PhD - Leuven | More than two weeks ago
Design discretized optical phased arrays for enabling large antenna arrays with high angular resolution in solid-state LiDAR systems
Emerging LiDAR systems focus on reducing their dependence on mechanical scanning devices. Over the past years, optical phased arrays (OPAs) based on photonic integrated circuits (PICs) have particularly gained visibility for solid-state beamforming applications. These devices can be densely packed on Si or SiN chips, taking advantage of existing advanced CMOS foundry manufacturing capabilities. In most common OPAs, the differential phase shift between two adjacent antennas that is required for beam steering is achieved through active devices (phase shifters). On the other hand, dispersive OPAs are fed with differential delay lines that deliver the required phase shift. Steering is now achieved by sweeping the wavelength of the laser source. This is an elegant beam steering approach that works well for small arrays (~100 emitters) but presents significant roadblocks when scaling up the optical arrays to thousands of emitters. The resulting chip area, optical loss, and phase errors make it therefore impractical to deploy large dispersive OPAs for long-range LiDAR systems.
To overcome the scaling problem, imec recently explored discretized OPAs [W. Bogaerts et al., IEEE Journal of Selected Topics in Quantum Electronics, vol. 27, p. 6100512, 2021]. The approach subdivides the large arrays into smaller manageable array blocks, that when combined produce a pixelated far-field pattern with the required angular resolution of the large array. The purpose of this PhD position is to expand on the initial discretized OPA designs by exploring additional degrees of freedom such as antenna power distribution, non-uniform/aperiodic arrays, sparse arrays, different delay line architectures, and multiplexing schemes for multi-port inputs. The required tasks involve design and modeling of novel OPA architectures, chip layout for device fabrication (in imec’s internal Si or SiN runs), and optical characterization.
Figure: Schematic of a discretized dispersive optical phased array, where each block consists of a snake-like OPA. It is also possible to use a Tree or AWG-like OPA in each block [W. Bogaerts et al., IEEE Journal of Selected Topics in Quantum Electronics, vol. 27, p. 6100512, 2021].
We are looking for a highly motivated recent graduate holding a master’s degree in photonics, applied physics, electrical engineering, or related field. The candidate must have an interest in design, modeling, and characterization of optical systems. Scripting and programming skills are a plus. The candidate is expected to report regularly on the progress and to be a team player, interacting closely with other team members. Good communication skills and excellent knowledge of English are also required, as you will work in an international, multidisciplinary and multicultural team spanning several imec departments.
Required background: Photonics, Nano-Engineering, Applied Physics, Electrical Engineering, or equivalent
Type of work: 10% literature study, 70% modeling and design, 20% characterization
Supervisor: Wim Bogaerts
Co-supervisor: Marcus Dahlem
Daily advisor: Roelof Jansen, Xavier Rottenberg
The reference code for this position is 2021-095. Mention this reference code on your application form.