Sapphire Photonic Crystal Waveguides with Integrated Bragg Grating Structure

Kefer S, Roth GL, Zettl J, Schmauß B, Hellmann R (2022)

Publication Type: Journal article

Publication year: 2022

Journal

Photonics MDPI

Book Volume: 9

Article Number: 234

Journal Issue: 4

DOI: 10.3390/photonics9040234

Abstract

This contribution demonstrates photonic crystal waveguides generated within bulk planar sapphire substrates. A femtosecond laser is used to modify the refractive index in a hexagonal pattern around the pristine waveguide core. Near-field measurements reveal single-mode behavior at a wavelength of 1550 nm and the possibility to adapt the mode-field diameter. Based on far-field examinations, the effective refractive index contrast between the pristine waveguide core and depressed cladding is estimated to 3·10−4. Additionally, Bragg gratings are generated within the waveguide core. Due to the inherent birefringence of Al2O3, the gratings exhibit two distinct wavelengths of main reflection. Each reflection peak exhibits a narrow spectral full width at a half maximum of 130 pm and can be selectively addressed by exciting the birefringent waveguide with appropriately polarized light. Furthermore, a waveguide attenuation of 1 dB cm−1 is determined.

Authors with CRIS profile

Bernhard Schmauß Professur für Hochfrequenztechnik mit dem Schwerpunkt Optische Hochfrequenztechnik und Photonik

Involved external institutions

Technische Hochschule Aschaffenburg DE Germany (DE)

How to cite

APA:

Kefer, S., Roth, G.L., Zettl, J., Schmauß, B., & Hellmann, R. (2022). Sapphire Photonic Crystal Waveguides with Integrated Bragg Grating Structure. Photonics, 9(4). https://dx.doi.org/10.3390/photonics9040234

MLA:

Kefer, Stefan, et al. "Sapphire Photonic Crystal Waveguides with Integrated Bragg Grating Structure." Photonics 9.4 (2022).

BibTeX: Download