Spectroscopy of thulium-doped tantalum pentoxide waveguides on silicon

Abstract

The spectroscopic properties and laser operation of thulium-doped tantalum pentoxide (Tm:Ta 2 O 5) waveguides are reported in this paper. Fluorescence ranging from 1600 nm to 2200 nm, corresponding to the 3 F 4 → 3 H 6 transition was observed from 3 wt% Tm:Ta 2 O 5 waveguides pumped at a wavelength of 795 nm. Measurements of excited-state lifetime, the emission and absorption spectra, with subsequent calculation of the crosssections for the deposited films, reveal its potential as a gain medium. Laser operation at a wavelength of 1865 nm was obtained with feedback from the polished end faces alone, demonstrating gain of >9 dB/cm.

Lasing in a Hybrid Rare‐Earth Silicon Microdisk

“…Tm 3+ ions exhibit relatively shifted absorption and emission spectra (resulting in low ground state absorption at longer laser wavelengths), minimal quenching effects at high ion concentrations and emission near the edge of silicon's low twophoton absorption window, allowing for straightforward population inversion in the laser cavity and efficient optical pumping and lasing. However, while high efficiency on-chip thulium lasers have been demonstrated in crystalline waveguides [40] and dielectric host materials on silicon substrates, [41][42][43] thulium is relatively unexplored as a laser ion in an SOI platform. Importantly, here a standard silicon photonics foundry process was used to fabricate the disk platform and bus waveguide, which enables such hybrid lasers to be co-integrated with other passive and active silicon photonic devices on the same chip.…”