Increase in reach of unrepeatered fiber transmission

1. A multiple-channel unrepeatered system employing nonlinearity compensation comprising:

(a) input data to be transmitted through the link;

(b) a nonlinearity pre-compensation block computing or estimating the waveform shapes to be imprinted onto the transmitted channels leading to the effective partial or complete cancellation of the nonlinear interaction in propagation;

(c) per wavelength-division multiplex channel computed waveforms;

(d) a bank of waveform generators used to imprint the channels' waveforms onto the transmitted optical field;

(e) a bank of corresponding optical transmitters;

(f) a wavelength division multiplexer joining the distinct transmitters and launching the generated channels into a single transmission link;

(g) a transmitter side optical amplification system;

(h) a transmission link devoid of inline lumped amplifiers;

(i) a receiver side optical amplification system;

(j) a wavelength division de-multiplexer used to separate the WDM channels and route them to their corresponding receivers;

(k) one or more receivers each of which being used to receive, process and detect information on one or more channels transmitted to the transmission link;

(l) a nonlinearity post-compensating block used for partial or complete cancellation of the nonlinear interaction in propagation by processing the received information bearing waveforms or their sub-sampled versions; and

(m)received data obtained after processing away nonlinear impairment,

wherein the channel information is shared among all wavelength carriers but is encoded by different symbolic or physical means.

2. The multiple-channel unrepeatered system of claim 1 wherein the received data undergoes additional processing by at least one technique selected from the group consisting of clock recovery, carrier phase recovery, frequency offset removal, equalization, and error control decoding.

3. The multiple-channel unrepeatered system of claim 1 wherein a single channel information is copied to multiple carriers occupying a set of or all transmitted wavelengths within the fiber transmission window.

4. The multiple-channel unrepeatered system of claim 1 wherein nonlinear distortion originating from intra-channel and inter-channel interaction is mitigated by a technique selected from the group consisting of: (a) inverting the NLSE that describes the interaction of all channels; (b) inverting the NLSE that describes the interaction of the channel subset; and (c) a predistortion technique that relies on knowledge of fiber physical characteristics and channel bit-history.

5. The multiple-channel unrepeatered system of claim 1 wherein a subset of the channel information is copied to multiple carriers occupying a set of transmitted wavelengths within the fiber transmission window.

6. The multiple-channel unrepeatered system of claim 5 wherein a selection of fractional data information to be distributed to a specific wavelength carrier is specifically performed in order to: (i) minimize nonlinear inter-channel interaction; and (ii) minimize the complexity of predistortion algorithm used to form the launch waveform or invert the NLSE at the receiver.

7. The multiple-channel unrepeatered system of claim 1 wherein the channel information is encoded by different symbolic means that include application of different forward-error correction codes (FEC) across the transmission window.

8. The multiple-channel unrepeatered system of claim 1 wherein the channel information is encoded by different physical means that include encoding distinct carriers by a wavelength-specific modulation format.

9. The multiple-channel unrepeatered system of claim 1 wherein the one or more receivers comprises a multiple-channel processing receiver.

10. The multiple-channel unrepeatered system of claim 9 wherein the multiple-channel processing receiver performs coherent summing to discriminate noise and increase the received SNR.

11. The multiple-channel unrepeatered system of claim 1 wherein the system employs higher-order Raman amplification designed to match increased signal launch power.

12. The multiple-channel unrepeatered system of claim 1 employing a parametric frequency comb.