Wavelength sensitivity of the excited single mode in the output Multimode fiber of an SMm structure
01 Feb 2015-pp 1-4
TL;DR: It is shown that the change in source wavelength deteriorates the single mode excitation of the output fiber of an SMm structure, but the same performance can be re-established by changing the length of the middle MMF.
Abstract: Single mode - Multimode - Multimode (SMm) fiber structure provides a simple and cost effective method for exciting a single radial mode in a multimode fiber (MMF). The structure can be effectively utilized in improving the capacity of high speed communication links employing MMFs. In this work, we study the effects of change in source wavelength on the excited single mode in the output MMF of an SMm structure. We show that the change in source wavelength deteriorates the single mode excitation of the output fiber. However, the same performance can be re-established by changing the length of the middle MMF. For small changes in the wavelength, we also give a simple formula to predict the required change in the length.
Citations
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01 Jan 2008
TL;DR: In this article, the authors proposed a mode-field matched center-launching technique by fusion-splicing a single-mode fiber (SMF) pigtailed transmitter to the MMF, where the splicing condition is optimized to expand the core of SMF slightly so that it can match the mode field distribution of the fundamental mode of MMF.
Abstract: We report that the center-launching technique can be improved to selectively excite the fundamental mode of multimode fiber (MMF). This ldquomode-field matchedrdquo center-launching technique enables us to excite only the fundamental mode in the MMF and, consequently, avoid the inherent limitations imposed by the differential mode delay. We realize this mode-field matched center-launching technique simply by fusion-splicing a single-mode fiber (SMF) pigtailed transmitter to the MMF. The splicing condition is optimized to expand the core of SMF slightly so that it can match the mode field distribution of the fundamental mode of MMF. The results show that, by using this launching technique, we can achieve the transmission characteristics similar to SMF and drastically increase the bandwidth-distance product of MMF. For demonstrations, we have successfully transmitted 10- and 40-Gb/s signals over 12.2 and 3.7 km of MMF, respectively, without using any dispersion compensation techniques. We have also evaluated the robustness of the MMF link implemented by using the proposed launching technique against the mechanical perturbations such as the lateral offset between fiber connectors, fiber bending, and fiber shaking.
4 citations
01 Jul 2018
TL;DR: In this paper, an all-fiber method to determine the wavelengths at which a fabricated SMm device provides a single mode output is presented, which does not require measurement of the modal weights.
Abstract: We demonstrate an all-fiber method to determine the wavelengths at which a fabricated SMm device provides a single mode output. This method is quick and does not require measurement of the modal weights.
Cites background from "Wavelength sensitivity of the excit..."
...An error in fabricating the accurate length of MMF1 and/or an error in the fiber parameters degrades the device performance, which can be mitigated by changing the operating wavelength [2, 3]....
[...]
References
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TL;DR: In this article, an experimental and theoretical study of bandwidth enhancement in multimode fiber links achieved by using offset launch techniques is presented. But offset launch is not suitable for low bandwidth "worst case" fibers.
Abstract: This paper reports an experimental and theoretical study of bandwidth enhancement in multimode fiber links achieved by using offset launch techniques. It is found, both from theory and experiment, that an up to four-fold bandwidth enhancement can be obtained compared to standard overfilled launch techniques despite exciting over 50% of the fiber modes, thus allowing good stability. The enhancement technique is found to be achieved for a range of fibers with different core diameters and core refractive index profiles. The level of bandwidth enhancement depends upon the inherent bandwidth of the fiber, being particularly effective in improving the performance of low bandwidth "worst case" fibers. The launch is found to be stable with respect to environmental variations, showing bandwidth enhancement for injection positions or connector offsets of up to 5 /spl mu/m from optimum. In addition, unlike many restricted launch techniques, it is found to be tolerant to angular fiber misalignment for angles up to 6/spl deg/ from normal.
322 citations
"Wavelength sensitivity of the excit..." refers background in this paper
...Various authors have suggested different launching methods such as mode field matched centred launching [2]–[4] and offset launch technique [5] to improve the channel capacity of an MMF communication link....
[...]
TL;DR: In this article, a single-mode-multimode-single-mode fiber structure is investigated and a simple way to predict and analyze the spectral response of the structure is presented through the space to wavelength mapping with the derived approximated formulations.
Abstract: This paper presents an investigation on a single-mode-multimode-single-mode fiber structure. A one-way guided-mode propagation analysis for the circular symmetry waveguide is employed to model the light propagation and the approximated formulations are derived and evaluated concerning the accuracy. Phase conjunction of the multimode interference within the fiber structure is revealed. A simple way to predict and analyze the spectral response of the structure is presented through the space to wavelength mapping with the derived approximated formulations. The prediction of spectral response is verified numerically and experimentally.
277 citations
TL;DR: In this paper, the authors demonstrate mode-division multiplexed WDM transmission over 50 km of few-mode fiber using the fiber's LP01 and two degenerate LP11 modes.
Abstract: We demonstrate mode-division multiplexed WDM transmission over 50-km of few-mode fiber using the fiber’s LP01 and two degenerate LP11 modes. A few-mode EDFA is used to boost the power of the output signal before a few-mode coherent receiver. A 6×6 time-domain MIMO equalizer is used to recover the transmitted data. We also experimentally characterize the 50-km few-mode fiber and the few-mode EDFA.
261 citations
TL;DR: The theoretical background of MMF transmission is discussed and an overview on system characterization and existing standards are given and the challenges on reach, speed, and capacity-extension techniques for next generations ofMMF systems are discussed.
Abstract: High-speed transmission in multimode fibers (MMF) is becoming attractive for the realization of high-capacity transmission systems at low cost. This paper discusses the theoretical background of MMF transmission and gives an overview on system characterization and existing standards. The authors review latest achievements in component development for highest-speed MMF systems and discuss the challenges on reach, speed, and capacity-extension techniques for next generations of MMF systems.
138 citations
TL;DR: In this paper, the authors proposed a mode-field matched center-launching technique by fusion-splicing a single-mode fiber (SMF) pigtailed transmitter to the MMF, where the splicing condition is optimized to expand the core of SMF slightly so that it can match the mode field distribution of the fundamental mode of MMF.
Abstract: We report that the center-launching technique can be improved to selectively excite the fundamental mode of multimode fiber (MMF). This ldquomode-field matchedrdquo center-launching technique enables us to excite only the fundamental mode in the MMF and, consequently, avoid the inherent limitations imposed by the differential mode delay. We realize this mode-field matched center-launching technique simply by fusion-splicing a single-mode fiber (SMF) pigtailed transmitter to the MMF. The splicing condition is optimized to expand the core of SMF slightly so that it can match the mode field distribution of the fundamental mode of MMF. The results show that, by using this launching technique, we can achieve the transmission characteristics similar to SMF and drastically increase the bandwidth-distance product of MMF. For demonstrations, we have successfully transmitted 10- and 40-Gb/s signals over 12.2 and 3.7 km of MMF, respectively, without using any dispersion compensation techniques. We have also evaluated the robustness of the MMF link implemented by using the proposed launching technique against the mechanical perturbations such as the lateral offset between fiber connectors, fiber bending, and fiber shaking.
113 citations
"Wavelength sensitivity of the excit..." refers background in this paper
...Various authors have suggested different launching methods such as mode field matched centred launching [2]–[4] and offset launch technique [5] to improve the channel capacity of an MMF communication link....
[...]