All-optical switch and modulator using photochromic dye doped polymer waveguides

We have fabricated all-optical 1×2 Y-branch switch and Mach-Zehnder modulator using photochromic dye doped polymer waveguides. The photochromic dye undergoes reversible structural change from the open form (low refractive index) to the closed form (high refractive index) by irradiation with ultraviolet (365 nm) light and in the reverse direction by irradiation with visible (514 nm) light. The 1×2 Y-branch switch exhibited a cross talk of about -14 dB and the Mach-Zehnder modulator exhibited an extinction ratio of about -12 dB at the wavelength of 1.55 μm using the ultraviolet (365 nm) and visible (514 nm) lights. A simple kinetic model has been used to calculate the refractive index change by the induced photochromic effect. The evolution of the refractive index change is successfully applied to predict the evolution of modulation characteristics.