Research Projects

Development of Optical Waveguide Devices Using Ultra-Violet (UV)-patternable Sol-gel Hybrid Materials

To develop passive planar waveguide devices including waveguide splitters and couplers as well as thermo- optic switches for photonic applications. 



  • Single mode rib and ridge waveguide
  • For rib waveguide, the dimension of the waveguide profile is 10µm x 8µm(micrometres) on a slab layer of 3µm. The refractive index difference between waveguide core and cladding is 0.04 to 0.05
  • For ridge waveguides, the dimension of the waveguide profile is 10µm x 8µm. The refractive index between core and cladding is 0.005
  • Waveguide propagation loss for rib waveguide is about 1.0dB/cm at 1550 nm.
  • Y splitter branching angle is between 2 and 10 degrees

SolutionThe problems with the existing silica waveguides can be solved by the organic-inorganic hybrid sol-gel coating developed by SIMTech. With the modified sol-gel fabrication process, thick coating for waveguide development can be easily fabricated and precise patterns can be fabricated using conventional photolithography processing. The mechanical, optical and chemical properties of the coating can be adjusted according to the requirement of the application conditions. Buried rib waveguide structure with high refractive index difference, or ridge waveguide structure with low refractive index difference can be fabricated.

ApplicationsThe main application area of this coating is for optical waveguide development for optical integration and passive waveguide devices in integrated optical and photonic systems. The hybrid coating can also be used for other surface patterns such as display and microfluidic devices

Problems Addressed

Planar optical waveguide devices are used in integrated optical circuits for optical network applications. Silica-based waveguides have been widely used in integrated optical devices due to their low optical losses and high temperature stability. However, there are a number of drawbacks with silica waveguides: high temperature processing, indirect patterning by dry or wet etching, low thermo-optic coefficient for thermo-optic devices such as switch and attenuator.