Manuel Collet

Enhanced electro-optical lithium niobate photonic crystal wire waveguide on a smart-cut thin film.

We report an electro-optically tunable photonic crystal linear cavity etched on a 200 nm lithium niobate waveguide ridge. The photonic crystal cavity and the ridge are both fabricated on a 1 μm thin film of lithium niobate obtained by smart-cut technology. The photonic crystal, of area 4x0.8 μm2, has been engineered to work in a slow light configuration so that the electro-optic effect is 20 times more important than in bulk material.

Analysis of the behavior of a Shape Memory Alloy beam under dynamical loading

Abstract Shape Memory Alloys (SMAs) are widely studied as new materials with potential for use in various passive or active vibration isolation systems. Up to now, few papers deal with a precise description of their proper dynamic behaviour. However, it is important to clearly understand the dissipation mechanisms in order to optimize the design of a structure. We present here a detailed characterization of a Cu–Al–Be beam. The stress induced phase transformation austenite → martensite produces a strongly nonlinear behaviour. The aim of this study is to confront experimental results to a rheological model of the beam. The experimental setup consists in a cantilever beam excited by a light electromagnetic actuator. The response is measured by an accelerometer fixed at the free end of the beam. Stepped sine measurements have been performed around the frequency of the first mode of the beam under different excitation levels. The obtained frequency response functions strongly depend on the global vibration amplitude. Then a specific finite element model has been designed, taking into account the geographic repartition of the two phases inside the beam. The simulations show a similar behaviour and allow the interpretation of the experimental observations.

Integrated temperature sensor based on an enhanced pyroelectric photonic crystal

In this paper, temperature variations are detected thanks to an enhanced nano-optical pyroelectric sensor. Sensing is obtained with the pyroelectric effect of lithium niobate (LN) in which, a suitable air-membrane photonic crystal cavity has been fabricated. The wavelength position of the cavity mode is tuned 11.5 nm for a temperature variation of only 32 °C. These results agree quite well with 3D-FDTD simulations that predict tunability of 12.5 nm for 32 °C. This photonic crystal temperature sensor shows a sensitivity of 0.359 nm/°C for an active length of only ~5.2 μm.

6-micron interaction length electro-optic modulation based on lithium niobate photonic crystal cavity

We report on electro-optic modulation using a Lithium Niobate (LN) Photonic Crystal (PC) cavity structure. The compact device (6 μm in length) consists of a 2D photonic crystal cavity made on an Annealed Proton Exchange (APE) LN waveguide with vertical deposited electrodes. Experimental results show a tunability of 0.6 nm/V. This compact design opens a way towards micro and nano-scale tunable photonic devices with low driving electrical power.

Lithium niobate photonic crystal wire cavity: Realization of a compact electro-optically tunable filter

We report an electro-optically tunable filter using a lithium niobate photonic crystalcavity configuration with an efficient optical guiding geometry. The compact device (5.5 μm × 2.8 μm) was made on a hybrid waveguide combining an annealed proton exchange waveguide and a ridge waveguide realized by focused ion beam with vertically deposited electrodes. Due to the slow light and nonlinear effect in lithium niobate photonic crystal, experimental results show an enhanced tunability of ∼0.56 nm/V. This compact tunable photonic crystalcavity demonstration opens the path for the development of micro and nano-scale low-power driving active photonic devices.