Photoelastically induced light modulation in gradient-index lenses

A new photoelastic light modulator is demonstrated based on the modulation of the birefringence and of the index profile in graded-index lenses. Using the birefringence modulation, we obtained a 35% modulation depth in a quarter-pitch lens and a 65% modulation depth in a half-pitch lens at acoustic frequencies up to the megahertz range. Using the index profile modulation in a half-pitch lens as a fiber-to-fiber connector, we obtained 15% modulation without the incorporation of a polarizer.