| PhD Seminar

Name of the Speaker: Mr. Sameer Ahmad Mir (EE19D418)
Guide: Prof. Deepa Venkitesh
Venue: ESB-234 (Malaviya Hall)
Date/Time: 31st January 2024 (Wednesday), 2:00 PM
Title: Capacity Scaling and Advanced Digital Signal Processing for Coherent Optical Systems

Abstract

Addressing the escalating demands for increased data capacity involves exploring solutions such as higher-order modulation formats and elevated symbol rates. The utilization of probabilistic constellation shaping (PCS) has also played a pivotal role in facilitating numerous groundbreaking achievements towards approaching capacity limits in recent optical fiber communication experiments. The most recent standard achieving 400 Gbps utilizes polarization-multiplexed 16QAM modulation at 56 Gbaud. However, as we push the boundaries by scaling either the modulation order or the symbol rates, the transmission system encounters challenge due to the impairments introduced by the system non idealities. These impairments pose a significant hurdle, showcasing the increasing difficulty in achieving and sustaining higher-order modulations. Therefore, we need advanced digital signal processing (DSP) algorithms to correct these impairments.

In the first part of talk, we present a novel carrier phase recovery algorithm tolerant to the transmitter IQ imbalance and Geometric parameter extraction-based algorithm for receiver IQ imbalance correction. In the second part of the talk, we talk about the probabilistic shaped signals (PCS). We also demonstrate the distortion less amplification of the PCS signals using semiconductor optical amplifiers and lastly, we show the DSP-free nonlinearity and dispersion mitigation of probabilistic shaped 16QAM signals using semiconductor optical amplifiers.