Nonlinearity-insensitive standard-fibre transmissionbased on optical-phaseconjugation in a semiconductor-laser amplifier

Abstract

Experimental results are presented confirming that optical-phase conjugation in a semiconductor-laser amplifier has the potential to compensate for the interplay of chromatic dispersion and nonlinear self-phase modulation, thereby enabling high-capacity high-power transmission over standard singlemode fibres

Approaching the Non-Linear Shannon Limit

“…For multi-level formats, these techniques may also be applied predicatively at the transmitter [61]. Full non-linearity compensation may be applied at the expense of complexity, either by optical phase conjugation [62,63], or via emulation of back propagation using look-up tables [64]. Assuming ideal compensation of all intra-channel effects other than noise, cross-phase modulation (XPM), which causes multiplicative noise, appears to be the principal source of impairments that fundamentally limits the information capacity of an optical communication system.…”

“…With the benefit of hindsight, we can say that each of the dispersion management schemes above follow the predictions of (7). In addition, these results partially benefited from a degree of non-linearity compensation, either through the use of guiding filters to combat intra-channel self-phase modulation [60,72], or via mid-span spectral inversion [62,70]. Coherent detection can greatly increase the limits to information capacity, and has attracted much interest recently for long haul transmission [33].…”

Long-Haul Fiber Transmission Using Optical Phase Conjugation

“…It should be noted that compensation using OPC is transparent as it compensates for both positive and negtive GVD and its effects do not depend on the optical modulation format [18]. The SPM compensation in fiber transmission has been experimentally confirmed by compensating for pulse-shape distortion due to large anomalous GVD and SPM [12,19]. Theoretical investigations indicate that OPC can be effectively applied to long-distance transmissions through both standard single-mode fiber (SMF) [18,20] and dispersion-shifted fiber (DSF) with normal dispersion [11,21,22].…”

Compensation of Nonlinear Fibre Impairments in Coherent Systems Employing Spectrally Efficient Modulation Formats

“…In the absence of noise, it can be proved that back-propagation method can fully compensate the linear and nonlinear fibre impairments to arbitrary precision, provided that sufficient steps are taken in each fibre span. Note that this method is similar to that of propagating the signal along an identical link after optical phase conjugation [10][11][12], but with added benefits that the impact of third order (and other odd ordered) dispersion may be accommodated. It is also noted that although precise calculation of the SSFM for back-propagation is still complicated, especially for multi-channel cases and higher sampling rate, various methods have been proposed to simplify the electronic signal processing [19][20][21][22][23].…”

“…The information rate in an optical transmission system is limited by the interplay between amplified spontaneous emission (ASE) noise, chromatic dispersion (CD), and Kerr fibre nonlinearity. The recent revival of coherent detection with the availability of high speed digital signal processing (DSP) technologies has enabled electronic mitigation of these effects [5,6], as an alternative to traditional techniques like dispersion management [7][8][9] and optical phase conjugation (OPC) [10][11][12]. In particular, electronic signal processing using back-propagation with inverse fibre parameters or time inversion has been applied to the compensation of intraand inter-channel nonlinearities [13][14][15][16][17][18].…”