Integrated Photonic Devices

Erbium Doped Waveguide Amplifiers (EDWA) Circuits

Mr. Ananth Subramanian

The goal of this project is to investigate potential materials for dense integrated circuits with gain, for a future generation of compact multifunctional planar lightwave devices. It is hard to achieve dense integration with conventional integrated optics due to the small index contrast between waveguide core and cladding. Circuit elements with gain are ubiquitous in electronics and required to achieve many functions, but gain in small space is much harder to obtain in optical circuitry, and it is a key aim of this project to explore the limits of gain in new materials optimised for dense circuitry. Towards these ends, we are exploring materials with low waveguide loss and better mode confinement, high Erbium (and Ytterbium) concentration and hence low threshold for oscillators (lasers), phonon energy engineered for efficient use of pump, wide band flat gain to realise broadband and multi-channel operation, high rare earth solubility without having concentration quenching effects to achieve large gain in an EDWA. The project initially involves the study of photoluminescence properties of erbium in candidate materials and the achievement of net gain (signal enhancement over absorption, coupling and insertion losses) followed by the realisation of laser in the IR or visible region. Finally, greater functionality such as WDM, mode locking will be demonstrated using χ(3) non-linearity, photonic crystals or photosensitivity to realise a fully integrated planar waveguide circuit.