Research Projects

The insatiable demand for data capacity-driven by 5G, AI, IoT, and cloud services, has pushed traditional single-core fiber (SCF) systems to their spectral limits. Spatial-division multiplexing (SDM) using multicore fibers (MCFs) offers a promising route to multiply capacity per fiber and OESCLU bands are needed to expand the usable optical spectrum beyond C+L, enabling higher total capacity and future-proofing fiber networks for ultra-high data demands. However, effective optical amplification remains a key barrier to deploying MCFs for long-haul communications. MCF-EDFA have been demonstrated in both core-pumped and cladding-pumped configurations. Raman amplification (RA), offers significant advantages over EDFAs, including broadband gain, ultra-low noise figure (NF), and flat amplification. This project aims develop a coupled and uncoupled MCF-RA simulation framework for a 4-core fiber and multiband system, which accommodates pump-signal interactions, polarization-dependent gain, core coupling, and inter-channel stimulated Raman scattering (ISRS)- based gain saturation. We will use global optimization methods: particle swarm optimization, genetic algorithms, gradient descent, and machine learning to design multi-pump configurations covering C+L and OESCLU bands, targeting flat gain (less than 1 dB ripple) and low effective NF across cores. The project will first extend existing SCF Raman amplifier models to coupled and uncoupled MCF by incorporating nonlinear coupled equations for pump and signal evolution, core-specific gain and loss parameters, and inter-core crosstalk. Optimization algorithms will be enhanced to optimize pump parameters for flat gain and low NF in a 4-core MCF-RA using forward, backward, or Bidirectional propagating pumps. The optimization will target DWDM systems with ITU-T grid spacing. For experimental validation, a 10 km 4-core MCF will be used for lab-scale amplification tests with backward-pumping and can also be emulated at longer lengths using the Recirculating loop. Transmission experiments will assess signal quality (GSNR, BER), gain flatness, and core-to-core performance variation using high-speed modulation formats up to 56 Gbaud symbol rates for the C+L bands and demonstrate greater than 1 Tbps coherent transmission performance. The project’s outcomes are expected to demonstrate the feasibility of scalable, low-noise, and broadband amplification in MCF systems, paving the way for next-generation high-capacity optical networks. This research aligns with the national goals of Digital India and future 6G connectivity by addressing the need for high-throughput optical infrastructure. It will contribute to India’s leadership in SDM-based communication technologies and will be disseminated through high-impact journals, conferences, and potential patents.