Widely tunable Fabry-Perot filters using high-index-contrast DBRs

Realization of microelectromechanically wavelength tunable Fabry-Perot filters using high index-contrast distributed Bragg reflectors (DBRs) comprising GaAlAs/AlOx and Si/SiO2 material system are reported. Due to the broadband nature of these high index-contrast DBRs, the 3dB transmission bandwidth of the cavity resonance is narrow and stable over the tuning range. While the three different sets of GaAlAs/AlOx based filters with different number of DBRs exhibited linewidths of 0.5nm, 2.0nm and 0.47nm with tuning ranges of 59nm, 83nm, and 60nm respectively, the silicon-based filter exhibited a linewidth of 0.3nm and a tuning range of 12nm. Transmission spectra from these devices displayed varying magnitudes of higher order spatial modes were attributed to lensing effect caused by partially oxidized AlGaAs layers within the mirror layers. One of the GaAlAs filters showed a frequency response of 500 KHz at 3dB cutoff point indicating a switching time of 2 microseconds.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.