A nanosecond response waveguide electro-optic(EO) switch based on ultraviolet(UV) sensitive polymers of Norland optical adhesive(NOA73) and Dispersed Red 1(DR1) doped SU-8(DR1/SU-8) is designed and fabricated. The absorption properties, refractive indexes, and surface morphologies of NOA73 film are characterized. The single-mode transmission condition is computed by the effective index method, and the percentage of optical field distributed in EO layer is optimized to be 93.78 %. By means of spin-coating, thermal evaporation, photolithography, and inductively coupled plasma etching,a Mach–Zehnder inverted-rib waveguide EO switch with micro-strip line electrode is fabricated on a silicon substrate.Scanning electron microscope characterization proves the physic-chemical compatibility between NOA73 cladding and DR1/SU-8 core material. The optical transmission loss of the fabricated switch is measured to be 2.5 d B/cm. The rise time and fall time of switching are 3.199 ns and 2.559 ns, respectively. These results indicate that the inverted-rib waveguide based on UV-curable polymers can effectively reduce the optical transmission loss and improve the time response performance of an EO switch.
Visible light variable optical attenuators(VOA) are essential devices in the application of channel power regulation and equalization in wavelength-division multiplexing cross-connect nodes in plastic optical fiber(POF) transmission systems.In this paper, a polymer/silica hybrid waveguide thermo–optic attenuator based on multimode interference(MMI) coupler is designed and fabricated to operate at 650 nm. The single-mode transmission condition, MMI coupler, and transition taper dimensions are optimized through the beam propagation method. Thermal analysis based on material properties provides the optimized heater placement angle. The fabricated VOA presents an attenuation of 26.5 dB with a 21-mW electrical input power at 650 nm. The rise time and fall time are 51.99 and 192 μs, respectively. The time–stability measurement results prove its working reliability.
