Rayleigh backscattering, optical fiber, optical time reflectometry, OTDR, white light interferometry, optical lowcoherence reflectometry Rayleigh backscattering at a wavelength of 1.55 um is measured in standard single-mode fiber with a spatial resol ution of 32 um and a dynamic range of over 30 dB. A minimum reflection sensitivity of -148 dB is the best reported to date using optical low-coher...

MATERIALS AND METHODS Combined QCM-D and reflectometry measurements. Combined QCM-D and reflectometry measurements were performed in flow mode using a prototype instrument.1 Gold-coated QCM-D sensor crystals (Q-Sense AB, Sweden) were modified to meet the requirement for sensitive reflectometry measurements by deposition of a 100 nm layer of Ti followed by a 110 nm layer of SiO2 onto the sensor ...

Simple expressions allowing estimation of the turbulent density perturbation from the reflectometry phase root mean square (r.m.s.) measurements and accounting for the turbulence correlation length are given. The numerical procedure for precise turbulence radial profile reconstruction for different turbulence wave number spectra and both O-mode and X-mode reflectometry is proposed. It is valida...

Plasma poloidal curvature can significantly extend microwave reflectometry responses to high k⊥ poloidal fluctuations. Reflectometry responses can be several orders of magnitude larger at high k⊥ than that predicted by analysis based on two dimensional (2-D) slab geometry. As a result, the responses may approach the 1-D geometrical optics limit. This super resolution leads to a major modificati...

A 2D finite-differences time-domain full-wave code is used to simulate the measurements of plasma filaments with fixed frequency O-mode reflectometry. The plasma is modeled by a linear slab plasma plus a Gaussian perturbation propagating in a direction that can vary from poloidal to radial. The plasma background density gradient is chosen in agreement with the steep edge transport barrier of H-...