Abstract

Optical frequency combs can be generated by cascaded four-wave mixing with Kerr nonlinearity. Recently, by taking advantage of the field enhancement effect in high quality (Q) factor cavities, comb generations using continuous wave (CW) laser have been demonstrated in various materials, such as silica toroids, doped silica glass ring resonators, silicon nitride micro-ring resonators, diamond micro-ring resonators, crystalline CaF₂ and MgF₂ micro-toroids and etc. Aluminum nitride (AlN) possesses strong Kerr nonlinearity which can be used to generate optical frequency comb by cascaded four wave mixing [1. Also it has strong Pockels effect which allows electro-optic modulation [2. Here, we take advantage of both effects and demonstrate comb generation using on-chip aluminum nitride microring, high speed switching of the optical frequency comb,[3 and cascaded frequency conversions among the comb lines. [4. (a) IR frequency comb generated in 60 µm radius microring resonator (left inset) with 650 nm height and 3.5 μm width structure (right inset). Estimated power in the bus waveguide is 600 mW and 0.5 % of gathered output power is used for spectrum measurement. (b) The greenly glowing microring under daylight. (c) The microscope image without a filter and (d) with a 750 nm long pass filter. (e) The microscope image with the 750 nm long pass filter when on-resonance (top) and off-resonance (bottom). The white dashed lines represent the bus waveguides and the white dotted boxes on the left represent the input fibers. The white arrows indicate the ends of the bus waveguides of the chip.

© 2015 Optical Society of America