A MEMS blue/green retroreflecting modulator for underwater optical communications

Short range, high bandwidth underwater optical communications links are potentially useful for retrieving stored information from underwater systems. However many underwater systems have limited power capacity or limited weight budget. The use of a modulating retroreflector eliminates the need for a transmitting laser on the data bearing platform and reduces the pointing requirements by retroreflecting the modulated light back to the interrogating source. Blue/green operation of a MEMS Fabry-Perot modulator was demonstrated at data rates of 500 kbps and 1 Mbps in a 7.7 meter tank with water conditions varied by the addition of Maalox as a scattering agent.