Optical fibers are
a key component in modern photonics, where conventionally
used polymer materials are derived from fossil-based resources, causing
heavy greenhouse emissions and raising sustainability concerns. As
a potential alternative, fibers derived from cellulose-based materials
offer renewability, biocompatibility, and biodegradability. In the
present work, we studied the potential of carboxymethyl cellulose
(CMC) to prepare optical fibers with a core-only architecture. Wet-spun
CMC hydrogel filaments were cross-linked using aluminum ions to fabricate
optical fibers. The transmission spectra of fibers suggest that the
light transmission window for cladding-free CMC fibers was in the
range of 550–1350 nm, wherein the attenuation coefficient for
CMC fibers was measured to be 1.6 dB·cm
–1
at
637 nm. CMC optical fibers were successfully applied in touch sensing
and respiratory rate monitoring. Finally, as a proof-of-concept, we
demonstrate high-speed (150 Mbit/s) short-distance signal transmission
using CMC fibers (at 1310 nm) in both air and water media. Our results
establish the potential of carboxymethyl cellulose-based biocompatible
optical fibers for highly demanding advanced sensor applications,
such as in the biomedical domain.