Fiber Bragg gratings operating across arbitrary wavelength ranges

Abstract

We demonstrate that fiber Bragg gratings in polymer optical fibers can lead to reflection peaks in any wavelength range when exciting high-order propagation modes, which can enhance the design of sensing systems for specific applications.

Multimode interference-based strain sensing using micro dry-etched perfluorinated polymer optical fibers

“…1) Among POFs, perfluorinated (PF-) POFs 2) have garnered particular interest owing to their lower light propagation loss in the telecommunication wavelength band compared to other types of POFs, paving the way for significant advancements in PF-POF-based sensing applications. [3][4][5][6][7][8][9] Typically, PF-POFs possess a three-layer structure consisting of a PF acrylic core (50-120 μm in diameter), a cladding layer (several tens of μm thick), and a polycarbonate reinforcement layer (several hundred μm thick). The sensing characteristics of PF-POF sensors are greatly influenced by these reinforcement layers.…”

Spectral power stabilization against temperature variations in multimode fiber Bragg gratings

“…Figure 1 shows that, when broadband light is injected into the MM-FBGs, peaks emerge at each Bragg wavelength corresponding to the diffraction order m. This phenomenon occurs because peaks associated with higher-order modes appear around the most prominent peak that corresponds to the fundamental mode. [22][23][24] The Bragg wavelength for the fundamental mode, i.e. m = 1, can be expressed as λ B = 2 • n • Λ, where λ B refers to the Bragg wavelength for the fundamental mode, and n represent the refractive index at the center of the MMF core.…”