Symmetric carrier assisted differential detection receiver with low-complexity signal-signal beating interference mitigation

Abstract

Low-cost, spectrally efficient self-coherent detection capable of optical field recovery is desired for inter-data center connections and metro networks. In this work, a simplified symmetric carrier assisted differential detection (S-CADD) receiver structure is proposed, which removes the single-ended photodiode branch and saves one ADC in standard asymmetric CADD (A-CADD) receivers. To compensate for the signal-signal beating (SSBI) impairment, a low-complexity iterative SSBI mitigation algorithm is put forward as well. The computational complexity is reduced by moving equalization, de-modulation and modulation out of each iteration. Based on single-carrier twin-single sideband (SSB) pulse- and quadrature-amplitude modulation (PAM and QAM) signals, the OSNR sensitivity with different carrier-to-signal power ratios (CSPRs) at back-to-back (BTB) scenario, the bit-error rates (BER) performance after 1000km fiber transmission, and the received optical power sensitivity at BTB are theoretically and numerically compared for both S-CADD and A-CADD receivers, respectively.

Highly Reliable Transmission System for Next-Generation Optical Access Network Based on Silicon Modulator With Maximum-Ratio Combined Receiver

“…Generally, after the square law detection of PD for the input signals, as shown in our system, the signal-to-signal beat interference (SSBI) occupies the same bandwidth as the signal from zero frequency. However, in our experiments, due to the wide guard band and high input carrier-to-signal power ratio (CSPR, ~12 dB), the influence of the SSBI on the system is marginal [32]- [34].…”

Analytical Study and Noise Mitigation for Complex-Valued Optical DSB Transmission With Carrier-Assisted Differential Detection Receiver

“…In Ref. [19], the theoretical derivation of the complexvalued optical DSB transmission with CADD receiver has been given, but the laser phase noise and fiber chromatic dispersion were neglected. It has been demonstrated that the EEPN originates from the interaction of laser phase noise and fiber chromatic dispersion [21][22][23][24][25][26].…”

“…And the Rx.DSP includes the SSBI cancellation, inverse transfer function, EDC, down-conversion, matched RRC filter, synchronization, equalization, PDA-BPS algorithm, symbol decision, and finally the SNR estimation module. The SSBI cancellation includes SSBI complex iterative elimination algorithm and SSBI simplified iterative elimination algorithm [19].…”

“…To further simplify the structure of the CADD receiver, a symmetric scheme without using the single-ended photodiode (SPD) branch was proposed and numerically studied in Ref. [19]. Considering that the electrical dispersion compensation (EDC) is lower in cost and easier to be implemented than the optical compensation scheme [18], the CADD system mainly adopt EDC.…”

“…Considering that the electrical dispersion compensation (EDC) is lower in cost and easier to be implemented than the optical compensation scheme [18], the CADD system mainly adopt EDC. To further reduce the costs, distributed feedback (DFB) lasers was adopted to replace high-cost external cavity lasers (ECL) without considering the effect of DFB laser's linewidth (LW) in the simulation to reduce the analysis complexity [19]. However, the influence of DFB lasers' wide linewidth, even reaching several MHz, a study of the influence of laser phase noise on the system performance is necessary.…”