This PDF file contains the front matter associated with SPIE Proceedings Volume 9285 including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

Speckle patterns observed in an output light spot from an optical fiber are likely to be changed due to external disturbances applied to the fiber, and such changes can be utilized for sensing applications. In this paper, certain load was applied onto an optical fiber through which laser beams emitted from a laser diode were propagating, and changes in speckle patterns observed in the output light spot from the optical fiber were investigated as image data via a CCD camera. For the purpose of realizing effective load application onto an optical fiber, a load application section was employed in which several ridges were provided onto opposite flat plates. A jacket-covered communication-grade multi-mode glass optical fiber was placed in the load application section so that corrugated bending of the fiber was intentionally induced via load application due to the ridges. The obtained results from appropriate image processing showed that the number of speckles in the observed patterns decreased upon load application (up to 15kg) onto the optical fiber with satisfactory repeatability. The load was then reduced from the total of 15kg, and the number of speckles was found to recover. With different arrangements of the optical fiber in the load application section in which the number of load application points was altered, slight differences in the observed characteristics were recognized. Thus, there are possibilities of utilizing changes in speckle patterns observed in an output light spot from an optical fiber for sensing of load application onto the optical fiber by employing appropriate load application arrangements.

In this paper, gas sensor array with micro-well was designed and prepared by Micro Electro-Mechanical Systems (MEMS) technology. The micro-well and interdigital electrodes of sensor array were prepared using photolithography process, reactive ion etching (RIE) process, wet etching and conventional vacuum evaporation. In the manufacture process of the gas sensor array, KOH wet etching process was mainly discussed. The optimum etching processing parameters were as follows: 30 wt% KOH solution at 80 °C, a cooling back-flow device and a magnetic stirrer. The multi-walled carbon nanotubes (MWCNTs)-polyethyleneoxide (PEO) and MWNTs-Polyvinylpyrrolidone (PVP) composite films were utilized as sensitive layers to test gas-sensing properties. Response performances of MWCNTs- PEO and MWNTs-PVP composite films to toluene vapor and methanol vapor at room temperature were investigated. The results revealed that the sensor array showed a larger sensitivity to toluene vapor than to methanol vapor. In addition, the sensing mechanisms were studied as well.

Based on the environment requirements in seaside there exists static and dynamic seal designing for the photoelectric Theodolite. Static seal designing emphatically includes the designing of o-ring size and mechanical property analysis of o-ring seal, which is difficult to adopt conventional dynamic seal to meet the requirements. According to practical application, the combination of the radial labyrinth seal and high quality felt seal are designed. The combination seal which better solves the seal problem of narrow radial size is a good way of dynamic seal. At the same time, there is engineering practice needing to proof the radial labyrinth seal.

In this paper, the tunable property of two complementary frequency selective surface (CFSS)designs is presented. The unit cell of each design comprises of rotationally symmetric element. CFSS is a double layer structure with a patch array and an aperture array separated by a thin substrate. Simulation results prove that the resonant frequency of the two CFSSs could be tuned by rotating the patch elements. Such tunable property is explained by the electromagnetic interaction between the two complementary layers. Experimental results showed that both CFSS have good angular stability and their resonance could be tuned. Such tunable property provides a promising solution to the active FSS design.

Laser has several advantages, such as strong anti-interference ability, quick speed, high power, agility and precision. It is widely applied in military and medicine fields. When laser acts on human body, biological tissue of human body will appear the phenomenon of ablation and carbonization and solidification. In order to effectively defend excess damage by laser, the thermal effect research of skin tissue should be carried out. Temperature is a key parameter in the processing between laser and bio-tissue. It is the mostly foundation using analyze size of thermal damage area and forecast thermal damage degree. In this paper, the low fineness optical fiber F-P sensing system for temperature measurement is designed and established. The real-time measurement system of temperature generated by laser irradiating bio-tissue is build based on the sensing system. The temperature distributing generated by laser in the bio-tissue is studied through experiment when the spot diameter of emission laser is difference with the same energy density and the energy density is difference with the same spot diameter of emission laser. The experimental results show that the sensing system can be used to the real-time temperature measurement of bio-tissue efficiency. It has small bulk. Its outer diameter is 250μm. And the hurt for bio-tissue is small. It has high respond speed. The respond time of temperature is less than 1s. These can be satisfied with practice demand. When the energy density of laser is same, the temperature rising in the same location is low along the spot diameter of emission laser increasing. When the spot diameter of emission laser is same, the temperature rising in the same location is increasing along with the energy density of laser increasing.

