III-V semiconductor material for tunable Fabry-Perot filters for coarse and dense WDM systems

In the following payer, we report on the investigation of the mechanical pr operties of InP grown on InGaAs by organic metal vapor phase epitaxy (OMVPE ). When InP is grown, it is stressed due to an unintentional arsenic doping profile. This stress gradient was compensated using an interfacial InGaP l ayer. To enable more flexible structures, optimization of growth conditions for InP on InGaAs enabled the thickness of released InP beams to be signif icantly reduced compared to previous works. Tunable Fabry-Perot filters hav e been processed to demonstrate the mechanical properties of the grown mate rial for the use in micro-opto-electro-mechanical systems (MOEMS). The devi ces are fabricated by surface micromachining, utilizing a selective removal of a sacrificial InGaAs layer and thus creating a tunable air gap cavity. The passband of the non-tuned device is centered at lambda = 1550 nm. The c oarse filter has a FWHM of 10 nm while the filter for dense WDM systems is designed to have a FWHM of less than 1 nm. For the coarse filter, a tuning of the resonance peak over 45 nm is achieved by capacitive actuation. The t ransmission spectra of the dense WDM filter could not be measured due to hi gh absorption in the amorphous silicon layers in the top mirror. (C) 2000 E lsevier Science S.A. All rights reserved.