A flexible waveguide with an adjustable index of refraction. The core layer and/or the cladding layer of a flexible waveguide may include a plurality of nanoparticles having a different index of refraction than the core layer and/or cladding layer. The plurality of nanoparticles may have an index of refraction that is greater than or less than an index of refraction of either the core layer or the cladding layer in order that the overall effective index of refraction of either the core layer or the cladding layer can be adjusted.