Widely tunable polymeric Bragg wavelength filters operating bymechanical strain

摘要

A tunable wavelength filters with Bragg grating are fabricated on a flexible substrate by using a post lift-off processalong with an absorbing layer in order to provide highly uniformity of Bragg grating patterns. When the Bragg grating isfabricated on a flexible substrate, the highly elastic property of polymer is favorable to obtain much wider tuning rangethan the silica fiber. The flexible Bragg reflector shows narrow bandwidth, which is convincing the uniform gratingstructure fabricated on plastic film. By stretching the flexible polymer device, the Bragg reflection wavelength is tunedcontinuously up to 45 nm for the maximum strain of 31,690 which is determined by the elastic expansion limit ofwaveguide polymer. From the linear wavelength shift proportional to the strain, the photoelastic coefficient of the ZPUpolymer is found.