/Actively Stabilized Low-noise and Isolator-free III-V-on-Si Lasers for DWDM Optical Interconnects

Actively Stabilized Low-noise and Isolator-free III-V-on-Si Lasers for DWDM Optical Interconnects

PhD - Leuven | More than two weeks ago

Energy-efficient and high-bandwidth optical transceivers are critical for emerging infrastructures such as HPC supercomputer and datacenters. DWDM light source integrated with silicon is one of the essential building blocks toward the high-performance optical transceivers.

On-chip III-V-on-Si lasers with low-noise and narrow linewidth have recently been demonstrated, leveraging the integration of III-V materials in a low loss Si/SiN platform. Such lasers are in high demand for a wide variety of applications such as optical fiber communications, optical sensing, microwave, and quantum photonics thanks to their extremely low-noise and high coherence. A high-performance laser is usually vulnerable to external reflections and required an optical isolator (OI) to shield it from unwanted optical feedback. However, the OI cannot be integrated with the laser in a photonic integrated circuit (PIC), leaving the on-chip laser vulnerable to parasitic optical feedback coming from various photonic devices on the PIC, while increasing costs and complexity when adding the OI to the package. 


The goal of the proposed PhD is to investigate actively stabilized isolator-free low-noise narrow linewidth multi-wavelength III-V-on-Si lasers using an opto-electronic feedback loop. The student will be able to use imec’s Si/SiN 200-300 mm photonic platforms for the III-V-on-Si integrations. The PhD student will also design laser diodes naturally less sensitive to external reflections such as quantum dot lasers and tunable lasers toward DWDM requirement. This work is expected to result in the demonstration of multi-wavelength III-V-on-Si lasers bypassing the need of an OI while maintaining low-noise and narrow linewidth performance. 

What you will do 

Over the PhD, your work will cover all aspects of research, from optical simulations and laser design, PIC fabrication of heterogeneously integrated lasers in a clean room, to electro-optical characterization of fabricated devices. Focuses will be on the characterization of fabricated devices and on the development and demonstration of an opto-electronic feedback system to maintain laser with low-noise and narrow linewidth under varying external optical reflections. This will involve some system integration and electronics work. You will learn about the design of advanced InP-on-Si lasers, their fabrication, and their characterization. You will also gain experience in advanced characterization techniques for measuring laser frequency and intensity noises, as well as assembling laser modules that include electronic components on printed circuit boards. This PhD will encompass everything from design to assembly of laser modules for real applications. 

Required background: MSc degree in Applied Physics, Electrical Engineering, or Optical Engineering

Type of work: 10% literature study, 35% modeling/simulation, 20% fabrication, 35% characterization

Supervisor: Geert Morthier

Daily advisor: Hsiao-Lun Wang

The reference code for this position is 2024-010. Mention this reference code on your application form.

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