Stable single mode laser sources and optical heterodyne receivers are needed for high capacity single-mode fiber communications systems. An important component for both sources and receivers is an optical frequency translator. This device yields a frequency-shifted replica of an input optical signal. Ideally the amount of the frequency shift should be electronically controllable. Frequency translators are also needed for heterodyne optical spectroscopy. The PI has recently demonstrated optical frequency shift of up to 12 GHz using interactions with microwave magnetostatic waves in magnetic garnet thin films. Shifts of up to + 20 GHz should be possible using this technique. Advantages over electro-optical and acousto-optical frequency translators include single-sideband frequency shifts, continuous electronic tunability over the range 1-20 GHz via a magnetic bias field, selectable up or down frequency shifts, and a frequency-independent output beam angle.
