Author Affiliations
1Tsinghua National Laboratory for Information Science and Technology, Department of Electronic Engineering, Tsinghua University, Beijing 100084, China2FiberHome Telecommunication Technologies Co., Ltd., Wuhan 430074, Chinashow less
Fig. 1. Schematic diagram of the RCF cross-section.
Fig. 2. Colormap of minimal Δneff between adjacent modes as a function of V and ρ. The curves show the corresponding cut-offs for each mode in the calculation region.
Fig. 3. Intensity distributions and electrical field orientations for the first higher-order eigenmodes, along with intensity and phase distributions for the composite modes in the RCF with different bending radii R. (a) Straight fiber, (b) R=10 mm, and (c) R=6 mm.
Fig. 4. (a) Effective refractive indices neff and (b) effective refractive index difference Δneff as a function of bending radius R.
Fig. 5. Conversion length LC as a function of bending radius R for different ρ and V.
Fig. 6. (a) Optical microscope image of fiber cross section for fiber 1. (b) Intensity profiles and spiral interference patterns for OAM±1,1 modes after propagating 2 m in fiber 1.
Fig. 7. (a) Experimental setup of the bending test. LD, semiconductor laser; CL, fiber collimator; BE, beam expander; Pol, polarizer; M, mirror; SLM, liquid crystal spatial light modulator; QWP, quarter-wave plate; LE, lens; HWP, half-wave plate; BS, non-polarizing beam-splitter. (b) Bend-post of the RCF. L is the length of the bending section, θ is bending angle, and R is the bending radius. (c) Output intensity profiles and corresponding interference patterns of fiber 1 for straight fiber, R=9 mm and L=20 mm, and R=9 mm and L=LC=43 mm, respectively.
Fig. 8. Experimentally measured and simulated values of bending lengths versus bending radii for three RCFs.
Fiber | (μm) | (μm) | | | (μm) |
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1 | 1.1 | 3.5 | | | 125.6 | 2 | 1.9 | 6.7 | 1.44 | 1.47 | 125.5 | 3 | 2.2 | 7.9 | | | 125.7 |
|
Table 1. Measured Parameters of Three RCFs