Ultrahigh Q SOI ring resonator with a Hermite or B-spline curved waveguide

Two new, to the best of our knowledge, designs for a huge, single-mode operation, ultrahigh quality factor SOI ring resonators based on the 90 degrees bend of the B-spline curve and the Hermite curve were demonstrated. The ring resonators comprise multimode straight strip waveguides (MMWG), single-mode strip waveguides (SMWG), 90 degrees bends, and tapers. The TE0-TE0 transmission loss of the bends can reach 0.000013 dB and 0.000091 dB, and the TE0-TE1 excitation ratios reach -48 dB and -50 dB, respectively, when the bends were designed using the Hermite curve or B-spline curve. Two SOI ring resonators of about 3.00 cm length consisting of the structures mentioned above are manufactured. The first was made up of Hermite curves with 90 degrees bends. It could achieve a Q factor of 4.65 x 106 and a free spectrum range (FSR) of 0.025 nm. The second one employed B-spline curves with 90 degrees bends. It could reach a Q factor of 4.37 x 106 and FSR of 0.022 nm. (c) 2024 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.