Title: Coherent Octave-Spanning Light Generation in Optical Fibres: From Theory to Reality
Speaker: Dr Muhammad Imran Mustafa Abdul Khudus (Optoelectronics Research Centre, University of Southampton & Department of Physics, Faculty of Science, Universiti Malaya)
Time: Wednesday April 22nd 2026, 12:00 - 1:00 PM
Location: DKF, Department of Physics
Abstract:
Generating octave-spanning, narrow single linewidth, coherent broadband light in optical fibres is critical for advanced applications ranging from quantum metrology to precision material processing. However, current state-of-the-art solutions, such as Optical Parametric Oscillators (OPOs) pumped by supercontinuum sources, suffer from fundamental limitations including noisy generation, systemic complexity, and spectral instability. This research presents a paradigm shift to overcome these trade-offs by harnessing purely parametric Four-Wave Mixing (FWM) processes through engineered geometric and spatial dispersion control.The viability of this pure parametric approach is initially validated using Optical Microfibers (OMFs), where precise tuning of the fibre diameter enables targeted phase matching for cascaded frequency multiplication, yielding a 15 dB parametric gain. To scale this concept and achieve broader bandwidth, the research leverages intermodal FWM by exploiting the distinct propagation constants of varying spatial modes, such as the LP01 and LP11 modes. Experimental validations across multiple platforms showcase the power of this modal engineering: an elliptical core fibre (PMHN5) successfully demonstrated wavelength-selectable intermodal FWM via polarization control, while a few-mode fibre (PM2000) achieved a historic half-octave-spanning coherent generation across a 950–1250 nm bandwidth. Furthermore, the study explores the use of multicore fibres, utilizing their coupled supermodes to offer advanced phase-matching flexibility. By actively engineering dispersion rather than passively accepting material limitations, this approach provides a robust, highly coherent, and broadband solution to power next-generation photonic technologies.
About the Speaker:
Dr. Muhammad Imran Mustafa bin Abdul Khudus is a Senior Lecturer at the Department of Physics, Faculty of Science, Universiti Malaya. His research expertise encompasses fibre optics and waveguides physics, non-linear and quantum optics, and optoelectronics and lasers. He earned his PhD from Southampton University, UK, following his BSc (Hons) from Imperial College London and MSc with Distinction in Physics from University College London. Dr. Muhammad Imran has an h-index of 16 with 70 journal publications and over 680 citations, and he was recognized in 2023 as the academic staff with the highest external research grant at Universiti Malaya. Furthermore, he holds fellowships and memberships in several esteemed professional organizations, including the Institute of Physics, Optica (formerly the Optical Society of America), and Institut Fizik Malaysia.
