Nano-wire photonics circuits for astronomical applications

High refractive index contrast waveguides with tight optical mode confinement are becoming indispensable in densely integrated high-resolution (R=Δ/Δλ~60,000) micro-spectrographs (MSG) for astronomical and biomedical applications. This paper presents first experimental results with alternative material technology (Silicon nitride-on-Silica) for Astrophotonics applications with useful optical properties such as high-nonlinear coefficient, absence of two-photon absorption, allowing integration of high-Q ring-resonator calibration sources on the same platform. Several nanowire devices such as Multi-Mode interference (MMI) photonic power splitters, MMI-Cross/Bar switches, Mach-Zehnder Interferometer (MZI), were designed using finite element method and BPM simulations (RSoft). The waveguide core was designed to be 600×750nm² for single-mode operation in the entire C-band. Access waveguide separation was reduced to 15μm, in contrast to the standard 125-250μm, in order to permit high integration density of waveguides.