High quality factor Er-doped Fabry–Perot microcavities by sol–gel processing

Abstract

An optimized sol–gel process was developed to fabricate 1D photonic bandgap structures. Several erbium-doped Fabry–Perot microcavities were prepared and characterized. The thickest sample contained two Bragg mirrors, each having 12 distributed Bragg reflector periods of alternating silicate glass and titania layers. The total thickness of this sample reached ∼12 µm. The Er3+ photoluminescence spectra at 1.5 µm were measured for the microcavities. A quality factor of 250 and an Er3+ photoluminescence enhancement of 96 times at 1.5 µm have been reached. The sol–gel processing details, the crystallization of the titania films and the refractive index of the deposited materials are discussed in detail. The simulated optical spectra of the microcavities were found to agree well with the actually measured curves. These results demonstrate that the present sol–gel processing technique is of potential interest for low cost fabrication of 1D photonic bandgap devices.