Thermally reconfigurable broadband silicon photonic splitter

Abstract

We demonstrate a thermally reconfigurable broadband silicon photonic coupler/splitter based on deep photonic network architecture that overcomes wavelength-dependent tunability limitations in conventional devices. The device employs 8 cascaded Mach–Zehnder interferometer layers (700 μm total length) with 30 thermally controlled arms and custom waveguide tapers. Using automatic differentiation-based optimization, thermally tuned taper geometries achieve arbitrary optical transfer functions. The structure dynamically reconfigures post-fabrication to multiple power splitting ratios (0-100% through 100-0% in 10% increments) with < 2% deviation from target across the 1.5-1.6 μm wavelength range. This represents the first thermally tunable ultra-broadband splitter design in a fully silicon-based architecture, eliminating the need for dedicated layouts for each splitting ratio or optical function. The approach enables universally programmable broadband silicon photonics, offering significant advantages for communications, computing, and sensing applications requiring wavelength-agnostic reconfigurable optical functionality.