Waveguide fabrication methods in dielectric solids

Pollnau, Markus

doi:10.1007/1-4020-4789-4_18

Cited by 1 publication

(1 citation statement)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While processes such as laser ablation, ion beam implantation and reactive ion etching or wet chemical etching are limited to surface or near-surface structures, generation of waveguides buried deeply in the bulk of these substrates was demonstrated by means of proton implantation and femtosecond laser-based refractive index modification [31,32]. Since buried structures generally promise superior performance due to decreased waveguide asymmetry and, due to the lack of surface interaction, reduced scattering effects, femtosecond laser-based fabrication methods are expected to pave the way towards 3D optical integrated circuits [33]. Bérubé et al recently demonstrated the first waveguide, buried within a bulk and undoped sapphire substrate, exhibiting single-mode operation at a wavelength of 2850 nm by generating a depressed cladding structure around the waveguide's core via femtosecond laser-based refractive index modification of the material [34].…”

Section: Introductionmentioning

confidence: 99%

Sapphire Photonic Crystal Waveguides with Integrated Bragg Grating Structure

et al. 2022

View full text Add to dashboard Cite

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.

show abstract