Equalization Enhanced Phase Noise in Coherent Optical Systems with Digital Pre- and Post-Processing

Kakkar, Aditya; Navarro, Jaime Rodrigo; Schatz, Richard; Pang, Xiaodan; Ozoliņš, Oskars; Louchet, Hadrien; Jacobsen, Gunnar; Popov, Sergei

doi:10.3390/photonics3020012

Cited by 5 publications

(5 citation statements)

References 27 publications

(61 reference statements)

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“…The LO laser on the other hand causes, apart from the phase noise, also timing impairment and different design criteria apply for different FN regimes. As discussed in our previous work, there exist more than one configuration for performing all-digital signal processing 20 . The order of the digital signal processing decides whether the Tx laser, LO laser or both causes the presented phenomenon.…”

Section: Discussionmentioning

confidence: 99%

“…However, many questions still remain unanswered, particularly the consideration that lasers in general have non-white FN spectrum. The laser FN spectrum is generally non-white due to the presence of 1/f noise and, in the case of semiconductor lasers, also carrier induced noise 20 , 21 . Therefore, a more in-depth analysis considering a laser with a general non-white FN spectrum compared to the previously provided statistical analysis, is needed.…”

Section: Introductionmentioning

confidence: 99%

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Laser Frequency Noise in Coherent Optical Systems: Spectral Regimes and Impairments

Kakkar

Navarro

Schatz

et al. 2017

Sci Rep

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Coherent communication networks are based on the ability to use multiple dimensions of the lightwave together with electrical domain compensation of transmission impairments. Electrical-domain dispersion compensation (EDC) provides many advantages such as network flexibility and enhanced fiber nonlinearity tolerance, but makes the system more susceptible to laser frequency noise (FN), e.g. to the local oscillator FN in systems with post-reception EDC. Although this problem has been extensively studied, statistically, for links assuming lasers with white-FN, many questions remain unanswered. Particularly, the influence of a realistic non-white FN-spectrum due to e.g., the presence of 1/f-flicker and carrier induced noise remains elusive and a statistical analysis becomes insufficient. Here we provide an experimentally validated theory for coherent optical links with lasers having general non-white FN-spectrum and EDC. The fundamental reason of the increased susceptibility is shown to be FN-induced symbol displacement that causes timing jitter and/or inter/intra symbol interference. We establish that different regimes of the laser FN-spectrum cause a different set of impairments. The influence of the impairments due to some regimes can be reduced by optimizing the corresponding mitigation algorithms, while other regimes cause irretrievable impairments. Theoretical boundaries of these regimes and corresponding criteria applicable to system/laser design are provided.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Laser Frequency Noise in Coherent Optical Systems: Spectral Regimes and Impairments

Kakkar

Navarro

Schatz

et al. 2017

Sci Rep

Self Cite

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“…K. Zhong et.al discusses the application of signal processing at receiver end for dispersion compensation in short Optical communications [7]. Kakkar, A et.al discusses the application of digital signal processing at both receiver end and at transmitter side for dispersion compensation [8]. Dispersion is also compensated in electronics means by pre-processing the signal and compensating it for dispersion at the transmitter end by substituting the signal using 2n bit look up table [9].…”

Section: Introductionmentioning

confidence: 99%

Performance Analysis of Dispersion Compensation Schemes with Delay Line Filter

2021

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Optical communication is an effective system to achieve the high-speed data transmission for long distance. The main factor that affects the optical communication is dispersion. Dispersion leads to reduction of the system performance and Q-factor. Dispersion can be compensated using various techniques. Major techniques are compensation using Dispersion Compensating Fiber (DCF), Fiber grating technique, and Delay Line Filter (DLF). Analysis has been performed on the Bit Error Rate (BER) and Quality Factor (Q-Factor) of various schemes based on Eye Opening Penalty (EOP) with BER analyzer for dispersion compensation. It has been concluded that Impulse Invariant Response (IIR) based DLF at average results in 50% of better compensation when compared Fiber Bragg Grating and DCF based compensation techniques. The power of the received signal when transmitted at 0 dBm for 120 kms is-12.325 dBm which is the optimum power in which the signal can be received without distortion.

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“…However, the chromatic dispersion (CD), the polarization mode dispersion (PMD), the laser phase noise (PN), as well as Kerr fiber nonlinearities (NLs) severely degrade the performance of optical communication systems, leading to constraints on achievable information rates (AIRs), a measure of achievable capacity of communication systems [6,7]. Advancements in powerful digital signal processing (DSP) enhanced the reaches of optical communication systems and achieved the compensation of transmission impairments via the use of electronic dispersion compensation (EDC), digital backpropagation (DBP), and carrier phase estimation (CPE) [8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Impact of Equalization-Enhanced Phase Noise on Digital Nonlinearity Compensation in High-Capacity Optical Communication Systems

Ding

Jin

et al. 2020

Sensors

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Equalization-enhanced phase noise (EEPN) can severely degrade the performance of long-haul optical fiber transmission systems. In this paper, the impact of EEPN in Nyquist-spaced dual-polarization quadrature phase shift keying (DP-QPSK), dual-polarization 16-ary quadrature amplitude modulation (DP-16QAM), and DP-64QAM optical transmission systems is investigated considering the use of electrical dispersion compensation (EDC) and multi-channel digital backpropagation (MC-DBP). Our results demonstrate that full-field DBP (FF-DBP) is more susceptible to EEPN compared to single-channel and partial-bandwidth DBP. EEPN-induced distortions become more significant with the increase of the local oscillator (LO) laser linewidth, and this results in degradations in bit-error-rates (BERs), achievable information rates (AIRs), and AIR-distance products in optical communication systems. Transmission systems using higher-order modulation formats can enhance information rates and spectral efficiencies, but will be more seriously degraded by EEPN. It is found that degradations on AIRs, for the investigated FF-DBP schemes, in the DP-QPSK, the DP-16QAM, and the DP-64QAM systems are 0.07 Tbit/s, 0.11 Tbit/s, and 0.57 Tbit/s, respectively, due to the EEPN with an LO laser linewidth of 1 MHz. It is also seen that the selection of a higher-quality LO laser can significantly reduce the bandwidth requirement and the computational complexity in the MC-DBP.

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Equalization Enhanced Phase Noise in Coherent Optical Systems with Digital Pre- and Post-Processing

Cited by 5 publications

References 27 publications

Laser Frequency Noise in Coherent Optical Systems: Spectral Regimes and Impairments

Laser Frequency Noise in Coherent Optical Systems: Spectral Regimes and Impairments

Performance Analysis of Dispersion Compensation Schemes with Delay Line Filter

Impact of Equalization-Enhanced Phase Noise on Digital Nonlinearity Compensation in High-Capacity Optical Communication Systems

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