Suspended ultra-small disk resonator on silicon for optical sensing

Abstract

An ultra-small disk resonator consisting of a suspended silicon disk with a submicron bending radius sitting on an SiO(2) pedestal is demonstrated experimentally. An asymmetrical suspended rib waveguide is integrated as the access waveguide for the suspended submicron disk resonator, which is used to realize an ultra-small optical sensor with an improved sensitivity due to the enhanced evanescent field interaction with the analyte. The present optical sensor also has a large measurement range because of the ultra-large free-spectral range of the submicron-disk resonator. As an example, a suspended submicron disk sensor with a bending radius of 0.8 μm is designed, fabricated, and characterized. The concentration of NaCl aqueous solution and organic liquids is measured with the suspended submicron-disk sensor, and the measured sensitivity is about 130 nm/RIU, which agrees well with the simulation value.

Thermally tunable silicon photonic microdisk resonator with transparent graphene nanoheaters

“…1,2 Among various silicon photonic integrated devices, an optical micro-cavity is well known as a versatile element to realize many functionality components, including optical filters/switches, 3,4 optical modulators 5 and optical sensors. 6 Since silicon has a large heat conductivity (~149W/m•K) and a large thermo-optical (TO) coefficient (~1.8×10 -4 /K at the wavelength of 1.55μm), 7 it is possible and beneficial to achieve efficient thermal tuning in silicon micro-cavities. Traditionally, metal heaters are usually used for thermally tuning silicon micro-cavities, and a thick SiO 2 upper-cladding layer is required between the metal heater and the silicon core to isolate metal absorption.…”

Optical Characteristics of Unidirectional Single-mode Lasing Square Ring Cavities

“…집적 광학의 원리를 기반으로 마이크로 공진 소자는 optical switching, interconnection, bio-sensing [1][2][3][4][5][6][7][8][9] 등에서의 광대한 응 용가능성 때문에, 링 [1][2][3][4][5][6][7] , 디스크 [8] , 구형 [9,10] 등의 다양한 구 조로 연구되고 있다. 여러 광학 공진기 중에서 링 공진기는 높은 Q값과 좁은 선폭의 발진 특성으로 잘 알려져 있다.…”

Improving the detection limit for on-chip photonic sensors based on subwavelength grating racetrack resonators

“…Various resonance structures have been proposed to optimize the performance of these sensors, including two-dimensional photonic crystal (PhC) micro-cavity resonators [1][2][3][4], one dimensional PhC nanobeam resonators [5][6][7][8], disk resonators [9,10], and ring resonators [11][12][13]. High sensitivity (S) is required in those sensors, which strongly depends on optical loss, light polarization, and the overlap between light and the surrounding material.…”

“…Several structures and methods have been proposed and demonstrated to enhance the sensitivity. These include ring slot resonators [14,15], slot waveguides [16], nano-holes [17], low index modes [8], slow light effect [18] and transverse magnetic (TM) guide modes [9,10].…”