Design and Analysis of Ring Resonator with Thermal Tuning

A type of waveguide ring resonator, based on Er3+/Yb3+ co-doped phosphate glass and using thermal-optical effect as tuning manner, is brought up. The ring resonator is composed of two straight waveguides and a ring waveguide with radius of 400 μm. Electrode is evaporated on the top of the waveguide to achieve thermal tuning. Firstly, the filtering scheme of the ring resonator is analyzed, then how parameters of the electrode influence the filtering characteristics is discussed.

Thermal-optic tuning cascaded double ring optical sensor based on wavelength interrogation

Based on the Vernier effect of the cascaded double ring resonator(CDRR) sensor,a sensor consisting of a microfluidic control system,a sensing ring,and a reference ring with a micro-heater for thermal tuning is proposed in this paper.In wavelength interrogation,a broadband spectrometer or a large tunable range laser is not required.The shift of the output spectrum caused by the refractive index change of the sample is converted into the change of the electric power by the thermal tuning heater.Due to the Vernier effect,the sensitivity of the sensor is 20 times higher than that of the single ring.The spectral envelope of the thermal-optic tuning of the sensor was fitted by a Gaussian function in the wavelength range of8 nm.The experimental results showed that the sensitivity was 33.703 W/RIU,and the limit of detection was 1.34×10-5 RIU.

Deliberation between PM1 and PM2.5 as air quality indicators based on comprehensive characterization of urban aerosols in Bangkok, Thailand

Urban ambient aerosols in the size range below 10 μm were measured and sampled for further evalua- tion （by Raman and Thermal-Optical analysis） of the collected material. The presented data shows that monitoring number and/or surface area concentrations besides the mass concentration provides valu- able information for a meaningful assessment of the actual ambient air quality. The aim of the study was to characterize the urban aerosols using various instruments, methods, and sampling conditions, and to determine whether a split of the PMzs size fraction at PM1 may deliver a more sensible indication of the actual air quality than the current standard of monitoring PMzs. We found substantial differences relating to this split. PM2.5 data frequently include particles from both mechanical and combustion processes, PM1 measurements can be used to better distinguish particles derived from these two sources. We measured number concentrations of PM1 with PM2.5-1 concurrently with particle mass concentration and found that the typical average particle diameter by mass in the urban aerosols investigated was in the range of 120 nm; this corresponded well with the particle number size distributions measured in real time. Raman spectral analysis and thermal-optical evaluation of the sampled material also suggested that it would be sensible to split the measurement of the PM2.5 fraction into PM1 and PM2.s-1 size fractions, especially for analysis of carbonaceous aerosol components using the DRI thermal/optical reflectance carbon analysis system

Tunable fiber-tip lens based on thermo-optic effect of amorphous silicon

We theoretically demonstrate a compact all-dielectric metasurface fiber-tip lens composed of sub-wavelength amorphous silicon on the end face of a multimode fiber.The full 2πphase control was realized by varying the widths of resonant units.The tunable focal length is achieved by using the thermal-optic effect of amorphous silicon.The focal length increases from 309μm to 407μm when the temperature changes by 300 K.The temperature controlled all-fiber integrated lens is compact and with high efficiency and provides an excellent platform of a fiber-tip lab.Meanwhile,the proposed fiber lens does not have any structural changes during dynamic tuning,which improves the durability and repeatability of the devices.