Numerical and experimental study of a Few-Mode (FM) Erbium Doped Fiber Amplifier (EDFA) suitable for mode division multiplexing (MDM) is reported. Based on numerical simulations, a Few-Mode Erbium ...Doped Fiber (FM-EDF) has been designed to amplify four mode groups and to equally amplify LP11 and LP21 mode groups with gains greater than 20 dB and with a differential modal gain of less than 1 dB. Experimental results confirmed the simulations with a good concordance. This modal gain equalization is obtained by tailoring the erbium spatial distribution in the fiber core with a ring-shaped profile.
Several strong narrowband resonances are observed in the transmission spectra of fiber Bragg gratings photo-written in photonic crystal fiber that has a refractive index-neutral germanium/fluorine ...co-doped core. Experimental results for the strain, temperature and refractive index sensitivities of these mode resonances are reported and compared to those of conventional single mode fiber. In particular, we identify three kinds of resonances whose relative sensitivities to strain, temperature and refractive index are markedly different and present numerical simulations to explain these properties. Potential multiparameter optical sensor applications of these mode resonances are briefly discussed.
Owning to their intrinsic properties, silica-based glasses are widely used in various technological fields, especially in photonics. However, high degree of flexibility is yet challenging in ...realization of next-generation miniaturized optical components. In this work, we develop an approach based on ‶Solmers″ hybrid resins allowing versatile two-photon polymerization 3D printing of silica glasses with 23 nm resolution, doping with Germanium and/or rare-earths elements. Other dopants such as gold nanoparticles were also incorporated for localized metallization. After 3D printing and sintering (1100–1300 °C), high optical quality glasses with low surface roughness (<0.2 nm) were obtained. Structural analyses confirmed the amorphous structure of silica glasses. Various mono- or multi-materials microstructures were successfully fabricated on fused silica substrates. Besides, this approach was extended to the functionalization of optical fibers for optical sensing applications in harsh environment (1000 °C). Compared to organic or organic-inorganic materials, these dense silica-based glasses with enhanced optical and structural properties will open new avenues for the development of emerging advanced optical components.
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Hybrid Photonic Crystal Fibers with a first ring of high index inclusions are studied and compared to both standard air-hole fibers and all solid photonic bandgap fibers. In such new fibers a ...bandgap-like core mode exists over a wide spectral range and exhibits confinement losses ten orders of magnitude smaller than those of the corresponding all-solid fiber. This particular fiber supports also a core mode guided by modified total internal reflection at long enough wavelengths. The origin and properties of these two kinds of modes are discussed in details. Such a design can also act as a mode filter (as compared to the standard air-hole structure) and could also be used to ease phase matching conditions for nonlinear optics.
Few-Mode Erbium-Doped Fiber Amplifiers: A Review Bigot, Laurent; Le Cocq, Guillaume; Quiquempois, Yves
Journal of lightwave technology,
2015-Feb.1,-1, 2015-2-1, Letnik:
33, Številka:
3
Journal Article
Recenzirano
Space-division multiplexing has brought a fresh perspective to the optical fiber community over the last three years and many global players around the world have been involved with both the ...theoretical and the experimental questions raised by this promising approach. If this technology is to be introduced in the future optical fiber networks, this implies that most of the optical components of the transmission line, including the popular Erbium-doped fiber amplifiers that lie at the heart of fiber communications need to be reexamined. This study reviews the way the new generation of Erbium-doped fibers affects the recent findings on few-mode fibers and how they may further play a central role in the deployment of this technology.
High second-order susceptibility has been created in a chalcogenide glass from Ge-Sb-S system. A thermal poling process was used to produce this non-linear effect and a second harmonic generation ...experiment allowed characterizing the phenomenon. A maximum chi(2) value of 8.0+/-0.5 pm/V was measured for the first time to our best knowledge in sulfide glasses.
Gradient descent optimization algorithm is applied to design few-mode Er 3+ -doped fibers adapted to gain equalization over modes and wavelengths, for mode division multiplexing. Theoretical study is ...performed for fiber designs supporting six and ten spatial modes at signal wavelength. Flat gain is obtained by optimizing Er 3+ doping profile of a micro-structured core and modal composition of the pump beam.
In its standard implementation, spatially and spectrally resolved (S<inline-formula><tex-math notation="LaTeX">^2</tex-math></inline-formula>) imaging consists in recording near field intensity ...patterns as a function of the wavelength, followed by a Discrete Fourier Transform (DFT) to assess differential group delays, as well as optical power distribution between modes for the given injection as long as the higher-order mode powers are low. Here we present a variant of S<inline-formula><tex-math notation="LaTeX">^2</tex-math></inline-formula>-imaging which does not make use of DFT. The method is more robust to wavelength jitter of the laser source. Furthermore, in special cases, the method allows retrieving relative modal powers without constraints on HOM power.
In its standard implementation, spatially and spectrally resolved (SFormula Omitted) imaging consists in recording near field intensity patterns as a function of the wavelength, followed by a ...Discrete Fourier Transform (DFT) to assess differential group delays, as well as optical power distribution between modes for the given injection as long as the higher-order mode powers are low. Here we present a variant of SFormula Omitted-imaging which does not make use of DFT. The method is more robust to wavelength jitter of the laser source. Furthermore, in special cases, the method allows retrieving relative modal powers without constraints on HOM power.
In this work, a simple method based on optical time-domain reflectometry has been implemented to compare the Rayleigh scattering coefficient of different modes of few-mode fibers. The principle of ...the method is first validated in the case of single-mode fibers and then applied to two weakly-coupled few-mode fibers presenting different refractive index profiles. The results are compared with those obtained by more sophisticated experiments based on the analysis of the angular distribution of light scattering.
•Optical Time-Domain Reflectometry for mode dependent Rayleigh scattering analysis.•Impact of refractive index profiles on Rayleigh coefficients.•Comparing Rayleigh scattering coefficients in few-mode fibers.
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