Reconfigurable slow light in phase change photonic crystal waveguide

Abstract

Experimental demonstration of light propagation with ultralow group velocity, i.e., slow light, allows for revolutionary solutions for time-domain processing and buffering of optical signals. It can spatially compress optical energy, which lessens the device footprint and enhances linear and nonlinear optical effects. Photonic crystal waveguides (PCWs) are appealing for producing slow light since they can be on-chip integrated and operated under room temperature. However, most PCW slow-light devices are restricted to the narrow spectral range of material resonance, leading to a small delay-bandwidth product, which restricts the maximum data rate, operation frequency, and storage capacity. Furthermore, the lack of broadly tunable slow light hinders practical applications in tunable photonic devices. We propose a reconfigurable slow-light device using a PCW based on a prototypical chalcogenide glass, Ge2Sb2Te5 (GST225) to solve the problems. We find that the operating wavelength of the slow light within the structure can be reversibly switched between 3575 and 4905 nm by changing the structural state of GST225 between amorphous and crystalline ones. The corresponding average group indices are 40.8 and 54.4, respectively. We experimentally illustrate that the reversible phase transition of GST225 between amorphous and crystalline ones can be realized in nanoseconds. Our proof of concept may provide a platform for actively engineering slow light that might otherwise be difficult to obtain in photonic systems. We expect it to improve the device performance in the fields of nonlinearity and sensing.

Integrated Hybrid Mode‐Wavelength Demultiplexers Based on Cascaded Digital Metamaterials

“…[ 1–13 ] Silicon photonics has been regarded as a promising platform for the realization of on‐chip demultiplexers, due to its outstanding advantages, such as the ultrahigh‐index contrasts and the complementary metal–oxide–semiconductor compatibility. [ 14–25 ] Silicon‐based wavelength‐division‐multiplexing (WDM) technology is proved to be one of the most successful technologies, which enables signals with different wavelengths to carry information in a single channel simultaneously. [ 1–6 ] Other dimensions also have been introduced to diversify the multiplexing technologies.…”

Slow Light Effect and Tunable Channel in Graphene Grating Plasmonic Waveguide

“…Slow-light technology can be applied to non-linear optical devices [1,2], integrated interferometers [3], and all-optical information devices such as optical buffers [4], optical storage devices [5], optical switches [6][7][8], and so on. So far, electromagnetic induced transparency [9][10][11], coherent population oscillation [12], stimulated Brillouin scattering [13], photonic crystal waveguide [14], coupling resonance transparency technology [15] and plasmonic waveguide [16] have been found to achieve the slow-light effect.…”