RESUMEN
In space-division-multiplexed transmission systems, it is essential to realize fan-in/fan-out devices that connect the cores between multicore fibers and single-mode fibers. In this Letter, we propose a metasurface-based fan-in/fan-out device with nonuniform phase plates for heterogeneous 19-core fibers across the full C band. Our results show that an average insertion loss of 0.85â dB and a maximum crosstalk of -25.5â dB can be achieved at 1550â nm. Across the C band, the insertion loss and crosstalk are better than 2.78â dB and -19.96â dB, respectively. The proposed concept can flexibly handle various fiber configurations without additional complexity.
RESUMEN
In this Letter, we show numerically and experimentally that multipath interference can be reduced significantly by distributed Raman amplification (DRA) in quasi-single-mode transmission using few-mode fibers, owing to the extra differential mode attenuation induced between the fundamental mode and higher-order modes. The experimental results show that the required number of equalization taps can be reduced by 1.6 times. Moreover, by carefully optimizing the intensity overlap between the LP01 and LP11 modes through structural adjustment of the two-mode fiber, a 3.5-times reduction in the required number of taps can be obtained.
RESUMEN
Polarization-maintaining few-mode fibers (PM-FMFs) have found applications in sensors with attractive features that traditional single-mode fibers do not possess. We propose a measurement method for multi-parameter sensing based on PM-FMFs. This method is mainly based on the polarized interference effect of PM-FMF. We experimentally demonstrate the principle of the simultaneous sensing of temperature, strain and transverse force. The sensor has been verified by three groups of multi-parameter measurement experiments showing that the changes of multi-parameter derived from the wavelength shift of the polarized interference spectrum are consistent with the multi-parameter changes set in the experiments. The proposed PM-FMF based sensor has a temperature sensitivity of 0.3â nm/°C, a strain sensitivity of 0.01â nm/µÎµ and a transverse force sensitivity of 0.0065â nm/(N/m).
RESUMEN
We experimentally demonstrate adaptive variable-forgetting-factor (VFF) recursive-least-square frequency-domain equalization (RLS-FDE) for mode-division multiplexing. The VFF-RLS-FDE algorithm improves convergence speed as transmission distance increases. For MDM transmission over a 1,000-km few-mode fiber, the convergence speed was increased by 18.7 times in comparison with LMS-FDE. In the meantime, the convergence error performance of VFF-RLS is also much superior to LMS while fixed-forgetting-factor RLS has a 0.2 dB penalty compared with LMS. The proposed VFF-RLS algorithm achieves better performances than conventional RLS in terms of convergence speed and convergence error.
RESUMEN
We summarize theoretical formulae for determining the intrinsic loss of few-mode fibers and compare intrinsic losses among step-index and parabolic graded-index few-mode fibers (FMF) with different dopants, and with single-mode fibers (SMF). The low-loss characteristics of pure-silica-core FMFs, in comparison with SMFs, give rise to additional motivations for pursuing mode-division multiplexed transmission over parallel-SMF transmission, and quasi-single-mode (QSM) transmission over ultra-large-area SMF transmission.
RESUMEN
We demonstrate the first few-mode-fiber based passive optical network, effectively utilizing mode multiplexing to eliminate combining loss for upstream traffic. Error-free performance has been achieved for 20-km low-crosstalk 3-mode transmission in a commercial GPON system carrying live Ethernet traffic. The alternative approach of low modal group delay is also analyzed with simulation results over 10 modes.