The integrated-optic frequency shifter utilizes electro-optic polarization conversion by a travelling index grating in LiNbO3:Ti stripe waveguides. The optical frequency shift is equal to the frequency of two electric phase-quadrature drive voltages. A device operating at a fixed wavelength of 723 nm with an optical bandwidth of ~ 1 nm shows ≥90% conversion efficiency and ≥30 dB suppression of undesired sidebands at frequency shifts up to ± 10 6Hz.
Fred Heismann, Fred Heismann,
"In-Line Electro-Optic Frequency Translator For Fiber-Optic Sensors", Proc. SPIE 0517, Integrated Optical Circuit Engineering I, (29 January 1985); doi: 10.1117/12.945160; https://doi.org/10.1117/12.945160