Suspended nanocrystalline diamond ridge waveguides designed for the mid-infrared
Suspended nanocrystalline diamond ridge waveguides designed for the mid-infrared
A comprehensive study and design of air-clad suspended ridge diamond waveguides for operation across the 2.5-16 μm spectral range is presented, specifically targeting nanocrystalline diamond (NCD) thin films directly grown on silicon substrates. Three film thicknesses of 520, 1000 and 2000 nm are considered, to cover overlapping sub-bands of 2.5-5, 4-9 and 8-16 μm, respectively. Within each sub-band, the waveguide dimensions for single mode quasi-TE operation are found and the waveguide material losses and bending losses are estimated at each design point. In addition, in each case the minimum required undercut depth and etch hole placement for optical isolation of the waveguide mode from the silicon substrate is also quantified. We also estimate the losses associated with scattering from surface roughness, which is an unavoidable byproduct of the NCD thin film growth process. Our results indicate that despite the relatively low film thickness-to-wavelength ratio, mechanically stable waveguides with good optical confinement and low material and bending losses can be realised to cover the full 2.5-16 μm range. In addition, scattering loss estimations predict a drastic drop in roughness-induced scattering losses above 6 μm, even for relatively rough films. In addition to highlighting the utility of suspended NCD as a versatile platform for mid-infrared integrated photonics, the approaches and results presented here can be used to inform the design of suspended air-clad waveguides in other material platforms.
Diamond photonics, Group IV photonics, Infrared integrated photonics, Suspended waveguides
Rahmati, A.T.
92ace848-69b1-4406-a450-b709dcceecf2
Mashanovich, G.Z.
c806e262-af80-4836-b96f-319425060051
Nezhad, M.P.
e1e2afc2-4dd7-4b72-8de8-f5975ea0e01d
21 June 2021
Rahmati, A.T.
92ace848-69b1-4406-a450-b709dcceecf2
Mashanovich, G.Z.
c806e262-af80-4836-b96f-319425060051
Nezhad, M.P.
e1e2afc2-4dd7-4b72-8de8-f5975ea0e01d
Rahmati, A.T., Mashanovich, G.Z. and Nezhad, M.P.
(2021)
Suspended nanocrystalline diamond ridge waveguides designed for the mid-infrared.
Journal of Optics (United Kingdom), 23 (7), [075801].
(doi:10.1088/2040-8986/ac0873).
Abstract
A comprehensive study and design of air-clad suspended ridge diamond waveguides for operation across the 2.5-16 μm spectral range is presented, specifically targeting nanocrystalline diamond (NCD) thin films directly grown on silicon substrates. Three film thicknesses of 520, 1000 and 2000 nm are considered, to cover overlapping sub-bands of 2.5-5, 4-9 and 8-16 μm, respectively. Within each sub-band, the waveguide dimensions for single mode quasi-TE operation are found and the waveguide material losses and bending losses are estimated at each design point. In addition, in each case the minimum required undercut depth and etch hole placement for optical isolation of the waveguide mode from the silicon substrate is also quantified. We also estimate the losses associated with scattering from surface roughness, which is an unavoidable byproduct of the NCD thin film growth process. Our results indicate that despite the relatively low film thickness-to-wavelength ratio, mechanically stable waveguides with good optical confinement and low material and bending losses can be realised to cover the full 2.5-16 μm range. In addition, scattering loss estimations predict a drastic drop in roughness-induced scattering losses above 6 μm, even for relatively rough films. In addition to highlighting the utility of suspended NCD as a versatile platform for mid-infrared integrated photonics, the approaches and results presented here can be used to inform the design of suspended air-clad waveguides in other material platforms.
Text
Rahmati_2021_J._Opt._23_075801
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Accepted/In Press date: 4 June 2021
Published date: 21 June 2021
Keywords:
Diamond photonics, Group IV photonics, Infrared integrated photonics, Suspended waveguides
Identifiers
Local EPrints ID: 481691
URI: http://eprints.soton.ac.uk/id/eprint/481691
ISSN: 2040-8978
PURE UUID: ddfb06e0-4a16-4aaf-b421-df1dae9d8a8f
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Date deposited: 06 Sep 2023 16:48
Last modified: 29 Oct 2024 02:45
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Author:
A.T. Rahmati
Author:
G.Z. Mashanovich
Author:
M.P. Nezhad
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