Fabrication of graded index waveguides in azo polymers using a direct writing technique

Fast direct writing of waveguides on polymers using low power continuous-wave lasers has been investigated. Using the cis-trans property of a functionalized sulfonated azo chromophores, we have fabricated graded index waveguides with low loss, which is due to graded index sidewalls. Fabrication is done by exposing the polymer film to a 532 nm wavelength laser beam focused to about 5 μ m spot at the film. Losses were calculated to be 0.48 ± 0.04 dB ∕ cm at 830 nm wavelength with no surface deformation. This technique enables us to fabricate integrated optical circuits including directional couplers, dividers, filters, switches, etc., as they are currently investigated in our laboratory.