Nested microring resonator with a doubled free spectral range for sensing application

Abstract

The microring resonator has received increasing attention in the optical sensing application because of its micro-size, optical property, and high sensitivity. An additional waveguide is commonly used to change the output spectra in the early research on microring resonators. In this study, we proposed a nested microring resonator that doubles the free spectral range (FSR) compared with the conventional single microring. This structure improved the sensing property as the FSR in the filter output spectra could be considered as a measurement range in the microring sensor. Moreover, the parameters including the coupling coefficient of the three coupling sections, length of the U-bend waveguide, and effective index of a waveguide were tested and carefully selected to optimize the sensing properties. The relationship between these parameters and the output spectra was demonstrated. With linear sensitivity, the structure has a good potential in sensing application.

Keywords

microring resonator / double free spectral range (FSR) / sensing application / large measurement range

References

[1] Mi K P, Kee J S, Quah J Y, Netto V, Song J, Fang Q, Fosse E M L, Lo G. Label-free aptamer sensor based on silicon microring resonators. Sensors and Actuators B, Chemical, 2013, 176(6): 552–559

[2] Jäger M, Becherer T, Bruns J, Haag R, Petermann K. Antifouling coatings on SOI microring resonators for bio sensing applications. Sensors and Actuators B, Chemical, 2015, 223(4): 400–405

[3] Zhao X, Tsai J M, Cai H, Ji X M, Zhou J, Bao M H, Huang Y P, Kwong D L, Liu A Q. A nano-opto-mechanical pressure sensor via ring resonator. Optics Express, 2012, 20(8): 8535–8542

[4] Mi G, Horvath C, Aktary M, Van V. Silicon microring refractometric sensor for atmospheric CO₂ gas monitoring. Optics Express, 2016, 24(2): 1773–1780

[5] Zang K, Zhang D, Huo Y, Chen X, Lu C Y, Fei E T, Kamins T I, Feng X, Huang Y, Harris J S. Microring bio-chemical sensor with integrated low dark current Ge photodetector. Applied Physics Letters, 2015, 106(10): 101111

[6] Mao M, Chen S, Dai D. Cascaded ring-resonators for multi-channel optical sensing with reduced temperature sensitivity. IEEE Photonics Technology Letters, 2016, 28(7): 814–817

[7] Zhang C, Chen S, Ling T, Guo L J. Review of imprinted polymer microrings as ultrasound detectors: design, fabrication, and characterization. IEEE Sensors Journal, 2015, 15(6): 3241–3248

[8] Prasad P R, Selvaraja S K, Varma M M. High precision measurement of intensity peak shifts in tunable cascaded microring intensity sensors. Optics Letters, 2016, 41(14): 3153–3156

[9] Xu Q, Fattal D, Beausoleil R G. Silicon microring resonators with 1.5-microm radius. Optics Express, 2008, 16(6): 4309–4315

[10] Lu Y, Fu X, Chu D, Wen W, Yao J. Fano resonance and spectral compression in a ring resonator drop filter with feedback. Optics Communications, 2011, 284(1): 476–479

[11] Li Z, Li X, SunY, LiS, Zheng W. Doubled free spectral range of single microring resonator filter. Acta Optica Sinica, 2012, 32(7): 224–229

[12] Xiang X Y, Wang K R, Yuan J H, Jin B Y, Sang X Z, YuC X. Highly sensitive digital optical sensor with large measurement range based on the dual-microring resonator with waveguide-coupled feedback. Chinese Physics B, 2014, 23(3): 034206 

Acknowledgements

This study was supported by the National Natural Science Foundation of China (Grant Nos. 61601253 and 61501271) and K. C. Wong Magna Fund in Ningbo University.

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2017 Higher Education Press and Springer-Verlag Berlin Heidelberg