Interested students are encouraged to first discuss their interest with the Master Mentor for PhI,
Dr. Erwin Bente (Use this link for more details).
Internships are a highly effective way for students to gain work experience before graduation. We can arrange interviews for internships with our international industry partners for high-performing students in the Bachelor College program.
A typical internship will last for 3-4 month. Students have recently taken internships at Oclaro (UK), Fraunhofer Institute (DE) and NTT (JP).
If interested, you should send your CVs and course grades to the PhI secretariaat (secretariaat.phi@) tue.nl
Please find more information about an external project at:
Oclaro, EFFECT Photonics or SMART Photonics at your left hand side.
Graduation project at PhI Group/ASML: Simultaneous strain and temperature fibre-based sensing using a laser based readout system
Background: Strain and temperature sensing and their real time monitoring are important for many applications. In particular for ASML lithography machines the wafer stages accelerate really fast and suffer small deformations which degrade the exposure quality. Lasers and Fibre Bragg Gratings (FBGs) are the two enabling tools for building such a sensing systems. Integrated lasers in particular and photonic integration in general are interesting because they can significantly reduce size and cost. The Photonic Integration group (PHI) develops InP based photonic integration technology by which lasers, photodetectors, amplifiers, splitters and other components can be monolithically integrated on a chip. FBGs are optical resonators inside an optical fibre. These are used as the transducers for detecting the desired strain and temperature since these shift their optical resonance frequency which can be monitored using a laser system. However, a well-known problem is the distinction between strain and thermal effects (often referred to as cross-sensitivity) which diminishes the system’s performance and resolution.
Brief system description and objective: In this project in collaboration with ASML the sensing system will use an integrated continuous wave ring laser the wavelength of which is locked to a π-shifted FBG using the so called Pound-Drever-Hall (PDH) frequency stabilization technique. PDH is a technique which uses the reflection of phase modulated light off an optical resonator structure (the FBG) to detect any wavelength drifts of the laser away from the optical resonance. This signal is used in an electrical feedback circuit that controls the laser frequency such that it stays at the optical resonance. The laser is thus locked to the FBG resonance and by applying axial strain or changing the temperature the resonance shifts and the wavelength of the laser as well. This wavelength can be measured accurately and the shift allows one to calculate back the strain or temperature change. The main objective of the project is to evaluate how well the strain and temperature effects can be decoupled. Different strategies can be deployed to perform this decoupling but in this project we would like to investigate mainly the one based on birefringent FBGs and polarisation diversity.