Conference paper
Wavelength tunable MEMS VCSELs for OCT imaging
Department of Photonics Engineering, Technical University of Denmark1
Nanophotonic Devices, Department of Photonics Engineering, Technical University of Denmark2
Quantum and Laser Photonics, Department of Photonics Engineering, Technical University of Denmark3
Ultra-fast Optical Communication, Department of Photonics Engineering, Technical University of Denmark4
OCTLIGHT ApS5
Surface Physics and Catalysis, Department of Physics, Technical University of Denmark6
Department of Micro- and Nanotechnology, Technical University of Denmark7
Silicon Microtechnology, Department of Micro- and Nanotechnology, Technical University of Denmark8
MEMS VCSELs are one of the most promising swept source (SS) lasers for optical coherence tomography (OCT) and one of the best candidates for future integration with endoscopes, surgical probes and achieving an integrated OCT system. However, the current MEMS-based SS are processed on the III-V wafers, which are small, expensive and challenging to work with.
Furthermore, the actuating part, i.e., the MEMS, is on the top of the structure which causes a strong dependence on packaging to decrease its sensitivity to the operating environment. This work addresses these design drawbacks and proposes a novel design framework. The proposed device uses a high contrast grating mirror on a Si MEMS stage as the bottom mirror, all of which is defined in an SOI wafer.
The SOI wafer is then bonded to an InP III-V wafer with the desired active layers, thereby sealing the MEMS. Finally, the top mirror, a dielectric DBR (7 pairs of TiO2 - SiO2), is deposited on top. The new device is based on a silicon substrate with MEMS defined on a silicon membrane in an enclosed cavity.
Thus the device is much more robust than the existing MEMS VCSELs. This design also enables either a two-way actuation on the MEMS or a smaller optical cavity (pull-away design), i.e., wider FSR (Free Spectral Range) to increase the wavelength sweep. Fabrication of the proposed device is outlined and the results of device characterization are reported.
Language: | English |
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Publisher: | SPIE - International Society for Optical Engineering |
Year: | 2018 |
Pages: | 105520I-105520I-6 |
Proceedings: | Vertical-Cavity Surface-Emitting Lasers XXII SPIE Conference |
Series: | Proceedings of Spie - the International Society for Optical Engineering |
ISBN: | 151061589X , 151061589x , 1510615903 , 9781510615892 and 9781510615908 |
ISSN: | 1996756x and 0277786x |
Types: | Conference paper |
DOI: | 10.1117/12.2289545 |
ORCIDs: | Sahoo, Hitesh Kumar , Ottaviano, Luisa , Semenova, Elizaveta , Hansen, Ole and Yvind, Kresten |