Fault-tolerant three-port fiber-optic attenuator using small tilt micromirror device

A programmable three-port fiber-optic attenuator is introduced using a small tilt micromirror device. Each port can be assigned to function as the input or the output port. Key features via the macro-pixel approach include digital control, alignment tolerance, and high speed. Experimental proof of concept demonstration using a two dimensional digital micromirror device (DMD™) shows a 37.8 dB dynamic range at the output port and a measured 20.4 dB maximum optical attenuation at the monitoring port with an 11-bit resolution. The measured optical loss at the output port is 8 dB and is limited by the visible design DMD™, the freespace coupling efficiency, and a fiber adapter.