Integrated Circuit Platform Research Articles

High efficiency widely tunable SGDBR lasers for improved direct modulation performance

We report on two novel approaches to improve the differential quantum efficiency (DQE) of widely tunable 1.55-/spl mu/m lasers: the bipolar cascade sampled grating distributed Bragg reflector (BC-SGDBR) laser and the gain-levered SGDBR (GL-SGDBR) laser. Each is fabricated on a robust InGaAsP/InP photonic integrated circuit platform. The lasers demonstrate improved direct modulation performance over conventional SGDBR lasers. The BC-SGDBR laser was also monolithically integrated with a semiconductor optical amplifier and photodetector receiver in order to perform wavelength conversion. Error free wavelength conversion at 2.5 Gb/s and improvements in conversion efficiency are demonstrated.

Synthesis of Nanoscale Devices for Neural Electrophysiological Imaging

AbstractA device with nanometric resolution in space and millisecond resolution in time, intended for neural electrophysiological imaging applications, is being developed and fabricated for in vitro experimentation. The device consists of (i) an integrated circuit (IC) platform and (ii) a carbon nanotube/polymethylmethacrylate composite construct. Arrays of equi-spaced multiple gold electrodes were fabricated using combined e-beam and optical lithography to achieve three types of IC platforms with three different scales of resolution. Carbon nanotubes were synthesized on silicon dioxide substrates using a chemical vapor deposition method. Subsequently, the carbon nanotube arrays were infiltrated with in situ polymerized polymethylmethacrylate to achieve electrical insulation between adjacent nanotube bundles. The composite construct was fabricated and exhibited electrical conductivity and connectivity between two faces of the composite along the length of the nanotubes. The carbon nanotube arrays grown on silicon dioxide exhibited uniform length and a high level of alignment, which was preserved subsequent the in situ polymerization process. The devices can be deployed as an interface between ICs and mammalian cells.