Studied by dc reactive magnetron sputtering method, with Si - p and Si (111) - p (100), two different Si do base, affect the performance of TiNx thin film preparation. Results show that Si - of the preparation of p (111) as the basal TiNx film performance is better than that of Si - p (100), the performance in the particles more renew, more Octavia and XRD diffraction fengfeng shape with TiNx diffraction peak do not overlap. Therefore, choose p - Si (111) basal deposited titanium nitride thin films, can meet the requirements of the preparation of optical thin film quality.

In this paper, we present an analysis of transverse mode competition mechanism in multicore fiber lasers based on the transversally-resolved steady rate equations with consideration of transverse gain distribution and mode propagation loss. Based on the model, the output beam properties of 7-core and 19-core fiber lasers are simulated numerically when applying a plane reflection mirror and Talbot cavity as the feedback boundary conditions, respectively. We propose a new parameter of brightness factor to find out the best Talbot distance. We also give analysis on the influence of the fiber core separation distance and core diameter to the output laser beam quality. The study shows that the Talbot cavity can realize the mode selection of multicore fiber lasers and make the in-phase supermode dominate in the output beam, thus enhancing the quality of the output beam. The shorter the core separation distance and the core diameter are, the better the output beam quality would be. The best optimized core separation distance within acceptable beam quality restriction and the processing technic limit is obtained. This work has great prospective in the design and application of multicore fibers.

In this paper, Multi-walled carbon nanotubes (MWCNTs)-tin oxide (SnO₂) composites were selected as sensing materials to detect NO₂ with concentrations ranging from 10 ppm to 50 ppm. Two sensors with different mass fractions of SnO₂ and MWCNTs, i.e., 6.7% and 10%, were fabricated by airbrushing the composites on interdigitated electrodes (IDEs). Response performances of both sensors at room temperature were investigated. Results showed that the sensor with mass fraction of 10% exhibited a larger sensing response and a bigger sensitivity than the other one, and a good linearity was observed for both ones. In addition, both sensors had a good selectivity to NO₂ in comparison with the other five interfering gases.

In this paper, bottom contact organic thin film transistors (OTFTs) using SiO₂ dielectric layer deposited on silicon wafer were fabricated for gas sensors application. Single-walled carbon nanotubes (SWNTs)- polyethylenimine(PEI) bilayer sensitive film was utilized as an active layer to test current-voltage characteristics and gas-sensing properties of the OTFT device. Due to PEI coating, the electronic characteristic of the active layer was turned from p-type (SWNTs film) into n-type (SWNTs-PEI bilayer film). When the gas sensor was exposed to NO₂ of different concentrations at room temperature, the source-drain current changed within several minutes at appropriate gate and source-drain voltages. The selectivity and repeatability of gas sensor were investigated as well. The results showed that the gas sensor exhibited outstanding properties to NO₂ gas. Moreover, the gas sensing mechanism of the sensitive film associated with the morphology analyzed by scanning electron microscope (SEM) was studied.

Polyvinylpyrrolidone (PVP)/reduced graphene oxide (RGO) nanocomposites are sprayed on quartz crystal microbalance (QCM) for NO₂ sensing. The thin films are characterized by Fourier transform infrared spectroscopy (FTIR) and ultraviolet-visible spectroscopy (UV-VIS). The experimental results reveal that PVP/RGO sensor exhibits higher sensitivity and shorter recovery time than those of PVP. Besides, the response to 20 ppm NO₂ is higher than other gases such as CO, CO₂ and NH₃ even at 100ppm. When the PVP/RGO sensor is exposed to these gases, the good selectivity to NO₂ makes the sensor ideal for NO₂ detection.

Electron beam direct wring lithography has been an indispensable approach by which all sorts of novel nano-scale devices include many kinds optical devices can be fabricated. Alignment accuracy is a key factor especially to those devices which need multi-level lithography. In addition to electron beam lithography system itself the quality of alignment mark directly influences alignment accuracy. This paper introduces fundamental of alignment mark detection and discusses some techniques of alignment mark fabrication along with considerations for obtaining highly accurate alignment taking JBX5000LS and JBX6300FS e-beam lithography systems for example.
The fundamental of alignment mark detection is expounded first. Many kinds of factors which can impact on the quality of alignment mark are analyzed including mark materials, depth of mark groove and influence of multi-channel process. It has been proved from experiments that material used as metal mark with higher average atomic number is better beneficial for getting high alignment accuracy. Depth of mark groove is required to 1.5～5 μm on our experience. The more process steps alignment mark must pass through, the more probability of being damaged there will be. So the compatibility of alignment mark fabrication with the whole device process and the protection of alignment mark are both need to be considered in advance.

