Mid-infrared Vernier racetrack resonator tunable filter implemented on a germanium on SOI waveguide platform [Invited]

Abstract

Currently, most widely tunable lasers rely on an external diffraction grating to tune the laser wavelength. In this paper we present the realization of a chip-scale Vernier tunable racetrack resonator filter on the Ge-on-SOI waveguide platform that allows for wide tuning (108 nm free spectral range) in the 5 µm wavelength range without any moving parts. The fabricated racetrack resonators have a loaded Q-factor of 20000, resulting in a side-peak suppression of more than 20 dB, which is more than sufficient for wavelength selection in an external cavity laser.

Ultrafast polarization switching in ferroelectrics

“…The quantities γ s and t 0 are the integration constants that are defined by sewing expressions (51) and (52) with Eqs. (49).…”

Tunable Germanium-on-Insulator Band-Stop Optical Filter Using Thermo-Optic Effect

“…As the thermal conductivity of silicon (Si) is relatively high at 130 Wm −1 K −1 [16], the underlying Si layer effectively acts as a heat sink, hence preventing any efficient heating on the Ge photonic patterns. In order to prevent such heat loss, undercutting the Si for GOS or silicon dioxide (SiO 2 ) for Ge-on-SOI is utilized which vastly complicates the fabrication process [17], [18].…”

Mid-infrared GaAs/AlGaAs micro-ring resonators characterized via thermal tuning

“…24) and germanium-based strategies have been presented for operation in the long wave mid infrared. 25,26 As an alternative, the III-V semiconductor material gallium arsenide (GaAs) may be deposited onto an optical buffer layer made from aluminium gallium arsenide (AlGaAs) thus providing a possibly wide transparent window in the MIR (i.e., 0.9-25 mm), as pioneered by Mizaikoff and collaborators. 27,28 GaAs/AlGaAs systems therefore can be utilized throughout the whole near-, mid-and far-infrared with the possibility to monolithically integrate the waveguides with sources, especially quantum cascade lasers (QCLs), and detector schemes.…”