arXiv subjects

Purnima Sethi

Publications and source records attributed to Purnima Sethi.

3 recordsLinked to original sources

arXiv2019

Alignment Tolerant Broadband Compact Taper for Low-Loss Coupling to a Silicon-on-Insulator Photonic Wire Waveguide

We experimentally demonstrate a broadband, fabrication tolerant, CMOS compatible compact silicon waveguide taper (34.2 um) in silicon-on-insulator wire waveguides. The taper works on multi-mode interference along the length of the taper. A single taper design has a broadband operation with coupling efficiency >70% over 700 nm that can be used in O, C and L-band. The compact taper is highly tolerant to fabrication variations; >100 nm change in the taper and end waveguide width varies the taper transmission by <5%. The footprint of the device i.e. taper along with the linear gratings is ~ 442 m2; i.e. 11.5X smaller than the adiabatic taper. The taper with linear gratings provides comparable coupling efficiency as standardly used focusing gratings. We have also compared the translational and rotational alignment tolerance of the focusing grating with the linear grating.

physics.app-ph↗

arXiv2017

Compact Broadband Low-Loss Taper for Coupling to a Silicon Nitride Photonic Wire

We demonstrate an ultra-compact waveguide taper in Silicon Nitride platform. The proposed taper provides a coupling-efficiency of 95% at a length of 19.5 um in comparison to the standard linear taper of length 50 um that connects a 10 um wide waveguide to a 1 um wide photonic wire. The taper has a spectral response > 75% spanning over 800 nm and resilience to fabrication variations; >200 nm change in taper and end waveguide width varies transmission by <5%. We experimentally demonstrate taper insertion loss of <0.1 dB/transition for a taper as short as 19.5 um, and reduces the footprint of the photonic device by 50.8% compared to the standard adiabatic taper. To the best of our knowledge, the proposed taper is the shortest waveguide taper ever reported in Silicon Nitride.

physics.app-ph↗

arXiv2017

Ultra-compact low-loss broadband waveguide taper in silicon-on-insulator

A novel design of large bandwidth, fabrication tolerant, CMOS-compatible compact tapers (15 um) have been proposed and experimentally demonstrated in silicon-on-insulator. The proposed taper along with linear grating couplers for spot-size conversion exhibits no degradation in the coupling efficiency compared to a standard focusing grating in 1550 nm band. A single taper design has a broadband operation over 600 nm that can be used in O, C and L-band. The proposed compact taper is highly tolerant to fabrication variations; 80 nm change in the taper width and 200 nm in end waveguide width varies the taper transmission by <0.4 dB. The footprint of the device i.e. taper along with the linear gratings is ~ 250 μm2; this is 20X smaller than the adiabatic taper and 2X smaller than the focusing grating coupler.

physics.optics↗