For the benefit of electrical isolation, corrosion resistance and quasi-distributed detecting, Fiber Bragg Grating Sensor has been studied for high-speed railway application progressively. Existing Axle counter system based on fiber Bragg grating sensor isn’t appropriate for high-speed railway for the shortcoming of emplacement of fiber Bragg grating sensor, low Sampling rate and un-optimized algorithm for peak searching. We propose a new design for the Axle counter of high-speed railway based on high-speed fiber Bragg grating demodulating system. We also optimized algorithm for peak searching by synthesizing the three sensor data, bringing forward the time axle, Gaussian fitting and Finite Element Analysis. The feasibility was verified by field experiment.

As the Photoelectric tracking system develops from earth based platform to all kinds of moving platform such as plane based, ship based, car based, satellite based and missile based, the fault tolerance control system of phase current sensor is studied in order to detect and control of failure of phase current sensor on a moving platform. By using a DC-link current sensor and the switching state of the corresponding SVPWM inverter, the failure detection and fault control of three phase current sensor is achieved. Under such conditions as one failure, two failures and three failures, fault tolerance is able to be controlled. The reason why under the method, there exists error between fault tolerance control and actual phase current, is analyzed, and solution to weaken the error is provided. The experiment based on permanent magnet synchronous motor system is conducted, and the method is proven to be capable of detecting the failure of phase current sensor effectively and precisely, and controlling the fault tolerance simultaneously. With this method, even though all the three phase current sensors malfunction, the moving platform can still work by reconstructing the phase current of the motor.

Hydrogen-bond acidic (HBA) polymers are widely used for the detection of dimethyl methyl phosphonate (DMMP, a simulant of real nerve agents) based on surface acoustic wave (SAW) sensors. This paper presented an HBA polymer PLF, and subsequently the polymer was dissolved into chloroform and spray-coated on a SAW device to fabricate a gas sensor. Then the sensor was equipped into a SAW test platform to investigate its sensitive property to soman vapor and its simulant DMMP at the concentrations below 20 mg/m³. Results revealed that the sensor showed high sensitivity to the analyte vapors, furthermore, the response of the sensor to soman vapor was relatively smaller and slower than that to DMMP. Tests to some common interference vapors were studied at the concentration of 10 mg/m³, and the results indicated that the sensor showed a good selective property.

As one of the main factors of restricting the fiber Bragg grating based Fabry–Perot (FBG-based F-P) sensitivity enhancement system, the intensity will be more and more unbalanced and weakened following the improvement of sensitivity enhancing ability. In this paper, intensity unbalance of the pulse train is analyzed. A secondary wave chopping, amplifying and filtering modified scheme is proposed to solve it. A four centimeters diameter compliant cylinder fiber optic accelerometer is fabricated. An experiment is set to validate the improved system. The phase sensitivity calibration results are consistent with the theory well and truly by phase-generated carrier (PGC) scheme. This system achieves 20 times (26 dB) sensitivity enhancement and 10 dB noise floor improvement at the same time successfully.

To solve the problem of a large amount of invalid sample and accumulations yielded by random sampling when randomized hough transform (RHT) is used to detect circles in complex images processing, an new improved arithmetic for circle detection is developed in this paper. It not only uses gradient direction information to determine whether the three sampling points should be accumulated or not, but also uses the regular hexagon window to narrow the searching range of pixels to improve the operating speed. The problem of invalid sampling and accumulations and multi-circle detection is well solved. The experiment results show that this algorithm has higher speed, smaller storage and better detection performance.

Chiral plasmonic structures provide an effective way to couple optical spin with orbital angular momentum, which is suitable to perform manipulation of light beam. This work presents simulation results for a type of spiral-ring plasmonic structures that provide circular polarization selectively in the visible spectrum. The structure consists of discrete spiral gratings that are truncated by rings. With circular polarized lights transmitting the subwavelength structure, surface plasmon polaritons and localized surface plasmons are excited together. Thus, multi-rings spiral plasmonic structures are introduced to obtain high extinction ratio circular dichroism. Moreover, the wavefront phase singularity is also observed in the simulation.