Low power reconfigurability and reduced crosstalk in integrated photonic circuits fabricated by femtosecond laser micromachining

Understand

Femtosecond laser writing is a powerful technique that allows rapid and cost-effective fabrication of photonic integrated circuits with unique three-dimensional geometries.

• In particular, the possibility to reconfigure such devices by thermo-optic phase shifters represents a paramount feature, exploited to produce adaptive and programmable circuits.
• However, the scalability is strongly limited by the flaws of current thermal phase shifters, which require hundreds of milliwatts to operate and exhibit large thermal crosstalk.
• In this work, thermally-insulating three-dimensional microstructures are exploited to decrease the power needed to induce a 2{\pi} phase shift down to 37 mW and to reduce the crosstalk to a few percent.