RESUMO
A new configuration of mode-dependent-loss (MDL) equalizer for two linearly-polarized mode transmission systems using the silica planar lightwave circuit platform is proposed. This device acts as an LP01-mode attenuator (precisely, LP01/LP21 mode converter) to adjust the MDL keeping a high transmission of the LP11 modes. Almost all components constructing the device are based on the adiabatic mode conversion, which brings broadband operation. Especially, a newly proposed E12/E22 mode converter plays a key role in broadband MDL equalization. It is numerically revealed that the flattened spectra with designated transmission can be obtained for the wavelength from 1200â nm to 1650â nm.
RESUMO
A silica-based LP11 mode rotator, which is one of the basic and indispensable optical components for space division multiplexing, with multiple tapered trenches is proposed. Compared with the conventional interference-based LP11 mode rotator with a simple L-shape waveguide, the proposed LP11 mode rotator has many advantages in a mode conversion efficiency, an insertion loss, and a fabrication tolerance because the operation principle is based on the adiabatic mode conversion. By using an approach of the shortcut to adiabaticity, the proposed device is effectively miniaturized rather than the standard tapered structures. Among the LP11 mode rotators in the silica-based mode multi/demultiplexers, the proposed type will be a considerably promising candidate.
RESUMO
We propose a technique for reducing the differential modal gain (DMG) that occurs in a two-mode erbium-doped fiber (2M-EDF) by inscribing voids in the core center of a 2M-EDF with a femtosecond laser. We show that an empty void inscribed at the core center can attenuate the linearly polarized (LP01) mode selectively while suppressing excess loss for the LP11 mode. We also reveal that DMG can be controlled by means of void diameter. The longitudinal position dependence of the void in a 2M-EDF was also investigated considering its influence on gain and noise figure (NF) characteristics. Finally, we realize a sufficiently low DMG of less than 0.5 dB in the full C-band as well as a sufficient gain and NF by using the proposed technique.
RESUMO
We investigated the inter-core differential mode delay (DMD) characteristic of a weakly-coupled homogeneous multi-core fiber with a view to utilizing inter-core crosstalk compensation with MIMO processing. We confirmed experimentally that the bend induced inter-core DMD is lower than the simulated results, which we expected owing to the twist of the fiber. We also revealed numerically that the refractive index profile variation of each core greatly increases inter-core DMD. Finally, we conducted a 4 × 4 MIMO transmission experiment using a weakly-coupled 4-core fiber and successfully compensated for the inter-core crosstalk.
Assuntos
Desenho Assistido por Computador , Análise de Falha de Equipamento/métodos , Modelos Teóricos , Fibras Ópticas , Espalhamento de Radiação , Ressonância de Plasmônio de Superfície/instrumentação , Simulação por Computador , Desenho de Equipamento , LuzRESUMO
We demonstrate bidirectional transmission over 450 km of newly-developed dual-ring structured 12-core fiber with large effective area and low crosstalk. Inter-core crosstalk is suppressed by employing propagation-direction interleaving, and 409-Tb/s capacities are achieved for both directions.
Assuntos
Algoritmos , Artefatos , Redes de Comunicação de Computadores/instrumentação , Tecnologia de Fibra Óptica/instrumentação , Telecomunicações/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento , Micro-OndasRESUMO
We describe a coherent optical MIMO transmission experiment that employs a digital coherent receiver with a mode convergence unit, which converges higher-order mode light into the fundamental mode while maintaining the phase and amplitude information of the higher-order mode. The coherent optical MIMO transmission of two 10 Gbit/s BPSK signals over 20 km of graded-index multi-mode fiber was successfully achieved by using this mode convergence unit. We also show numerically that multi channel signals for a coherent optical MIMO transmission can be recovered by employing sufficient mode diversity, even if mode conversion occurs in the transmission fiber.
RESUMO
We propose a transmission distance-independent technique for modal dispersion compensation over few-mode fiber that uses a single-input multiple-output configuration and adaptive equalization. Our technique can compensate for the modal dispersion of a signal with 1-tap FIR filters regardless of the amount of modal delay difference, and enables us to utilize fiber with a large core and few modes as a long-haul transmission line. We also show numerically the advantage of few-mode photonic crystal fiber (PCF) for realizing a larger effective area (A(eff)), and finally we report a transmission over a large-core two-mode PCF with A(eff)>280 µm(2).
RESUMO
We show that any optical pulse train recovers its original waveform after passing through a group velocity dispersion (GVD) device when the total GVD value of the device is equal to an integral multiple of 1/(2πf(rep)(2)), where f(rep) is the repetition rate of the optical pulse train. In addition, we detail our proposed GVD measurement method, or optical phase-modulation (PM) method, which utilizes a sinusoidally PM continuous wave (CW) light as a probe light. The total GVD B(2) of a device under test (DUT) is derived by using a very simple equation, |B(2)|=1/(2πf(null)(2)), where f(null) is the smallest modulation frequency at which the sinusoidally PM light becomes CW light again after passing through the DUT.