Direct photofabrication of refractive-index-modulated multimode optical waveguide using photosensitive sol-gel hybrid materials

Photosensitive sol-gel hybrid materials (hybrimers) exhibited a thick film property, an efficient refractive index tunability through the control of their compositions, and a high photosensitivity upon UV exposure. The materials were used for the direct photofabrication of the multimode optical waveguide (MOW) with a large core structure. Due to the outstanding optical properties of these materials, problems and complexities associated with the fabrication of MOW could be overcome, and a MOW with good propagation performance could be easily fabricated. Importantly, a propagation loss of as low as $0.13dBcm−1$ at $850nm$ could be obtained.