Reversibly Programmable Photonics via Responsive Polyelectrolyte Multilayer Cladding

Abstract

Reversibly programmable photonic integrated circuits (PICs) that can facilitate multifunctionality have been long sought after to deliver user‐level design flexibility. Issues like complicated control, continuous power consumption, and high optical losses hinder their large‐scale adaptation. In this work, a novel approach toward programmable photonics using a responsive polyelectrolyte multilayer (PEM) cladding is presented. Reversible (de)swelling of PEMs by consecutive exposure to acidic and neutral pH solutions yields highly contrasting refractive index changes in the dry film. Utilizing this effect, an easily applied technique for programming photonic integrated devices with two different approaches, complete and area‐selective deposition, for several reversible cycles is demonstrated. These devices operate at two distinct states that are virtually lossless and nonvolatile. This proof‐of‐concept demonstration is suitable for various photonic integration platforms to facilitate reconfigurable photonic processors, static memories, and fine‐tuning of fabrication related limitations. Therefore, these results are the first step toward PEM‐assisted reversibly programmable multipurpose PICs for low‐cost mass production.

Single-Step Application of Polyelectrolyte Complex Films as Oxygen Barrier Coatings

“…For the PEI/PAA ratios 4:1–2:1, the films did not dissolve, clearly indicating complex formation. After stirring, the films became swollen and turned white, similar to previous observations for polyelectrolyte multilayers based on similar PEs; this can be explained by the formation of water pockets that leads to a porous structure. − However, for the ratios 1:1–1:3, the films did dissolve in water. The excess of negative charge allows for the formation of soluble complexes, resulting in the removal of the films.…”

PAWS and POCO: NIR Astrophotonic Instruments for Astronomy

“…Alternatively, if the output waveguides of the AWG are not diced, and are spaced to match the pixel pitch of a given line array detector, then by actively tuning the path lengths of the waveguide arrays, one could “scan” the discrete channels to form a continuous spectra. Such active scanning can be attempted in the future using tunable materials for programmable photonics (Mohammed, Sproncken, et al 2020; Mohammed, Melskens, et al 2020).…”