1.3 μm quantum-dot electro-absorption modulator

The electro-absorption properties and Stark-shift of 1.3μm InGaAs quantum dot waveguide modulators are characterized under reverse bias. 2.5Gb/s data modulation is demonstrated for the first time with clear eye diagrams and error-free back-to-back performance. © 2007 Optical Society of America.

Optimization of efficiency-loss figure of merit in carrier-depletion silicon Mach-Zehnder optical modulator.

In this paper we study the optimization of interleaved Mach-Zehnder silicon carrier depletion electro-optic modulator. Following the simulation results we demonstrate a phase shifter with the lowest figure of merit (modulation efficiency multiplied by the loss per unit length) 6.7 V-dB. This result was achieved by reducing the junction width to 200 nm along the phase-shifter and optimizing the doping levels of the PN junction for operation in nearly fully depleted mode. The demonstrated low FOM is the result of both low V(π)L of ~0.78 Vcm (at reverse bias of 1V), and low free carrier loss (~6.6 dB/cm for zero bias). Our simulation results indicate that additional improvement in performance may be achieved by further reducing the junction width followed by increasing the doping levels.

Efficient InGaAsP/InP multiple quantum well optical phase modulator for the 1.5-1.55μm fiber band

We report an InGaAsP/InP MQW phase modulator operating over the entire 1.55μm fiber band with high phase modulation efficiency and low loss modulation. The spectral dependence of the electro-refraction in a MQW structure is measured for the first time.

Electro-optic modulation of 1.5μm light in an active InGaAsP/InP quantum well waveguide

We report an InGaAsP/InP phase modulator operating in the 1.5μm wavelength band. Phase modulation of 7.5°/mA and 1.7°/mA of injected current have been measured for TE and TM polarised light respectively at a signal wavelength of 1.52 μm.

Digital data transmission using electro-optically modulated vertical-cavity surface-emitting laser with saturable absorber

An electro-optically (EO) modulated oxide-confined vertical-cavity surface-emitting laser (VCSEL) containing a saturable absorber in the VCSEL cavity is studied. The device contains an EO modulator section that is resonant with the VCSEL cavity. A type-II EO superlattice medium is employed in the modulator section and shown to result in a strong negative EO effect in weak electric fields. Applying the reverse bias voltages to the EO section allows triggering of short pulses in the device. Digital data transmission (return-to-zero pseudo-random bit sequence, 27-1) at 10Gb/s at bit-error-rates well below 10-9 is demonstrated. © 2014 AIP Publishing LLC.

The plastic collapse and energy absorption capacity of egg-box panels

The plastic collapse response of aluminium egg-box panels subjected to out-of-plane compression has been measured and modelled. It is observed that the collapse strength and energy absorption are sensitive to the level of in-plane constraint, with collapse dictated either by plastic buckling or by a travelling plastic knuckle mechanism. Drop weight tests have been performed at speeds of up to 6 m s-1, and an elevation in strength with impact velocity is noted. A 3D finite element shell model is needed in order to reproduce the observed behaviours. Additional calculations using an axisymmetric finite element model give the correct collapse modes but are less accurate than the more sophisticated 3D model. The finite element simulations suggest that the observed velocity dependence of strength is primarily due to strain-rate sensitivity of the aluminium sheet, with material inertia playing a negligible role. Finally, it is shown that the energy absorption capacity of the egg-box material is comparable to that of metallic foams. © 2003 Elsevier Ltd. All rights reserved.

3D thermo-electro-mechanical simulations of gas sensors based on SOI membranes

3D thermo-electro-mechanical device simulations are presented of a novel fully CMOS-compatible MOSFET gas sensor operating in a SOI membrane. A comprehensive stress analysis of a Si-SiO2-based multilayer membrane has been performed to ensure a high degree of mechanical reliability at a high operating temperature (e.g. up to 400°C). Moreover, optimisation of the layout dimensions of the SOI membrane, in particular the aspect ratio between the membrane length and membrane thickness, has been carried out to find the best trade-off between minimal device power consumption and acceptable mechanical stress.