I Demirtzioglou, C Lacava, A Shakoor, A Khokhar, Y Jung, D J Thomson, P Petropoulos Apodized silicon photonic grating couplers for mode-order conversion Journal Article Photonics Research, 7 (9), pp. 1036–1041, 2019. Abstract | Links | Tags: coupler, intermodal, multimode, silicon, Silicon photonics, surface coupler, surface gratings @article{Demirtzioglou2019,
title = {Apodized silicon photonic grating couplers for mode-order conversion},
author = {I Demirtzioglou and C Lacava and A Shakoor and A Khokhar and Y Jung and D J Thomson and P Petropoulos},
doi = {10.1364/PRJ.7.001036},
year = {2019},
date = {2019-01-01},
journal = {Photonics Research},
volume = {7},
number = {9},
pages = {1036--1041},
abstract = {An out-of-plane silicon grating coupler capable of mode-order conversion at the chip–fiber interface is designed and fabricated. Optimization of the structure is performed through finite-difference time-domain simulations, and the final device is characterized through far-field profile and transmission measurements. A coupling loss of 3.1 dB to a commercial two-mode fiber is measured for a single TE0 → LP11 mode conversion grating, which includes a conversion penalty of 1.3 dB. Far-field patterns of the excited LP11 mode profile are also reported.},
keywords = {coupler, intermodal, multimode, silicon, Silicon photonics, surface coupler, surface gratings},
pubstate = {published},
tppubtype = {article}
}
An out-of-plane silicon grating coupler capable of mode-order conversion at the chip–fiber interface is designed and fabricated. Optimization of the structure is performed through finite-difference time-domain simulations, and the final device is characterized through far-field profile and transmission measurements. A coupling loss of 3.1 dB to a commercial two-mode fiber is measured for a single TE0 → LP11 mode conversion grating, which includes a conversion penalty of 1.3 dB. Far-field patterns of the excited LP11 mode profile are also reported. |
A Bozzola, L Carroll, D Gerace, I Cristiani, L C Andreani Optimising apodized grating couplers in a pure SOI platform to -0.5 dB coupling efficiency Journal Article Optics Express, 23 (12), pp. 16289–16304, 2015. Abstract | Links | Tags: coupler, Silicon photonics, surface coupler, surface gratings @article{Bozzola2015,
title = {Optimising apodized grating couplers in a pure SOI platform to -0.5 dB coupling efficiency},
author = {A Bozzola and L Carroll and D Gerace and I Cristiani and L C Andreani},
doi = {10.1364/OE.23.016289},
year = {2015},
date = {2015-01-01},
journal = {Optics Express},
volume = {23},
number = {12},
pages = {16289--16304},
abstract = {We present a theoretical optimisation of 1D apodized grating couplers in a "pure" Silicon-On-Insulator (SOI) architecture, i.e. without any bottom reflector element, by means of a general mutative method. We perform a comprehensive 2D Finite Difference Time Domain study of chirped and apodized grating couplers in 220 nm SOI, and demonstrate that the global maximum coupling efficiency in that platform is capped to 65% (-1.9 dB). Moving to designs with thicker Si-layers, we identify a new record design in 340 nm SOI, with a simulated coupling efficiency of 89% (-0.5 dB). Going to thicker Si layers does not further improve the efficiency, implying that -0.5 dB may be a global maximum for a grating coupler in SOI without a bottom-reflector. Even after allowing for 193 nm UV-lithographic fabrication constraints, the 340 nm design still offers -0.7 dB efficiency. These new apodized designs are the first pure SOI couplers compatible with deep-UV lithography to offer better than -1 dB insertion losses.With only very minor changes to existing deposition and lithography recipes, they are compatible with the multi-project wafer runs already offered by Si-Photonics foundries.},
keywords = {coupler, Silicon photonics, surface coupler, surface gratings},
pubstate = {published},
tppubtype = {article}
}
We present a theoretical optimisation of 1D apodized grating couplers in a "pure" Silicon-On-Insulator (SOI) architecture, i.e. without any bottom reflector element, by means of a general mutative method. We perform a comprehensive 2D Finite Difference Time Domain study of chirped and apodized grating couplers in 220 nm SOI, and demonstrate that the global maximum coupling efficiency in that platform is capped to 65% (-1.9 dB). Moving to designs with thicker Si-layers, we identify a new record design in 340 nm SOI, with a simulated coupling efficiency of 89% (-0.5 dB). Going to thicker Si layers does not further improve the efficiency, implying that -0.5 dB may be a global maximum for a grating coupler in SOI without a bottom-reflector. Even after allowing for 193 nm UV-lithographic fabrication constraints, the 340 nm design still offers -0.7 dB efficiency. These new apodized designs are the first pure SOI couplers compatible with deep-UV lithography to offer better than -1 dB insertion losses.With only very minor changes to existing deposition and lithography recipes, they are compatible with the multi-project wafer runs already offered by Si-Photonics foundries. |
