Multiplication operation of an optical frequency shifter using cascaded electrooptic traveling phase grating

Electrooptic frequency shifters operating at higher modulation frequency will enhance the performance of current applications such as pulse characterization and optical sensing. Previously, we demonstrated frequency shifting of 16.25 GHz with the efficiency of 82% on the basis of Bragg diffraction from a sinusoidal electrooptic traveling-phase grating (ETPG). In this paper, we will demonstrate a new scheme to increase the shifting frequency to plusmn32.5 GHz using 16.25 GHz modulation source. The shifting frequency multiplication is achieved by successive Bragg diffraction from the cascaded ETPG.