title: Biosensing using microring resonator interferograms.
abstract: Optical low-coherence interferometry (OLCI) takes advantage of the variation in refractive index in silicon-wire microring resonator (MRR) effective lengths to perform glucose biosensing using MRR interferograms. The MRR quality factor (Q), proportional to the effective length, could be improved using the silicon-wire propagation loss and coupling ratio from the MRR coupler. Our study showed that multimode interference (MMI) performed well in broad band response, but the splitting ratio drifted to 75/25 due to the stress issue. The glucose sensing sensitivity demonstrated 0.00279 meter per refractive-index-unit (RIU) with a Q factor of ~30,000 under transverse electric polarization. The 1,310 nm DFB laser was built in the OLCI system as the optical ruler achieving 655 nm characterization accuracy. The lowest sensing limitation was therefore 2 × 10-4 RIU. Moreover, the MRR effective length from the glucose sensitivity could be utilized to experimentally demonstrate the silicon wire effective refractive index with a width of 0.45 mm and height of 0.26 mm.
authors.affiliation: Department of Electronic Engineering, National Taiwan University of Science and Technology, No.43, Sec. 4, Keelung Rd., Taipei 10607, Taiwan. shsu@mail.ntust.edu.tw.
authors.forename: Shih-Hsiang
authors.initials: SH
authors.lastname: Hsu
authors.affiliation: Department of Electronic Engineering, National Taiwan University of Science and Technology, No.43, Sec. 4, Keelung Rd., Taipei 10607, Taiwan. d9902308@mail.ntust.edu.tw.
authors.forename: Yung-Chia
authors.initials: YC
authors.lastname: Yang
authors.affiliation: Department of Electronic Engineering, National Taiwan University of Science and Technology, No.43, Sec. 4, Keelung Rd., Taipei 10607, Taiwan. s90045555@yahoo.com.tw.
authors.forename: Yu-Hou
authors.initials: YH
authors.lastname: Su
authors.affiliation: Department of Electronic Engineering, National Taiwan University of Science and Technology, No.43, Sec. 4, Keelung Rd., Taipei 10607, Taiwan. s960318@gmail.com.
authors.forename: Sheng-Min
authors.initials: SM
authors.lastname: Wang
authors.affiliation: Department of Electronic Engineering, National Taiwan University of Science and Technology, No.43, Sec. 4, Keelung Rd., Taipei 10607, Taiwan. forsam10@gmail.com.
authors.forename: Shih-An
authors.initials: SA
authors.lastname: Huang
authors.affiliation: Department of Electronic Engineering, National Taiwan University of Science and Technology, No.43, Sec. 4, Keelung Rd., Taipei 10607, Taiwan. PhotonicsNTUST@gmail.com.
authors.forename: Ching-Yu
authors.initials: CY
authors.lastname: Lin
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D004867:Equipment Design; D007368:Interferometry / Q000379:methods*