Electro-Optic Raman–Nath Modulator Using Cascaded Periodically Poled Gratings

We propose a new type of electro-optic modulator consisting of cascaded periodically poled Raman-Nath gratings as a building block of a 1-D spatial light modulator with a wide acceptance angle. The modulator has two grating stages of harmonic periods for an enhancement of extinction ratio. The device was designed through the beam propagation method simulation, and fabricated in MgO:LiNbO3. An extinction ratio >50 was accomplished at ~150 V driving voltage.