we propose a new ring resonator side-coupled m-z interferometer all-optical switch throughthe pumped nonlinear directional coupler. by controlling pump power p to lead the coupler reflectivityr approaching to 1, the resonator finesse will be enhanced dramatically, and then the minimumswitching power in silica-based practice devices can be obtained. as a sample, we use a nonlinearcoupler made by...

This paper presents two key technology components required for the development of a self-powered, wireless, active acoustic liner system. The envisioned system consists of a tunable Helmholtz resonator for acoustic impedance boundary condition modification and an acoustic energy reclamation module as a system power supply. The common electroacoustic element for both of these components is an el...

One of the main noise sources in computers are the cooling fans. Tonal noise at the rotational frequency of the fan, the blade passing frequency (BPF) and its higher harmonics are important in fan noise. So called 'side-resonators' integrated in the duct of an in-duct axial fan cause an impedance change in the duct and, having proper dimensions and correct position, act as an acoustic mirror re...

The acoustic characteristics of a hybrid silencer consisting of two dissipative chambers and a Helmholtz resonator are investigated first computationally and experimentally. Complex wave number and characteristic impedance are used for the dissipative chambers to account for the wave propagation through absorbing material. Three-dimensional boundary element method (BEM) is employed to predict t...

abstract background: given the fact of irrecoverable consequences of noise in industrial societies and the environment, acoustic filter (silencer) is an instrument which obstacles the transmission of sound waves. a sort of this silencer is helmholtz resonator (branch amplifier) which comes to sound appropriate for low and below 200 hz frequencies in fan and channel noise. the purpose of this ar...

This study investigates the acoustic performance of a system two Helmholtz resonators experimentally and numerically. The distance between was varied to assess its effect on quantitatively. Experiments were performed using an impedance tube with instrumented several microphones along tube. relation noise attenuation is presented in terms transmission loss, coefficient, change sound pressure lev...

In this paper, using annular resonator we have designed an adding and dropping filter light based ontwo-dimensional photonic crystals. The shape of ring resonator filter adding and dropping that wehave proposed is Race Track. This filter has a hexagonal lattice structure of silicon bars withrefractive index 3/46 that is located in the context of air with refractive index 1. Transmissionefficien...

This research quantitatively investigates fluid damping of MEMS and NEMS flexural resonators such as scanning probe and carbon nano-tube resonators, aiming to improve the quality factor prediction and therefore the resonator design. Fluid damping in beam-type resonators is most affected by resonant frequency, device dimensions and cross-sectional shape which are systematically examined within. ...

The design and operation of a proof-of-principle rectangular He-Ne ring laser resonator with a cavity perimeter of 77.0 m and an area of approximately 367 m2 are described. With unevacuated beam lines this device gave an Earth-induced Sagnac frequency of 1513 Hz, with a relative Allan deviation over 1000 s down to 3 parts per million. The Earth's rotation provided a bias that eliminated the loc...