Abstract

While typical vertical-cavity Fabry-Perot optical modulators are amplitude switches, we have previously demonstrated that it is possible to make a vertical-cavity phase-flip modulator that maintains the same reflected amplitude but varies reflected phase from 0 to 180° between the off and on states.¹ We have used these latter devices to create a single-element electrically controlled phase-diffraction grating operating at 7 V bias. Because each of the grating elements modulates phase rather than amplitude (and thus each of the stripes is always highly reflective), the array is extremely efficient. A schematic of a first device is shown in Fig. 1. With zero bias, all stripes reflect with the same phase. When Mas is applied to the structure, all stripes still reflect, but only alternating stripes feel the applied bias, and thus a phase grating is created with 0°–180°–0°–180° reflected phase. This phase-modulated diffraction grating reflects normal incident light into the first-order diffraction peaks. We describe the creation fabrication, and response of this device as well as the creation of a variable pitch phase grating and efficiency issues both from individual device and away considerations.

© 1996 Optical Society of America