fiber transmission line and said receiver form an optical transmission system;
- and
- compensating for chromatic dispersion caused by the optical fiber transmission line over a length thereof by:
- connecting at least one compensation module to said optical fiber transmission line that has a group delay characteristic τ(ω) fluctuating as a function of signal optical frequency (ω) around a nominally linear behavior,
- determining a degradation curve representing degradation of performance of the whole of said system due to optical dispersion as a function of length of the optical fiber transmission line,
- establishing for a given fiber length a region of limited slope of said degradation curve, and
- operating said at least one compensation module with an operating point limited to fluctuate around a value corresponding to a compensation carried out to maintain said nominally linear characteristic in said region of limited slope of said degradation curve.
An optical fiber communication system comprising a transmitter, amplifiers, an optical fiber transmission line and chromatic dispersion compensation modules, in which a transmitter sends optical signals over said optical fiber transmission line, said chromatic dispersion compensation modules including at least one compensation module having a group delay characteristic t(ω) which exhibits, as a signal optical frequency varies, fluctuations around a nominally linear behavior, said system comprising devices for determining a curve, for the whole of the system, representative of the system performance degradation owing to chromatic dispersion as a function of length of the line, said module having a slope of said group delay characteristic such that, for a given fiber length, the operating point on said curve representative of performance degradation lies in a region with limited slope of the curve.
Dependencies are inferred from the claim text.