Yingzhan Yan

Packaged silica microsphere-taper coupling system for robust thermal sensing application

We propose and realize a novel packaged microsphere-taper coupling structure (PMTCS) with a high quality factor (Q) up to 5×10(6) by using the low refractive index (RI) ultraviolet (UV) glue as the coating material. The optical loss of the PMTCS is analyzed experimentally and theoretically, which indicate that the Q is limited by the glue absorption and the radiation loss. Moreover, to verify the practicability of the PMTCS, thermal sensing experiments are carried out, showing the excellent convenience and anti-jamming ability of the PMTCS with a high temperature resolution of 1.1×10(-3) ◦C. The experiments also demonstrate that the PMTCS holds predominant advantages, such as the robustness, mobility, isolation, and the PMTCS can maintain the high Q for a long time. The above advantages make the PMTCS strikingly attractive and potential in the fiber-integrated sensors and laser.

Robust Spot-Packaged Microsphere-Taper Coupling Structure for In-Line Optical Sensors

We propose and realize a spot-packaged structure for the microsphere-taper coupling system by only encapsulating and solidifying the coupling region with low refractive index polymer as the package material. After spot-package, ultrahigh quality factor ( >; 107) is obtained with the microsphere diameters around 300 μm. The robustness of the spot-packaged structure is also tested, demonstrating the remarkable anti-tensile strength ability with the bearable loaded force larger than 0.05 N for a packaged structure with the spot-package area larger than 30 μm2. In addition, the spot-packaged structure is integrated with standard fiber, promising in in-line optical practical evanescent field sensing applications, especially in harsh detecting environments demanding high overload resistance.

Design and modeling of a novel micro-displacement sensor based optical frequency comb

Pumping a single-mode, tunable, external-cavity laser to excite the whispering gallery modes (WGM) of micro ring resonators (MRRs), a series of equidistant, wide free spectrum range (FSR) can be observed. Frequency shift of FSR can be used to feedback external changes, making MRR very promising in high-sensitivity sensing. In this paper, a novel displacement sensor composed of a micro ring resonator and a waveguide is presented and a designing route for this sensor is discussed. Based on mathematical analysis and the beam propagation methods (BPM), the major parameters including the geometry of MRR and micro cantilever are investigated in detail. Materials selection and fabrication method under current processing technic are also presented. For the typical structure in this paper, the final Q factor is estimated approximately 103 in theory at the wavelength of 1.5μm.Displacement alteration of cantilever is 0.296x10-6m - 0.535x10-5m approximately corresponding 10-8-10-6N force loading. The shift of transmission spectrum is about 3.9nm versus perimeter of MRR changing 1μm.

A stable frequency references platform based on packaged microsphere-taper coupling system

“Whispering gallery modes” (WGM) optical micro- and nano resonators are important category in nanophotonics researches. The ultra-high quality factor (Q) makes them promising ranging from sensors, filters to low threshold sources. In the above supplications, the frequency stability of the WGM is critical, which is determined by several factors. In this paper, using the microsphere resonator we construct a robust packaged microsphere-taper coupling system (MTCS) to stabilize the resonant WGMs. Furthermore, a stable frequency references platform based on the packaged microcavity unit is constructed. This stable frequency references platform can eliminate the noise of the WGM, and promote the microresonator researches.

High-Q maintenance of microcavity by using a sealed and packaged structure

The high-Q maintenance of microcavities greatly challenges the microresonator-based practical application. In this paper, the Q spoiling factors are demonstrated experimentally to show the Q spoiling which originated from the water and the particulate in the surroundings. Then we propose and realize the Q maintenance through constructing a sealed and packaged microcavity regime. In the packaged structure the Q decreases a little but a high Q larger than 106 can be achieved continuously. Moreover, the sealed structure has good performance to maintain the high Q for a long time with the standard deviation about 104, because the Q spoiling factors are isolated by the package layer. Additionally, the package also enhances the robustness. These merits can promote the practical application of the microcavities.

A novel packaging method for stable microsphere coupling system

We experimentally package the microaphere coupling system using UV glue with low refractive index about 1.32. Experimental results demonstrated that the Q-factor of the packaged coupling system is about one order of magnitude lower than that of non-packaged sample but continuously tested to be 107 or 108. In microcavity application research, such as resonant microcavities optical gyroscopes, this package method not only fixes the coupling system, enhancing its anti-seismic dynamic ability, but also isolates the whole coupling system from external environment. Therefore, this package method can make coupling system stable, and it will greatly promote optical research from fundamental study to application research.

Packaging and isolating microsphere coupling system

Optical microresonantors are widely researched for a number of applications, especially microcavity-based sensors. However, the transmission characteristic is prone to be affected by the surrounding. In this paper, a novel method to isolating the microcavity coupling system is presented. The Selection principle for packaging material is discussed and the details of packaging process are introduced. Resonant whispering gallery models (WGMs) are tested for microsphere system, no packaging and packaged respectively. Proof tests were also carried out to check the isolation. Experiments showed that, package the coupling system is an effective method to isolate coupling system from surrounding environment. Moreover, the packaged body was also function as a fixed retainer, used for fix the position of microcavity and tapered fiber.

The research of a novel gyroscope based on high Q micro-resonator

Optical microcavities confine light to small model volumes and have ultrahigh quality factor (Q), especially microtoroid cavities, having very broad application prospects. In this paper, a micro-optical-electro-mechanical system (MOEMS) gyroscope was developed taking a new optical microcavity-planar microdisk cavity as the core sensing element. To obtain resonance curve, a resonant cavity proof-of-principle experiment was performed. As the light source and planar microdisk cavity dimensions have a decisive influence on the Q value of microcavity and angular rate measurement limit of gyroscope, a method was discussed that using traditional F-P cavity resonance curve for optimization of planar microdisk cavity geometric parameters.

A neoteric packeged structure to eliminate the spoiling effect from external environment

We proposed a novel dielectric silica packaged microsphere-taper coupling structure to protect the coupling system from damage and avoid the spoiling effects on the Q. Here, several factors such as water vapor and dust affecting the Q of optical microsphere cavities were analyzed theoretically and experimentally. Experiments demonstrated that the water vapor and dust around the microsphere cavity have great effects on the Q, which were mainly the optical absorption loss of water and scattering loss of dust. However, the packaged body isolated the microsphere-taper from the outside surroundings, and maintained the Q above 106 for a long time. Therefore, it will greatly promote optical research from fundamental study to application research.

Package technology for microcavities

Although Microcavities are promising in a variety of novel devices, there is slow development in microcavity based practical devices due to the lack of the package technology. In this paper, for the first time, we demonstrate the package technology for the microcavity coupling system to promote the development of the microcavity based practical applications. The package process are illustrated in detail. The changes which result from the package are also discussed. In addition, the advantages of the packaged structure are characterized, including the Q maintenance, robustness and the convenience. These advantages make this packaged structure promising in microcavity based practical devices.