200 Gbps/λ PON Downstream C-Band Direct-Detection Links with ≥29 dB Power Budget

Abstract

In this paper we present the simulative analysis of a 200 Gbps per wavelength (λ) 8-level pulse amplitude modulation (PAM-8) downstream communication over up to 20 km single mode fiber (SMF) in C-band based on direct detection (DD) achieving at least a 29 dB link power budget in a PON environment. We use chromatic dispersion digital pre-compensation (CD-DPC) and a dual-arm in-phase and quadrature Mach–Zehnder modulator (IQ-MZM) at the optical line termination (OLT) side, while preserving DD in the optical network unit (ONU). Three receiver digital-signal-processing (DSP) options are analyzed and compared: square-root-like technique (SQRT) in combination with a feed forward equalizer (FFE) and a decision feedback equalizer (DFE), the Volterra nonlinear equalizer (VNLE), and the SQRT in combination with the VNLE. The SQRT can be applied in combination with the VNLE to decrease the receiver DSP complexity while maintaining the required system performance. We show that PAM-8 with CD-DPC and the SQRT in combination with the VNLE is a feasible solution for 200 Gbps per λ downstream C-band transmission for PON.

Advances in Optical Fiber Communications

“…The digital aid is introduced by Hadi and coworkers [8] and by Wang and coworkers [9]. In the former paper, digital predistortion is applied in the radio over fiber (RoF) scenario, using either conventional Volterra-based or deep learning methods to compensate for nonlinear impairments in optical front haul-based RoF systems.…”

“…Wang and coworkers [9] apply digital pre-compensation to the passive optical network scenario, showing a 29 dB power budget in a 200 Gbps communication system based on PAM-8 modulation over 20 km of standard single mode fiber. Pre-distortion at the transmitter is combined with three different digital signal processing techniques, with the receiver analyzing transmission performance as a function of overall digital complexity.…”

Simplified coherent receivers for passive optical networks

“…It is clear, that the traditional approach of intensity modulation / direct detection (IM/DD) coupled with non-return-tozero signalling is unlikely to meet the power budget requirements [5], [6] . Demonstration of IM/DD PON for 200 Gb/s line rate exist, however use PAM-4 or higher modulation [7], [8] format to increase spectral efficiency and are only able to meet power budget requirements using extensive DSP [9] and using Raman amplifiers [10] .…”