Silicon Photonics

At the Laboratory of Optics of Quantum Materials (LOQM), IIT Bombay, we develop chip-scale silicon photonic devices that form the foundation for next-generation integrated photonic circuits. Our research focuses on silicon nitride microresonators, bus waveguides, and grating couplers, with detailed characterization using tunable lasers and precision spectroscopy.

Our work enables applications in sensing, spectroscopy, and chip-scale photonic experiments, and lays the groundwork for future photonic module integration.

Key Research Areas

1. Silicon Nitride Microresonators

We fabricate high-Q microresonators on silicon nitride platforms. These devices support nonlinear optics, frequency comb generation, and filtering applications.

2. Bus Waveguides

LOQM designs and characterizes waveguides to efficiently couple light to microresonators and other photonic elements. Performance metrics such as insertion loss and coupling efficiency are carefully measured.

3. Grating Couplers

We develop fiber-to-chip coupling solutions using grating couplers, enabling efficient light injection into integrated photonic circuits.

4. Device Characterization

Characterization informs design optimization for low-loss and high-performance devices.

Using external cavity diode lasers (ECDL), we measure transmission spectra, resonance wavelengths, and Q-factors.

Selected Projects & Achievements

  • Prototype chip-scale silicon photonic resonators integrated with monolithic as well as 2D material based emitters.
  • Demonstration of indigenous low loss microresonators, bus waveguides, grating couplers and tapers for sensing applications.
  • Publications and preprints on chip-scale device fabrication and characterization, contributing to India’s integrated photonics research ecosystem.

Facilities & Techniques

  • Nanofabrication: Lithography, etching, and deposition for Si₃N₄ photonic devices.
  • Optical Characterization: Transmission spectroscopy using ECDL, wavelength sweeps, and coupling efficiency measurements.
  • Design Tools: Simulation of waveguides, microresonators, and grating couplers using photonic design software.

Future Directions

While our current focus is on device-level research, LOQM is building capabilities toward fully integrated photonic modules, including potential integration with optical transmitters and receivers (TOSA/ROSA), photonic circuits for sensing, and chip-scale platforms for quantum and classical photonics experiments.

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