Ultra-compact titanium dioxide micro-ring resonators with sub-10-μm radius for on-chip photonics

Meicheng Fu; Yi Zheng; Gaoyuan Li; Wenjun Yi; Junli Qi; Shaojie Yin; Xiujian Li; Xiaowei Guan

doi:10.1364/PRJ.422235

Journals >Photonics Research >Volume 9 >Issue 7 >Page 1416 > Article

Photonics Research
Vol. 9, Issue 7, 1416 (2021)

Ultra-compact titanium dioxide micro-ring resonators with sub-10-μm radius for on-chip photonics

Meicheng Fu^1、2, Yi Zheng², Gaoyuan Li², Wenjun Yi¹, Junli Qi¹, Shaojie Yin³, Xiujian Li^1、4、*, and Xiaowei Guan^2、5、*

Author Affiliations

¹Department of Physics, College of Liberal Arts and Sciences, National University of Defense Technology, Changsha 410073, China

²DTU Fotonik, Technical University of Denmark, Lyngby DK-2800, Denmark

³School of Electrical Engineering, Yanshan University, Qinhuangdao 066004, China

⁴e-mail: xjli@nudt.edu.cn

⁵e-mail: xgua@fotonik.dtu.dk

show less

DOI: 10.1364/PRJ.422235 Cite this Article Set citation alerts

Meicheng Fu, Yi Zheng, Gaoyuan Li, Wenjun Yi, Junli Qi, Shaojie Yin, Xiujian Li, Xiaowei Guan. Ultra-compact titanium dioxide micro-ring resonators with sub-10-μm radius for on-chip photonics[J]. Photonics Research, 2021, 9(7): 1416 Copy Citation Text

EndNote(RIS)

BibTex

Plain Text

show less

Calculated bend loss as a function of (a) bend radius and (b) RI of a bend waveguide with a fixed width of 3 μm and height of 460 nm. Inset in (b) is the zoom-in view of the curve. Here, the simulations are carried out at 1550 nm.

Fig. 1. Calculated bend loss as a function of (a) bend radius and (b) RI of a bend waveguide with a fixed width of 3 μm and height of 460 nm. Inset in (b) is the zoom-in view of the curve. Here, the simulations are carried out at 1550 nm.

Download full size | View in the Article

Linear measurements of the fabricated TiO2 MRRs. Transmission spectra of the MRR with a radius of (a) 15 μm and (b) 10 μm. Insets are the SEM images of these MRRs. (c) SEM image and (d) transmission spectrum of the MRR with a radius of 6 μm and a pulley-type coupler, of which the coupling efficiency is shown by the red line in (d). Circles in (a), (b), and (d) indicate the resonance positions of TE0 mode. (e) Transmission spectrum (blue dot) and Lorentzian fitting curve (red line) of the 6-μm-radius MRR around the resonance of 1531.93 nm. (f) Summary of the extracted Q0 at all the resonances of the three MRRs with dashed lines indicating the average Q0 values.

Fig. 2. Linear measurements of the fabricated TiO2 MRRs. Transmission spectra of the MRR with a radius of (a) 15 μm and (b) 10 μm. Insets are the SEM images of these MRRs. (c) SEM image and (d) transmission spectrum of the MRR with a radius of 6 μm and a pulley-type coupler, of which the coupling efficiency is shown by the red line in (d). Circles in (a), (b), and (d) indicate the resonance positions of TE0 mode. (e) Transmission spectrum (blue dot) and Lorentzian fitting curve (red line) of the 6-μm-radius MRR around the resonance of 1531.93 nm. (f) Summary of the extracted Q0 at all the resonances of the three MRRs with dashed lines indicating the average Q0 values.

Download full size | View in the Article

Fig. 3. (a) Linear losses, (b) attainable power enhancement factors FE2, and (c) Purcell factors (Fp) for the TiO2 MRRs at different radii based on the measurements and fittings.

Download full size | View in the Article

Fig. 4. Schematic of the experimental setup for the FWM experiments in the fabricated ultra-compact TiO2 MRRs.

Download full size | View in the Article

Fig. 5. Output FWM spectra of the ultra-compact TiO2 MRRs with radii of (a) R=6 μm under an input pump power of 13 dBm and (b) R=10 μm under an input pump power of 16 dBm. Red and blue lines show the spectra for lights being on resonance and off resonance, respectively. (c) Measured CEs as a function of the input pump power.

Download full size | View in the Article

Fig. 6. (a) Calculated dispersions of straight and bend TiO2 waveguides with a width of 1170 nm and a height of 460 nm, and inset is the zoom-in picture of the dispersion line corresponding to R=10 μm. (b) Measured output FWM spectra for the fabricated 10-μm-radius TiO2 MRR when lights are on-resonance or off-resonance.

Download full size | View in the Article

Materials	$n_{0}$	$n_{2}$ ( $m^{2} / W$ )	$E_{g}$ (eV)	$λ_{w}$ (μm)
Si [9,10]	3.45	$4.5 \times 10^{- 18}$	1.12	1.1–6.6
SiNx [11,12]	2	$2.4 \times 10^{- 19}$	5.3	0.4–4.5
${SiO}_{2}$ [13,14]	1.44	$2.2 \times 10^{- 20}$	7.6	0.2–2.5
${Ta}_{2} O_{5}$ [14]	2.05	$7.2 \times 10^{- 19}$	3.8	0.3–8.0
${TiO}_{2}$ [15,16]	2.31	$2.3 \times 10^{- 18}$	3.1	0.4–10

Table 1. Properties of Si-Based CMOS-Compatible Dielectrics^a

View in the Article

MRR	$R$ (μm)	$Q_{0}$	${FE}^{2}$	$F_{p}$
Plasmonic WG [18]	0.5	$90 \pm 30$	Limited	$127 \pm 42$
Si [19]	1.5	9000	Limited	$\sim 59$ ^a
Thick ${Si}_{3} N_{4}$ [40]	115	$3.7 \times 10^{7}$	$\sim 7507$ ^b	$\sim 1198$ ^c
Thin ${Si}_{3} N_{4}$ [28]	1590	$5 \times 10^{6}$	$\sim 205$ ^d	9 at max
${Si}_{7} N_{3}$ [41]	50	$1.9 \times 10^{4}$	$\sim 18.1$ ^e	$\sim 3.24$ ^f
${TiO}_{2}$ [42]	150	$2 \times 10^{5}$	$\sim 38.4$ ^g	—
${TiO}_{2}$ [29]^h	136.37	$1.4 \times 10^{5}$	15	6.5
${TiO}_{2}$ [43]^I	16.37	$1.0 \times 10^{5}$	100	45
This work	10	$7.9 \times 1 0^{4}$	122	59
This work	6	$4.4 \times 1 0^{4}$	113	56