Eindhoven University of Technology (TU/e) has the following PhD student vacancy for research on widely and continuously tunable laser diodes, in the research group Photonic Integration (PhI) of the department of Electrical Engineering.
Tunable lasers have a wide range of applications, most notably in spectroscopy and in optical fiber communications. Such lasers can be realized, for example, by using a diffraction grating for frequency-selective feedback into a gain medium. By rotating the grating, the wavelength of the laser can be changed. Such lasers tend to be rather expensive and are slow to change the wavelength, as the grating is mechanically rotated.
Laser diodes, or semiconductor lasers, offer a far more promising path towards low-cost and ubiquitous implementation of tunable lasers, and are extensively used in our optical networks, for example. So-called distributed-feedback lasers can be frequency-tuned over a few hundred Gigahertz, e.g., a few nanometer in the near-infrared. For wider tuning range, over about 10 nm or 1 THz, tricks like the Vernier-effect in sampled-gratings can be used . This tuning can be fast, by electro-optic means, but it is not continuous. Emerging applications of lasers in fiber-optic sensing, automotive lidar, terahertz imaging, and optical coherence tomography require widely and continuously tunable lasers, though.
In this project you will realize a novel type of fully integrated widely and continuously tunable laser. Our group has recently invented a new concept for this, which will be your starting point. This laser will initially be realized on a commercial photonic integration platform, such as offered by SMART Photonics in Eindhoven. You will numerically simulate, design and experimentally characterize this device, a so-called photonic integrated circuit (PIC) or optical chip. This project is part of a start-up grant, directly funded by the university, which means that there is a lot of scientific freedom to choose the next steps. One option is to explore this device further as a Fourier-domain mode-locked laser for the ultimate integrated frequency-swept source .
The project offers the opportunity to work on exciting new laser dynamics, implemented on a state-of-the-art technology platform, where you can try out different and novel designs. At the same time, this laser has a huge value for many commercial applications, so building a close collaboration with industry is anticipated. Coldren et al., "Tunable semiconductor lasers: A tutorial." Journal of Lightwave Technology 22, no. 1 (2004): 193, https://doi.org/10.1109/JLT.2003.822207
 Smit et al., "An introduction to InP-based generic integration technology." Semiconductor Science and Technology 29, no. 8 (2014): 083001, https://doi.org/10.1088/0268-1242/29/8/083001
 Huber et al., "Fourier Domain Mode Locking (FDML): A new laser operating regime and applications for optical coherence tomography." Optics express 14, no. 8 (2006): 3225-3237, https://doi.org/10.1364/OE.14.003225
The Institute for Photonic Integration (IPI) has five dynamic and ambitious research groups, which are closely cooperating: a systems group, a photonic integration technology group and three materials research groups. You will work in the Photonic Integration group (PhI) which has about 35 members, 20 of which are PhD students. The IPI (previously COBRA) is internationally leading on advanced InP-based Photonic Integrated Circuits technology. See, for example, http://iopscience.iop.org/article/10.1088/0268-1242/29/8/083001
for an overview of our technology.