White light generation with ultra-short pulses in waveguides

Chair: Laser physics and nonlinear optics (LPNO)
White light generation with ultra-short in silicon nitride waveguides
When ultra-short laser pulses with extreme high peak intensities propagate through a medium it is
possible that the monochromatic laser light evolves into white light due to nonlinear interactions with
the material. These extremely broadened spectra (see Fig. 1) are called supercontinua.
To generate efficiently a supercontinuum the laser light has to propagate through a waveguide,
where it is confined in space as well as in frequency. In this project the waveguide has a higher index
core made of Si3N4 which is surrounded by lower index material like SiO2 and air.
Figure 1: a) TE mode of a silicon nitride core on a silicon dioxide substrate surrounded by air at a laser
wavelength of 1300 nm. b) Numerical simulation of the frequency broadening for a pump pulse of 500
fs in duration and having a wavelength of 1500 nm versus propagation length in a silicon nitride
The goal of this project is to couple ultra-short laser pulses into silicon nitride waveguides with different
cross sections and observe the spectral broadening of the laser pulses. The results can be compared
to numerical simulations and lead to a better understanding of the nonlinear interactions in silicon
nitride waveguides.
This project allows to gain insight into the research field of photonics and nonlinear optics. In addition,
there is also the opportunity to work on numerical simulations of nonlinear processes.
Tutor: Marco Garcia-Porcel
Teacher: dr. Klaus Boller
ME 231A
ME 124
Project room