Using Bessel Beams to Induce Optical Waveguides

Optical fabrication of waveguides in a volume is limited by diffraction in the writing beams. We demonstrate the use of nondiffracting waves in the form of Bessel beams to fabricate scalable optical wiring through direct writing in a photosensitive volume. Experiments are performed in paraelectric potassium-lithium-tantalate-niobate (KLTN), where writing occurs through photogenerated space charge while guiding and electro-optic functionality are supported by the quadratic electro-optic effect. The method allows components to be integrated sequentially without interfering with each other during fabrication, an intrinsic superposition property that is used to realize single, double, and multiple waveguides, and 1 × 2, 1 × 3, and 1 × 4 splitters, and electrically controlled optical switching.