Scientists at the Swiss Federal Laboratory of Materials Science and Technology have developed an optical fiber with a liquid glycerin core that is stronger and can transmit data just as reliably as conventional fiber lines. The fibers could even be used to build microhydraulic components and light sensors.

We know that fiber optic lines are ideal for long-distance data transmission, as long as the fiber does not break, data and signals can be transmitted quickly and reliably through glass fiber optics. However, glass fibers can only bend to a limited extent and are very sensitive to tensile stresses, which can quickly destroy conventional fibers if they are bent or stretched too strongly. The Achilles' heel of conventional fiber optics is the scattering and loss of light from microcracks in the fiber core, whether plexiglass or polycarbonate.

To that end, scientists at the Swiss Federal Laboratory of Materials Science and Technology tried various ways to improve the optical polymer fibers, and ultimately found that even with the best solid fiber cores, they could never offer as many benefits as fluid-filled fibers.

The experiment paid off: the Swiss Federal Laboratory for Materials Science and Technology team produced liquid-filled polyolefin and polyamide filaments ranging in diameter from 45 to 200μm microns and containing up to 25vol% by volume. The resulting fiber can withstand tensile rates of up to 10 percent and then return to its original length, which is impossible with other conventional solid core fibers.

The scientists added a small amount of fluorescent dye to glycerin and checked the optical properties of the glowing fibers during the stretching process. It turns out that when the fiber is stretched, the path of light is lengthened, but the number of dye molecules in the fiber remains the same. This causes small changes in the color of the emitted light, so the liquid-core fiber can be used not only for signal transmission and sensing, but also for force transmission in micromotors and microhydraulic systems.

However, the new core material also brings great challenges to optical fiber processing in applications. How the liquid-core fiber is applied to the optical module, how the liquid-core fiber performs splicing, and whether it can be combined with ordinary single-mode fiber or polarization-maintaining fiber splicing. What kind of fusion splicers will adapt this fiber processing.This creates new questions for fiber solution.