Title | Femtosecond laser inscription of depressed cladding single-mode mid-infrared waveguides in sapphire. |
Publication Type | Journal Article |
Year of Publication | 2019 |
Authors | Bérubé, Jean-Philippe, Jerome Lapointe, Albert Dupont, Martin Bernier, and Réal Vallée |
Journal | Opt Lett |
Volume | 44 |
Issue | 1 |
Pagination | 37-40 |
Date Published | 2019 Jan 01 |
ISSN | 1539-4794 |
Abstract | Mid-infrared optical waveguides were inscribed in sapphire with femtosecond pulses at 515 nm. We show that such pulses induce a smooth negative refractive index change allowing for the inscription of a depressed cladding waveguide by closely overlapping the corresponding type I modification traces. The resulting structure consists of a highly symmetrical, uniform, and homogeneous waveguide. The size and numerical aperture of the waveguides were tailored to achieve efficient transmission in the mid-infrared. Single mode operation at a wavelength of 2850 nm and propagation loss of <0.37 dB/cm are reported for a 33 mm long depressed cladding waveguide. Thermal annealing was performed, and the refractive index contrast was still preserved to 50% (i.e., Δn=∼2.5×10) up to 1400°C. |
DOI | 10.1364/OL.44.000037 |
Alternate Journal | Opt Lett |
PubMed ID | 30645539 |