All-optical phase control in nanophotonic silicon waveguides with epsilon-near-zero nanoheaters

Abstract

A wide variety of nanophotonic applications require controlling the optical phase without changing optical absorption, which in silicon (Si) photonics has been mostly pursued electrically. Here, we investigate the unique light–matter interaction exhibited by epsilon-near-zero (ENZ) materials for all-optical phase control in nanophotonic silicon waveguides. Thermo-optic all-optical phase tuning is achieved using an ENZ material as a compact, low-loss, and efficient optical heat source. For a 10-$$\upmu $$ μ m-long ENZ/Si waveguide, insertion loss below 0.5 dB for the transverse electric (TE) polarization is predicted together with a high control efficiency of $$\sim 0.107\uppi $$ ∼ 0.107 π $$\hbox {mW}^{-1}$$ mW - 1 . Our proposal provides a new approach to achieve all-optical, on-chip, and low-loss phase tuning in silicon photonic circuits.

Propagation characteristics of single and multilayer Ga:ZnO in the Epsilon near zero region

“…Incorporating ENZ materials inside meta-surfaces empowers various appealing functionalities such as enhanced nonlinearity [8], tunable electro/all-optical switch [9], dynamic polarization control [3], tunable amplitude modulation [10], integrated terahertz generator-manipulators [11], coherence switching [12], etc. Waveguide structures including ENZ materials have been shown to realize modulators[1, 13,14], switching [2], all-optical phase control [15], tunable coherent perfect absorption [16], luminescence enhancement of quantum emitters [17], etc. Thin films of ENZ materials render interesting functionalities such as enhanced high harmonic generation [18][19][20][21],…”

All-optical switching in epsilon-near-zero asymmetric directional coupler

“…These characteristics of ENZ TCO can provide possibilities for breaking the limitations of traditional all-optical waveguide logic gates. To date, all-optical ENZ switches are mostly based on metasurfaces 20 , 21 or bulk 22 structures, and the reported ENZ-related all-optical waveguide devices are mainly phase modulation designs 23 , 24 . Therefore, it is necessary to explore its form as all-optical switch in integrated photonic systems.…”