Tunable Porous Silicon Mirrors for Optoelectronic Applications
- PDF / 142,764 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 25 Downloads / 217 Views
F3.50.1
Tunable Porous Silicon Mirrors for Optoelectronic Applications Sharon M. Weissa, Mikhail Haurylaub, and Philippe M. Faucheta,b a Institute of Optics, University of Rochester, Rochester NY 14627, USA b Department of Electrical and Computer Engineering, University of Rochester, Rochester NY 14627, USA
ABSTRACT Tunable porous silicon mirrors were fabricated as building blocks for optical interconnects and as a first step towards efficient routing of information on a small size scale. The basic structures for the tunable mirrors are porous silicon microcavities infiltrated with liquid crystals. The optical properties of the mirrors are influenced by thermal or electric field modulation. When the device is heated or a voltage is applied, the orientation of the liquid crystals changes, causing a change in the effective refractive index of the liquid crystals within the mirror. The position of the reflectance resonance of the porous silicon microcavity is particularly sensitive to such changes in the refractive index. A reversible 10nm shift of the reflectance resonance of the mirror, leading to a 30% change in the amplitude of reflectance, has been observed due to thermal effects. Not only do these results show potential for future devices, but they also confirm that the liquid crystals are able to rotate in the constricted geometry of the porous silicon microcavities. For voltage driven devices, careful attention needs to be given to the configuration of the electrical contacts. The effectiveness of various device geometries has been investigated. Using standard lithographic techniques, aluminum contacts with minimum feature sizes of 10 microns were patterned directly on the porous silicon surface. A study on the use of free-standing porous silicon films was also performed.
INTRODUCTION The need to develop optical interconnects as part of the next generation of semiconductor technology has been established [1]. Interconnects create bottlenecks, slowing down the rate of data transfer from board to board, from chip to chip, and within a single chip. Silicon-based optical interconnects offer the possibility to use photons rather than electrons to transfer information on a platform that is compatible with the semiconductor technology used to fabricate microelectronic components. In this way, the speed of data transfer is increased and power dissipation is minimized. Silicon-based optical interconnects also have the potential to serve as essential components in integrated photonic circuits [2]. Passive silicon-based optical components such as mirrors and waveguides are well established [3,4]. Active (tunable) silicon-based components add an extra degree of freedom for data manipulation. The optical signal can be redirected on demand over a specified range of wavelengths. Liquid crystals have been chosen to facilitate the tunability of two-dimensional macroporous silicon photonic bandgap structures and self-assembled polymer inverse opals [5,6]. When the liquid crystals are heated above their phase transition temper
Data Loading...
