Vertical mirrors fabricated by reactive ion etching for fiber optical switching applications

MOEMS tuning element for a Littrow external cavity laser

“…The width of all flexures was 6 , and the width of the strut linking the portal beams was 18 . The beams in the portal frame were spaced apart by a distance of 50…”

“…The actuator is fabricated by deep-reactive ion etching (DRIE) [16] of bonded silicon-on-insulator (BSOI). DRIE of BSOI yields devices with a high aspect ratio and out-of-plane stiffness [17] and high quality optical surfaces, such as mirror insertion switches [18]. In earlier work, we have shown that DRIE may also be used to form blazed gratings (albeit with limited resolution) [19].…”

Micromachining for optical and optoelectronic systems

“…Though the etched surface is rougher than the wet chemically etched (110) wafer, it is still smooth enough for many micromirror applications. Marxer et al [13] and Juan et al [14] have used the DRIE technique to fabricate a vertical micromirror for fiber-optic switches. The microactuators for the switch are also integrated through the same DRIE process.…”

“…The microactuators for the switch are also integrated through the same DRIE process. The mirror roughness is estimated to be 36 nm, which corresponds to a scattering loss of 6% [13].…”

“…One potential issue for such microlenses is the scattering loss of the supporting polysilicon plate. The scattering loss is related to the surface roughness by [13], [40] where is the percentage of the scattering loss, is the root-mean-square roughness of the polysilicon surface, is the incident angle, and is the optical wavelength. The surface roughness of as-grown polysilicon is on the order of 45 nm (the exact value depends on the deposition condition), and the corresponding scattering loss is 17% per interface at 1300-nm wavelength.…”