Integrated Microsphere Planar Lightwave Circuits

Planar lightwave circuits (PLCs) offer a rugged, low-cost, mass-manufacturable route to the device requirements of future telecommunications systems. Barriers to full exploitation of conventional PLC technologies include the longh path lengths required for many optical interactions and the difficulty in producing tight waveguide bends with low loss, both of which limit the density of integration and the scale of mass-manufacture. Microsphere resonators, primarily demonstrated so far coupled to tapered fibres, have the potential to become key components in photonic circuits, providing feedback, wavelength selectivity and energy storage to allow dispersion control and enhanced nonlinearity, resonant filtering, waveguiding with low bend radius and ultra-low threshold lasing. Many of these properties stem from strengthening the interaction of light with the material through high-Q resonance. Planar lightwave circuits present an ideal platform for the precise placement of individual microspheres or arrays of microspheres, to realise highly functional circuits in a more robust configuration than fibre devices. We propose to explore the enhancement of conventional waveguide technologies by realising microspheres from advanced glasses with tailored optical properties, positioning them in PLCs using self-assembly techniques, and realising a wide range of passive, lasing and nonlinear switching devices.