(Image: Kyocera Corp.)
Kyoto, Japan--Kyocera Corporation (NYSE:KYO)(TOKYO:6971) says that it has developed an etalon filter for use in wavelength-division multiplexing (WDM) with a wavelength-measuring capability that is independent of temperature (0 +/- 0.15 pm/°C). The filters, developed at Kyocera's wholly owned subsidiary Kyocera Crystal Device Corporation, are manufactured using atomic-diffusion bonding -- an industry first, says Kyocera.
Other bonding techniques include optical contacting, which creates a nice zero-thickness bond but is not very high in strength, and adhesive bonding, which is stronger but introduces the problem of a variable bonding thickness. The atomic-diffusion bonding technique used at Kyocera was developed by Takehito Shimatsu, a professor at Tohoku University (Sendai, Japan). It is very strong and has zero thickness.
The etalon filter itself is 1.2 mm square, has a free spectral range (FSR) of either 50 or 100 GHz, and is designed for the 1520 to 1620 nm wavelength range. The temperature-insensitive design of the filter means that it requires no Peltier thermoelectric devices for temperature stabilization.
Kyocera notes that its Crystal Device division has an integrated production setup in which all processes from cultivation of crystal materials to design, processing, coating, and characteristics evaluation are all done internally.
Samples of the filter will be available starting January 2013.