Polarization-Independent Phase-Sensitive Amplification

The capacity and reach of long-haul fiber optical communication systems is limited by in-line amplifier noise and fiber nonlinearities. Phase-sensitive amplifiers add 6 dB less noise than conventional phase-insensitive amplifiers, such as erbium-doped fiber amplifiers, and they can provide nonlinearity mitigation after each span. Realizing a long-haul transmission link with in-line phase-sensitive amplifiers providing simultaneous low-noise amplification and nonlinearity mitigation is challenging and to date no such transmission link has been demonstrated. Here, we demonstrate a multi-channel-compatible and modulation-format-independent long-haul transmission link with in-line phase-sensitive amplifiers. Compared to a link amplified by conventional erbium-doped fiber amplifiers, we demonstrate a reach improvement of 5.6 times at optimal launch powers with the phase-sensitively amplified link operating at a total accumulated nonlinear phase shift of 6.2 rad. The phase-sensitively amplified link transmits two data-carrying waves, thus occupying twice the bandwidth and propagating twice the total power compared to the phase-insensitively amplified link.

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“…For details on the requirements regarding the tracking and alignment of polarization in PSA links see ref. 27 …”

Section: Introductionmentioning

confidence: 99%

Long-haul optical transmission link using low-noise phase-sensitive amplifiers

et al. 2018

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“…What's more, the waves SOPs may not maintain along the fiber due to random birefringence or other slow polarization state drifts, which makes polarization independent gain unavailable. To solve this, a feedback loop can be introduced for polarization monitoring, or polarization maintaining fiber (PMF) is used instead [18].…”

Section: Simulation Configurationmentioning

confidence: 99%

QPSK Signal Regeneration Based on Vector Phase Sensitive Amplification With Low Pump Powers

Xing

Wang

2019

IEEE Access

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In this paper, an all-optical quadrature phase shift keying (QPSK) phase regeneration scheme using vector phase sensitive amplification (PSA) is proposed, analyzed, and simulated. Compared with the conventional scalar PSA scheme, the vector superposition of harmonics makes it easy to obtain high gain extinction ratio (GER) with low pump powers. A subsequent phase-preserving amplitude regenerating device is also introduced to achieve full-quadrature regeneration of signal without phase conjugation and frequency conversion. In addition to the theoretical analysis of the implementation principle, a series of simulation results' analysis, including comparison with traditional scheme and regeneration performance assessment, is also included. The results show that undesired harmonics are greatly reduced by nearly 40 dB, and high GERs are available independent of input power. What is more, various levels of phase and amplitude noise can be effectively compressed for 10-Gbd QPSK signal. The regeneration system also reduces the signal bit error rate and gets 2-dB receiver optical signal noise ratio (OSNR) improvements at 13-dB OSNR input, which has potential applications in enhancing transmission distance in the future optical communication network.INDEX TERMS All-optical signal regeneration, optical fiber communication, optical signal processing, optical polarization, phase sensitive amplification, quadrature phase shift keying.

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