Kovacs-like memory effect mediated fiber Bragg grating: resembling a silica quipu

Abstract

In antiquity, civilizations employed stone carvings and knotted quipu cords for information preservation. Modern telecommunications rely on optical fibers - silica glass strands engineered for light transmission - yet their capacity as archival media remains untapped. This study explores a novel fiber Bragg grating (FBG) configuration exhibiting thermally programmable memory effects for optical data storage. Capitalizing on temperature-dependent spectral characteristics, we demonstrate finite spectral tuning through controlled thermal annealing, achieving irreversible spectral modifications via a light-induced stress mechanism analogous to the Kovacs memory effect in glassy materials. The engineered dual-dip FBG architecture enables multiplexed wavelength encoding, functioning simultaneously as a thermal history recorder and laser-writable data medium - mirroring the information knots of ancient quipu devices. This optical quipu concept pioneers one-dimensional photonic memory technology, opening new avenues for optical fiber applications in the information age.