Optical communications system and method of operation for performance recovery by post-transmission dispersion compensation

An improved fiber-optic Wavelength-Division Multiplexed system (WDM) including but not limited to standard unshifted fibers, comprising:

• (a) a WDM receiver coupled to the system for receiving an input signal with reduced transmission penalties;
• (b) means for changing the level of dispersion compensation in a first amplifier unit of the system;
• (c) means for changing the level of dispersion compensation in in-line amplifiers units of the system, where dispersion compensation in the in-line amplifiers is the same;
• and
• (d) means for providing post-transmission dispersion to the receiver input signal in a last amplifier unit before detection where the post compensation fiber length is different from fiber length of the dispersion compensation of the in-line amplifiers to compensate for distortion from non-linear effects and permit maximum signal power transmission in the range of 6 dBm to 12 dBm for optimum signal transmission.

An improved fiber optic Wavelength-Division-Multiplexed (WDM) system including a fiber transmission line having standard unshifted fibers and dispersion compensated fibers, comprising:

• (a) a transmitter coupled to one end of the fiber transmission line for transmitting in any modulating format;
• (b) a receiver coupled to the other end of the fiber transmission line for receiving the modulated signal with reduced transmission penalty;
• (c) in-line amplifier units installed in discrete intervals of the fiber transmission, each amplifier unit including dispersion compensated fibers, where dispersion compensation in the in-line amplifiers is the same;
• and
• (d) means for providing post-transmission dispersion to the modulated input signal in a last amplifier unit before detection where the post compensation is different in fiber length from dispersion compensation of the in-line amplifiers units to (a) compensate for distortion from non-linear effects and (b) permit maximum signal power transmission in the system, in the range of 6 dBm to 12 dBm.

Improved fiber-optic Wavelength-Division Multiplexed system (WDM) including but not limited to standard unshifted fibers, comprising:

• (a) in-line amplifier units installed in discrete intervals of the system, each amplifier unit including dispersion compensated fibers of the same length;
• where dispersion compensation in the in-line amplifiers is the same;
• and
• (b) means providing post-transmission dispersion compensation in a last amplifier unit before detection where the post compensation is different in terms of fiber length from the dispersion compensation of the in-line amplifier units to compensate for distortion from non-linear effects and permitting maximum signal power transmission in the system, in the range of 6 dBm to 12 dBm.