Method of suppressing non-linearities in an optical communication system

Abstract

A method of optimizing a location of a blocking apparatus in an optical fiber system is disclosed. The method includes providing a first device and a second device; providing a fiber between the first device and the second device, the fiber having a predetermined length; determining the effective length of the fiber based on the predetermined length; and installing the blocking apparatus at the effective length of the fiber.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of U.S. Provisional Application No. 60 / 246,354, filed Nov. 7, 2000.FIELD OF THE INVENTION [0002] The present invention relates to optical fiber communication, including uni-directional cable TV systems, and uni- and bi-directional wavelength division multiplexing (WDM) systems. The invention also relates to a method and apparatus design for suppressing stimulated Brillouin and Rayleigh scattering in these systems. BACKGROUND OF THE INVENTION [0003] In long distance optical transmission systems, it is desirable to launch the highest optical power possible into the transmission fiber link. High power enables the signals to be transmitted over longer distances without the need for additional components such as regenerators, repeaters, and amplifiers, which increase the cost of communication systems. However, with the higher optical launch power, optical fibers exhibit non-linear effects such as stimulated...

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Problems solved by technology

High power enables the signals to be transmitted over longer distances without the need for additional components such as regenerators, repeaters, and amplifiers, which increase the cost of communication systems.

These phenomena can degrade the optical signals and increase bit error rates (BERs) for the data transmitted by the system.

Thus, SBS has been considered as setting a limit on the launched power level in optical fiber systems.

However, direct FM of an injection laser also results in substantial AM, called residual AM, which degrades the system performance, especially for analog transmission systems.

However, in optical transmission systems, this external PM technique typically degrades the dispersion characteristics of the signal due to an excessive increase in linewidth of the laser source.

But, increasing the SBS threshold further requires a high modulation index, which also requires very high RF drive power.

However, in optical transmission systems, this external PM technique typically results in degrading the dispersion characteristics of the propagating optical signal due to the excessive increase in linewidth of the laser source.

However, this approach is not practical because of the difficulty in manufacturing such fibers and the lack of use in already installed optical fiber systems.

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