Electronic post-compensation of optical transmission impairments using digital backward propagation
View Patent ↗Systems and method of compensating for transmission impairment are disclosed. One such method comprises: receiving an optical signal which has been distorted in the physical domain by an optical transmission channel; and propagating the distorted optical signal backward in the electronic domain in a corresponding virtual optical transmission channel.
1. A method of compensating for transmission impairment, the method comprising:
receiving an optical signal which has been distorted in a physical domain by an optical transmission channel; and
propagating the distorted optical signal backward in an electronic domain in a corresponding virtual optical transmission channel.
2. The method of claim 1 , wherein the optical signal is a wavelength-division multiplexed signal.
3. The method of claim 1 , wherein the optical signal is a polarization-division multiplexed signal.
4. The method of claim 1 , wherein the optical transmission channel includes an optical fiber and an optical amplifier, and the virtual optical transmission channel includes a virtual optical fiber, the method further comprising:
modeling the virtual optical fiber according to a non-linear Schrödinger equation (NLSE) using dispersion, loss and nonlinearity parameters which are opposite in value to a plurality of corresponding parameters for the optical fiber, to account for dispersion, intra-channel, and at least some inter-channel impairments.
5. The method of claim 4 , wherein the virtual optical transmission channel includes a virtual attenuator, the method further comprising:
modeling the virtual attenuator with an attenuation parameter that balances the gain of the corresponding optical amplifier.
6. The method of claim 4 , wherein the NLSE is a total NLSE (T-NLSE).
7. The method of claim 4 , wherein the NLSE is a coupled NLSE (C-NLSE).
8. The method of claim 4 , further comprising:
solving the NLSE using a split-step Fourier method.
9. The method of claim 4 , further comprising:
solving the NLSE using a split-step infinite impulse response method.
10. The method of claim 4 , wherein the optical system is an imaging system, wherein the optical system further comprises a transmitter, receiver and transmission channel, and the received optical signal contains a spatially varying image.
11. The method of claim 10 , where the spatial image is static.
12. The method of claim 10 , where the spatial image varies in time.
13. A receiver comprising:
memory containing instructions stored thereon;
a processor configured by the instructions;
an optical detector configured to receive an optical signal which has been distorted in a physical domain by an optical transmission channel and further configured to provide a corresponding distorted electrical signal to the processor,
wherein the processor is configured by the instructions to:
propagate the distorted electrical signal backward in an electronic domain in a corresponding virtual optical transmission channel.
14. The receiver of claim 13 , wherein the received optical signal is a wavelength-division multiplexed signal.
15. The receiver of claim 13 , wherein the received optical signal is a polarization-division multiplexed signal.
16. The receiver of claim 13 , wherein the optical transmission channel includes an optical fiber and an optical amplifier, and the virtual optical transmission channel includes a virtual optical fiber and a virtual attenuator, and wherein the processor is further configured to:
model the virtual optical fiber according to a non-linear Schrödinger equation (NLSE) using dispersion, loss and nonlinearity parameters which are opposite in value to the corresponding optical fiber parameters, to account for dispersion, intra-channel, and at least some inter-channel impairments; and
model the virtual attenuator with an attenuation parameter that balances the gain of the corresponding optical amplifier.
17. The receiver of claim 13 , wherein the NLSE is a total NLSE (T-NLSE).
18. The receiver of claim 13 , wherein the NLSE is a coupled NLSE (C-NLSE).
19. The receiver of claim 13 , wherein the processor is further configured to:
solve the NLSE using a split-step finite impulse response method.
20. The receiver of claim 13 , wherein the processor is further configured to:
solve the NLSE using a split-step finite impulse response method wherein each step is performed in parallel.
21. The receiver of claim 17 , wherein the processor is further configured to:
solve the NLSE using split step Fourier-transform method.
22. The receiver of claim 17 , where the block processing is implemented using the overlap-and-add method.
23. The receiver of claim 17 , where the block processing is implemented using the overlap-and-save method.
24. The receiver of claim 17 , wherein the processor is further configured to:
solve the NLSE using a split-step finite impulse response method.
25. The receiver of claim 17 , wherein the processor is further configured to:
solve the NLSE using a split-step finite impulse response method wherein each step is performed in parallel.