In this Letter, we report a single-ended distributed vibration sensor with the 100 km sensing range. This sensing range is achieved by remotely pumping two pieces of Er-doped fibers incorporated along the sensing fiber with a 1480 nm Raman fiber laser at the front end. A strain resolution of 100 nϵ combined with a spatial resolution of 2.6 m is achieved at the far end of the fiber.

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100-km-sensing-range single-ended distributed vibration sensor based on remotely pumped Erbium-doped fiber amplifier.

A highly efficient Y-junction based on a planar photonic crystal (PhC) platform is presented. The PhC consists of a triangular array of holes etched into GaAs/AlGaAs heterostructure. The Y-junction has smaller holes positioned at the center of the junction, giving rise to very uniform splitting and high transmission. The performance is very encouraging, with simulation transmission of approximately 50% for each arm of the Y-splitter relative to a comparable single-defect PhC waveguide.

Improved transmission for photonic crystal Y-junctions

In this paper, the authors present a continuous membrane deformable mirror array based on silicon-on-insulator (SOI) bulk micromachining technology for applications in adaptive optics. In order to facilitate the use of the device layers of SOI wafers for the reflective surface and electrostatic actuators, the fabrication of the micromirror array is separated from the electronics chip, and then they are bonded together using the flip-chip assembly. The optical reflective membrane formed by the device layer of one SOI wafer is of high quality in terms of flatness and surface roughness; the stroke space is mainly determined by the height of the device layer of another wafer. The simulation results of the actuator performance by the finite element analysis method shows that the stroke is up to 2μm at about 70V actuation voltage and the frequency is about 17.8kHz.

T. Ohsaki

Papers

Introduction to the Special Section on Micro-Opto-Electro-Mechanical Systems