Monolithic integration of a silica-based 16-channel VMUX/VDMUX on quartz substrate

A monolithic integrated variable attenuator multiplexer/demultiplexer is demonstrated. It is composed of a 16-channel 200 GHz silica-based arrayed waveguide grating and an array of Mach-Zehnder interferometer thermo-optic variable optical attenuators. The integrated device is fabricated on a quartz substrate, which eliminates the process of depositing the undercladding layer and reduces the power consumption compared with a device fabricated on a silicon substrate. The insertion loss and crosstalk of the integrated device are -5 dB and less than -22 dB, respectively. The power consumption is only 110 mW at the attenuation of 20 dB per channel.

Surface roughness of optical quartz substrate by chemical mechanical polishing

In order to achieve a high-quality quartz glass substrate and to improve the performance of TiO2 antireflection coating, chemical mechanical polishing （CMP） method was used. During CMP process, some process parameters including pressure, polishing head speed, platen speed, slurry flow rate, polishing time, and slurry temperature were optimized to obtain lower quartz surface roughness. According to the experiment results, when pressure was 0.75 psi, polishing head speed was 65 rpm, platen speed was 60 rpm, slurry flow rate 150 mL/min, slurry temperature 20℃, and polishing time was 60 s, the material removal rate （MRR） was 56.8 nm/min and the surface roughness （Ra） was 1.93 A （the scanned area was 10 × 10 μm^2）. These results were suitable for the industrial production requirements.

Growth of Serpentine Carbon Nanotubes on Quartz Substrates and Their Electrical Properties

A simple method for high-yield,chemical vapor deposition(CVD)synthesis of serpentine carbon nanotubes,employing quartz substrates and a molecular cluster catalyst,is described.The growth mechanism is analyzed by controlled addition of nanoscale barriers,and by mechanical analysis of the curved sections.The serpentine structures are used to study the electrical transport properties of parallel arrays of identical nanotubes,which show three-terminal conductance that scales linearly with the number of nanotube segments.

Longitudinal leaky surface acoustic wave on Y-rotated cut quartz substrates

The properties of Quasi-longitudinal leaky surface acoustic wave(QLLSAW) on Y-rotated cut quartz substrates were presented. The phase velocity of QLLSAW on the quartz substrate along some orientations can be up from 6200 m/s to 7100 m/s, circa 100% above that of regular SAW. Both theoretical and experimental results show that QLLSAW propagating along some promising orientations for SAW devices are of small power flow angle and low tem-perature coefficient, for example, along the Euler angle (0°155.25°? 42°?, the measurements of phase velocity and temperature coefficient of delay of QLLSAW are 6201 m/s and 12.9 ppm/℃. The experimental results show that QLLSAW had little absorption by liquid loading on the substrate surface, which proved that the direction of particle motion is the same as wave vector and parallel to the surface of the substrates, i.e., the wave is of the properties of longitudinal wave.

Sputter Deposited Carbon Material based Fabry-Perot Sensor and Downhole Application

To prevent hydrogen-induced loss and achieve long-term effective parameters monitoring in harsh downhole environment,we proposed a Fabry-Perot sensor with vacuum sputter deposited carbon coating film,in which we employed a deposition technology with a higher particle kinetic energy,closer substrate adhesion,and denser films,to deposit the coating film on the surface of the quartz capillary glass tube to protect the sensor from corrosion.The sensitivity and accuracy of the Fabry-Perot sensor with carbon film deposition can reach 369 nm/MPa and 0.02%FS,respectively.Meanwhile,the sensor has less hysteresis error and good pressure linearity of more than 0.99999 for repeatable pressure measurement.The downhole practice monitoring data indicated that this fiber-optic sensor exhibited excellent performance and the sputter deposited carbon coating can effectively decrease hydrogen loss.

Research on conductive-material-filled electrodes for sidewall insulation performance in micro electrochemical machining

In micro electrochemical machining(ECM)processes,stray corrosion causes undesired metal dissolution and the deterioration of shape accuracy.Adopting a sidewall-insulated electrode is an effective approach to suppressing stray corrosion.Most sidewall-insulated electrodes are made of metal substrate and non-metallic thin films.Nevertheless,the thin-film insulating materials attached to a metal substrate are susceptible to damage in an electrolytic environment.This study presents a novel concept of the conductive-material-filled electrode for better sidewallinsulation performance.The micro-scale quartz tube serves as the insulating substrate.Commercially available conductive fillers including metal wire,molten metals,and silver powder are filled inside the working cathode of the quartz tube.Consequently,the metal-wire-filled electrode,moltenmetal-filled electrode,and nano-powder-filled electrode are designed and fabricated.From the verification results of electrode toughness,material removal rate,and surface topography,the metal-wire-filled electrode and moltenmetal-filled electrode exhibit the same performance as a traditional metal-based electrode and much better durability.By contrast,the nano-powder-filled electrode is unable to withstand long-term ECM processes because of the loss of cured powder particles.In ECM experiments,microstructures with steep sidewalls(taper angle<9.7°)were machined using the metal-wire-filled electrode and molten-metal-filled electrode,which could replace the traditional electrode,achieving a longer service life and superior sidewall-insulation performance.