New micromachined VOA for improvement of the optical characteristics

Abstract

New micro-machined VOA (Variable Optical Attenuator) is proposed, which has a micro shutter coated with light dissipative material such as Ti. A couple of tapered fibers are aligned with each other through optical path on the VOA chip. The optical path is composed of air path and the shutter of a microstructure. In the conventional study, reflective materials such as Au, Al, Cu and so on are used as a coated material for the micro mirror or micro shutter to improve the optical performance of VOA. The optical performances are composed of polarization dependent loss (PDL), wavelength dependent loss (WDL), return loss (RL) and so on. The optical characteristics of VOA usually depend on the shape of micro shutter, and on the coated material of micro shutter and on optical path. This paper proposes a new shape of shutter and a dissipative material like titanium to improve the optical performances. The new VOA in this paper is fabricated using silicon micro machining process. The structure of VOA is fabricated by ICP (Inductively Coupled Plasma) deep etch process, with SOI (silicon-on-insulator) wafer, which has 80μm thick layer and 3μm thick oxide layer. The new proposed VOA shows fast response time of the MEMS actuator and the excellent optical performances such as PDL and WDL. This paper shows that new designed shape and proposed material of micro shutter are useful to get excellent optical performances, compared with conventional model.