Slow light waveguides for hybrid systems

Zhaoming Zhu

Xiaorun Zang, Jianji Yang, Rémi Faggiani +8 more

One path to quantum information processing involves light-matter interaction, such as light in a photonic-crystal waveguide coupled to a cloud of ultracold alkali atoms. However, to actually implement such a system, it is crucial to increase the coupling strength beyond what is presently achievable. The authors explain the design requirements to achieve large coupling by decreasing the group velocity of an edge mode in a hybrid-clad waveguide, allowing photons of ``slow light'' to interact with trapped cold atoms in a robust, chip-integrated setting.

Ryan Hamerly, Kambiz Jamshidi, Hideo Mabuchi

Due to their strong light confinement, waveguides with optical nonlinearities may be a promising platform for energy-efficient optical computing. Slow light can enhance a waveguide’s effective nonlinearity, which could result in devices that operate in low-power regimes where quantum fluctuations are important, and may also have quantum applications including squeezing and entanglement generation. In this manuscript, slow-light structures based on the Kerr (χ(3)) nonlinearity are analyzed using a semi-classical model to account for the quantum noise. We develop a hybrid split-step / Runge-Kutta numerical model to compute the mean field and squeezing spectrum for pulses propagating down a waveguide, and use this model to study squeezing produced in optical waveguides. Scaling relations are explored, and the benefits and limitations of slow light are discussed in the context of squeezing.

Alexander Rebane, R. N. Shakhmuratov, Patrice Mégret +1 more

Jianhua Ji, Xuemei Chen, Ke Wang +3 more

Thomas P. White, Andrey A. Sukhorukov

We describe the generic effects of loss or gain on pulse propagation in photonic-crystal and plasmonic waveguides that support ``frozen'' or ``in-band'' slow light at dispersion inflection points in the absence of loss (or gain). Using an analytical perturbation theory, we find that propagating and evanescent modes hybridize when loss exceeds a certain threshold, resulting in a reduced attenuation rate and switching from slow to superluminal velocity. Numerical simulations for photonic-crystal waveguides reveal the dynamic nature of this transition with forward-backward pulse velocity oscillations for loss above the threshold. Importantly, we show that the light intensity is enhanced close to the input end of the waveguide even under strong material losses, indicating the potential for slow-light enhancement of optical effects, even in such lossy waveguides.