@inproceedings{6c92f5c19f7940e0b2965355ae3aa92b,
title = "Rare-earth-ion-doped ultra-narrow-linewidth lasers on a silicon chip and applications to intra-laser-cavity optical sensing",
abstract = "We report on diode-pumped distributed-feedback (DFB) and distributed-Bragg-reflector (DBR) channel waveguide lasers in Er-doped and Yb-doped Al2O3 on standard thermally oxidized silicon substrates. Uniform surface-relief Bragg gratings were patterned by laser-interference lithography and etched into the SiO2 top cladding. The maximum grating reflectivity exceeded 99%. Monolithic DFB and DBR cavities with Q-factors of up to 1.35×10^6 were realized. The Er-doped DFB laser delivered 3 mW of output power with a slope efficiency of 41% versus absorbed pump power. Single-longitudinal-mode operation at a wavelength of 1545.2 nm was achieved with an emission line width of 1.70 ± 0.58 kHz, corresponding to a laser Q-factor of 1.14×10^11. Yb-doped DFB and DBR lasers were demonstrated at wavelengths near 1020 nm with output powers of 55 mW and a slope efficiency of 67% versus launched pump power. An Yb-doped dual-wavelength laser was achieved based on the optical resonances induced by two local phase shifts in the DFB structure. A stable microwave signal at ~15 GHz with a –3-dB width of 9 kHz and a long-term frequency stability of ±2.5 MHz was created via the heterodyne photo-detection of the two laser wavelengths. By measuring changes in the microwave beat signal as the intra-cavity evanescent laser field interacts with micro-particles on the waveguide surface, we achieved real-time detection and accurate size measurement of single micro-particles with diameters ranging between 1 μm and 20 μm, which represents the typical size of many fungal and bacterial pathogens. A limit of detection of ~500 nm was deduced.",
keywords = "IOMS-APD: Active Photonic Devices, EWI-23212, Waveguide laser, METIS-296376, Distributed-feedback, IR-85265, particle sensor",
author = "Edward Bernhardi and {de Ridder}, R.M. and Kerstin Worhoff and Markus Pollnau",
year = "2013",
month = feb,
doi = "10.1117/12.2012520",
language = "English",
isbn = "978-0-81949-368-2",
series = "Proceedings of the SPIE",
publisher = "SPIE",
booktitle = "Solid State Lasers XXII",
address = "United States",
note = "SPIE Laser Source Technologies and Industrial Lasers and Applications Conference, LASE 2013, LASE ; Conference date: 02-02-2013 Through 07-02-2013",
}