Shin-Etsu Chemical Develops New Optical Component Material for Optical Communications Parts

23-Jan-2007

Shin-Etsu Chemical Co., Ltd. announced that it has developed a manufacturing technology for lead-free optical isolators, which enables it to comply with the European RoHS Directive (Restriction of Hazardous Substances). Until now, Faraday rotators, which are main component parts of optical isolators, contained lead; however, this newly developed technology has made it possible to totally eliminate the lead element in optical isolators.

According to the company, the technology that Shin-Etsu has expeditiously developed fulfills the equipment makers' expectation by achieving the total elimination of lead from optical isolators. Going forward, this new technology shall enable the optical communications industry to comply with the expanding scopeof environmental regulations.

Optical isolators are set in such devices as laser modules. Such isolators permit optical light that is emitted by a laser diode to be transmitted in only one direction. They are used to protect laser diodes because they block the adverse effect of return beams that go back to the laser diodes from the optical fiber transmission channels and amplifiers.

Rare-earth iron garnet single crystals with a thickness of several hundred microns, which are grown by the Liquid Phase Epitaxy (LPE) method, are used in Faraday rotators for optical isolators. In the LPE method, an oxide flux is used to melt the crystal component at a lower melting point. Until now, lead oxide was considered to be an essential material, and for this purpose, the rare-earth iron garnet single crystals contained about 5,000 ppm of lead oxide.

Shin-Etsu Chemical, by developing its own original LPE method that does not use lead oxide at all, succeeded in developing for the first time in the world the technology to grow rare-earth iron garnet crystals with a thickness of several hundred microns and reduce to zero ppm the amount of lead in Faraday rotators, which are a key component part of optical isolators.

https://www.chemeurope.com/en/news/61107/shin-etsu-chemical-develops-new-optical-component-material-for-optical-communications-parts.html