International audienceThe effect of external optical feedback on an InAs/GaAs quantum dot passively mode-locked laser is investigated. The rf linewidth narrows from 8 KHz in the free-running situation to a value as low as 350 Hz under relatively low feedback. The rf linewidth characterization under resonant feedback at a multiple of the laser cavity length validates the prediction of a previous numerical simulation. It is also confirmed that the integrated rms timing jitter varies as the square root of the rf linewidth. The results are promising for the development of compact, monolithic semiconductor mode-locked lasers as low noise optoelectronic oscillators

This study presents a novel system architecture to implement silicon-on-glass (SOG) MEMS devices on Si-glass compound substrate with embedded silicon vias. Thus, the 3D integration of MEMS devices can be accomplished by means of through-wafer silicon vias. The silicon vias connecting to the pads of devices are embedded inside the Pyrex glass. Parasitic capacitance for both vias and microstructures is decreased and mismatch of coefficient of thermal expansion (CTE) is reduced. In applications, the glass reflow process together with the SOG micromachining processes were employed to implement the presented concept. Successful driving of the resonator through the silicon vias is demonstrated. The wafer-level hermetic packaging can be further achieved by anodic bonding of a Pyrex7740 wafer. Hermeticity of the packaged device performed by helium leak test satisfied MIL-STD-883E. The packaged SOG device is SMT (surface mount technology) compatible and ready for 3D microsystem integration.

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Packaging is an emerging technology for microsystem integration. The silicon-on-insulator (SOI) wafer has been extensively employed for micromachined devices for its reliable fabrication steps and robust structures. This research reports a packaging approach for silicon-oninsulator-micro-electro-mechanical system (SOI-MEMS) devices using through-wafer vias and anodic bonding technologies. Through-wafer vias are embedded inside the SOI wafers, and are realized using laser drilling and electroplating. These vias provide electrical signal paths to the MEMS device, while isolating MEMS devices from the outer environment. A high-strength hermetic sealing is then achieved after anodic bonding of the through-wafer-vias-embedded SOI wafer to a Pyrex 7740 glass. Moreover, the packaged SOI-MEMS chip is compatible with surface mount technology, and provides a superior way for 3D heterogeneous integration.

International audienceDynamic feedback properties of a 1.55 μm InAs/InP quantum dash laser are reported. The ground state linewidth enhancement factor (αH-factor) is found to be enhanced from ∼ 1 to ∼ 14 as the bias current is increased beyond the threshold value. As a consequence of the variation in the αH-factor, the feedback sensitivity of the quantum dash semiconductor laser is dramatically affected over the entire range of operational currents. The onset of its critical feedback regime, which is incompatible with data transmission, is shown to exhibit a variation of approximately 20 dB for the quantum dash device