In-Service Blind Transceiver IQ Imbalance and Skew Monitoring in Long-Haul Non-Dispersion Managed Coherent Optical Systems

Ju, Cheng; Liu, Na; Li, Changhong

doi:10.1109/access.2019.2947467

Cited by 24 publications

(4 citation statements)

References 15 publications

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“…From (3), we can appreciate that the presence of a FO has the effect of rapidly mixing the I and Q signal components in time. This phenomenon results in isolating the imbalance introduced by the transmitter and allows to develop strategies to separate their monitoring from the receiver-side imbalance [6], [10]- [12]. Furthermore, the FO separation results in a fundamental difference in the impact of Tx-side and Rx-side imbalance on system performance: while we can immediately compensate for Rx-side imbalance, Tx-side imbalance lies under the surface until carrier recovery is accomplished, affecting the performance of the whole DSP chain.…”

Section: B Receivermentioning

confidence: 99%

Characterization, Monitoring, and Mitigation of the I/Q Imbalance in Standard C-Band Transceivers in Multi-Band Systems

Rosa

Emmerich

Sena

et al. 2022

J. Lightwave Technol.

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Next-generation optical communication networks aim to vastly increase capacity by exploiting a larger optical transmission window covering the S-C-L-band. Simultaneously, the clear market trend is to maximize capacity per wavelength to reduce operational costs. This approach requires an increase in spectral efficiency, resulting in stringent requirements on the transceivers, which may not be satisfied in a multi-band (MB) scenario by current commercial components designed for operation in C-band. Transceiver specifications for MB operation can be relaxed through additional digital signal processing (DSP), at the cost of additional complexity, and by more resourceintensive calibration procedures. In this context, we experimentally characterize the wavelength-dependent frequency-resolved in-phase/quadrature (I/Q) imbalance of a standard C-band IQmodulator and coherent receiver operating in an S-C-L-band system utilizing receiver-side DSP. This operation allows us to understand the nature of the wavelength-dependency of I/Q imbalance in MB systems. In the considered scenario, we validate the effectiveness of a cost-effective strategy for transceiver impairments mitigation and monitoring based on standard wavelengthindependent calibration and reduced-complexity DSP.

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Section: B Receivermentioning

confidence: 99%

Characterization, Monitoring, and Mitigation of the I/Q Imbalance in Standard C-Band Transceivers in Multi-Band Systems

Rosa

Emmerich

Sena

et al. 2022

J. Lightwave Technol.

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“…Another candidate is the combination of a static filter and IQ-impairment-characteristic measurement techniques. Several techniques have been proposed for characterizing IQ impairments such as using multi-tone signals [12], phase retrieval [13], concatenated AEQs [14][15][16], Gram-Schmidt orthogonalization [17], and k-means clustering [18].…”

Section: Introductionmentioning

confidence: 99%

Digital Four-Dimensional Transceiver IQ Characterization

Kawai

Nakamura

Kobayashi

et al. 2023

J. Lightwave Technol.

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Signal impairments caused by the relative characteristic differences and crosstalk between electrical inphase (I) lanes and quadrature (Q) lanes are some of the main obstacles to the development of 100-Gbaud-class high-symbol-rate transceivers. To address such IQ impairments, we propose a method for enabling fully frequency-resolved four-dimensional (4D) characterization of IQ impairments even in the presence of arbitrary crosstalk across four IQ lanes of polarizationmultiplexed transceivers. We formulated a 4D signal-propagation model that takes into account inter-polarization IQ crosstalk and found how to separate the 4D IQ characteristics of the transmitter and receiver from the coefficients of a single-layer complex 8×2 multiple-input multiple-output adaptive equalizer on the basis of the model. We also introduce an application of the method for characterizing typical IQ impairments (e.g., IQ skew, IQ amplitude imbalance, phase deviation) from the filter coefficients. We numerically and experimentally tested our method with 96-Gbaud 16QAM signals and demonstrated its feasibility.

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“…However, GSOP requires data buffering, leading to latency in processing and challenges for parallel implementation [13]. Authors in [30] have modelled and derived the interaction between transceiver imbalance and fiber link, and found the transceiver imbalance values for in-service calibration. However, the complexity of the model is very high, and the proposed scheme was not investigated experimentally.…”

Section: Introductionmentioning

confidence: 99%

Widely Linear Filtering for Multiimpairment Compensation in Dispersion Managed mQAM Modulated Optical Systems

et al. 2022

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We propose a blind joint equalization algorithm for M-QAM signals based on a widely linear filtering approach. The proposed scheme jointly compensates for receiver IQ imbalance, receiver IQ skew, polarization mixing, carrier recovery, followed by transmitter IQ imbalance and skew. We first investigate the proposed scheme's tolerance to each of these impairments through numerical simulations for 32 GBd PM-16QAM and PM-64QAM signals and compare its performance with the conventional digital processing algorithms with and without IQ imbalance compensation. The proposed joint transceiver equalizer outperforms the conventional algorithms with a Q 2 improvement of greater than 1 dB, and with improved tolerance to IQ imbalance. Further, with the proposed algorithm, we experimentally demonstrate the improvement in Q 2 value with respect to conventional DSP for both PM-16QAM and PM-64QAM signals. We also show that the MSE convergence of the proposed joint equalizer is much faster than conventional DSP algorithms.

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In-Service Blind Transceiver IQ Imbalance and Skew Monitoring in Long-Haul Non-Dispersion Managed Coherent Optical Systems

Cited by 24 publications

References 15 publications

Characterization, Monitoring, and Mitigation of the I/Q Imbalance in Standard C-Band Transceivers in Multi-Band Systems

Characterization, Monitoring, and Mitigation of the I/Q Imbalance in Standard C-Band Transceivers in Multi-Band Systems

Digital Four-Dimensional Transceiver IQ Characterization

Widely Linear Filtering for Multiimpairment Compensation in Dispersion Managed mQAM Modulated Optical Systems

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