Research

I work across photonic device design and experimental characterization, from modelling how light propagates through a device to building the setups needed to measure its performance.

Design

How do we design photonic devices for specific performance goals?

Photonic devices augment technologies such as high-speed communication, where component performance dictates system capabilities. I am interested in designing active and passive photonic components to meet demanding requirements for bandwidth, loss, and signal integrity.

My doctoral research focused on photonic crystal devices for terahertz communication and sensing, exploring how photonic crystal structures can guide electromagnetic modes with low loss even across sharp corners. This work included designing waveguides, waveguide-cavity systems, and interferometers. Two of my key contributions in this field are the implementation of a terahertz Mach-Zehnder interferometer and a broadband waveguide achieving aggregate data rates exceeding 400 Gbps.

I use electromagnetic modelling and simulation to guide the design and optimization of photonic devices. My broader interests include integrated photonics, high-speed electro-optic devices, and optical interconnects.

design light design dark Chips I have designed and characterized

Representative publications

  1. Monolithic Terahertz Topological Mach-Zehnder Interferometer N. Navaratna, Y. J. Tan, W. Wang, et al. Advanced Materials, 2025.
  2. Slow light topological photonics with counter-propagating waves and its active control on a chip A. Kumar, Y. J. Tan, N. Navaratna, et al. Nature Communications, 2024.
  3. Ultralow-Dispersion Silicon THz Photonic Crystal Interconnects for Multichannel Datalinks N. Navaratna, T. C. Tan, P.Szriftgiser, et al. Advanced Materials, 2026.

Test

How do we validate photonic device performance in the lab?

I enjoy building experiments that test device designs against their intended performance targets. I have built and operated experimental setups for photonic device characterization, from calibrated S-parameter measurements using vector network analysers to photonics-aided communication testbeds. These setups have enabled me to measure device responses and evaluate data transmission using metrics such as error vector magnitude (EVM) and bit error rate (BER).

I work across the measurement chain, from generating and modulating optical signals to interfacing with high-frequency devices and analysing the recovered data.

Block diagram of the photonics-aided communication testbed: two lasers, an IQ modulator driven by an arbitrary waveform generator, an optical amplifier and attenuator, a photodiode feeding the device under test, a mixer with a local oscillator, an amplifier and a real-time oscilloscope Communication testbed used to send data through the chip.

Both threads come together in my Ph.D. thesis (NTU Singapore). The full publication list is on Google Scholar.