Passive DWDM components using MicroPlasma optical interference filters

Summary form only given. Thin-film resonant cavity filters have been incorporated into passive wavelength-division multiplexing (WDM) components by a number of vendors. However, when conventional filter technology has been applied to narrow-band DWDM applications, several shortcomings become evident, such as poor temperature and environmental stability, high insertion loss, or poor bandpass spectral shape. Typically, these problems can be traced primarily to defects with film morphology such as: porosity, scatter, absorption, columnar structure, inhomogeneity, or lack of accurate thickness control. OCA has developed a technology to deposit ultranarrow band resonant cavity interference filters, which solves the performance problems associated with conventional thin films. The technique, which goes by the trade name MicroPlasma, is an energetic high vacuum physical vapor deposition (PVD) process, which uses refractory metal-oxide coating materials such as silicon dioxide and tantalum pentoxide.