Topic
Mode scrambler
About: Mode scrambler is a research topic. Over the lifetime, 896 publications have been published within this topic receiving 13595 citations.
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29 Sep 2004
TL;DR: In this article, the authors describe the transformation of the propagation mode of optical signals into a dissipative cladding mode in order to prevent or limit the propagation of the signals in the first guided mode while at the same time authorising the second guided mode in the multimode fibre.
Abstract: An optical device (D) is dedicated to the transformation of the propagation mode of optical signals. This device comprises at least a first mode converter (3) that is supplied with signals that are propagated in a first guided mode and that delivers the signals in a multimode fibre (4) partly in the first guided mode and partly in a second guided more of a higher order that the first. The multimode fibre (4) comprises at least first passive filtering means (R) which have the task of converting the first guided mode into at least one dissipative cladding mode in order to prevent or limit the propagation of the signals in this first guided mode while at the same time authorising the propagation of the signals having the second guided mode in the multimode fibre (4).
7 citations
TL;DR: It was observed that mode mixing effects became more noticeable as the mode coupling coefficients increased, and it was found that the excess loss caused by microbends was relatively small.
Abstract: Mode coupling coefficients were measured in a multimode step-index fiber at different steps of the process of manufacturing a multistrand optical fiber cable. It was established that the mode coupling coefficients of the unsheathed fiber were relatively small and nearly the same for all the guided modes. By sheathing with nylon and by multistranding, the mode coupling coefficients between lower-order modes increased rapidly due to microbends, while in the vicinity of the highest-order mode, they remained unchanged. From impulse response waveforms and baseband frequency responses, it was observed that mode mixing effects became more noticeable as the mode coupling coefficients increased. Also, it was found that the excess loss caused by microbends was relatively small.
7 citations
TL;DR: This paper theoretically analyze the loss and branching ratio of multimode optical branching waveguides by using a ray tracing method to obtain less mode-dependent branching characteristics and finds that an optimum length to achieve a low loss and stable branching ratio exists.
Abstract: In this paper, we theoretically analyze the loss and branching ratio of multimode optical branching waveguides by using a ray tracing method to obtain less mode-dependent branching characteristics. First, a 2 × 2 optical mixing and branching waveguide with a step-index profile are considered. It is found that an optimum length to achieve a low loss and stable branching ratio exists. Second, a waveguide with mode scrambler is investigated. By sacrificing some amount of insertion loss, the mode dependence can be minimized.
7 citations
TL;DR: In this paper, a chirped broadband coupler is isolated from the narrow-band core mode coupler by an acoustic absorber to limit the acoustic interaction between them, and selected optical bands of wavelengths are re-coupled back into the core of the optical fiber.
Abstract: Device whereby one or more bands of optical wavelengths may be selected for further transmission. All light within the optical bandwidth of operation is first coupled from the core mode of an optical fiber to a specific cladding mode by a chirped broadband cladding mode coupler. These cladding mode lightwaves then enter a narrow-band core mode coupler whereby selected optical bands of wavelengths, tuned by the tension on the optical fiber, are re-coupled back into the core of the optical fiber. The chirped broadband cladding mode coupler is isolated from the narrow-band core mode coupler by an acoustic absorber to limit the acoustic interaction between them.
7 citations
TL;DR: In this article, a high-order mode dispersion compensating (HOM-DCM) was used to transform the LP01 mode of SMF fibers to the LP02 mode of specially designed dispersion compensating HOMF, with typical insertion loss of ∼ 1 dB, and typical extinction ratio to other modes less than -20 dB.
Abstract: High-Order Mode Dispersion Compensating Modules (HOM-DCM) using spatial optical transformations for mode conversion are reviewed. It is shown that mode transformers using this technology can be designed to transform the LP01 mode of SMF fibers to the LP02 mode of specially designed dispersion compensating High-Order Mode Fiber (HOMF), with typical insertion loss of ∼1 dB, and typical extinction ratio to other modes less than -20 dB. The HOMF itself can provide high negative dispersion [typically in the range of 400-600 ps/(nm km)], and high negative dispersion slope, allowing efficient compensation of all types of transmission fiber. Combining two mode transformers with HOMF and possibly trim fiber for fine-tuning, results, for example, in a HOM-DCM that compensates 100 km LEAF® fiber, with Insertion loss < 3.5 dB, and Multi-Path Interference (MPI) < -36 dB. MPI phenomena in HOM-DCMs is characterized, and shown to comprise both coherent and incoherent parts, and to result from both the mode transformers and fiber coupling within the HOMF. MPI values of < -36 dB have been shown to allow error free transmission of 10 Gb/s signals over up to 6000 km. Finally, a number of applications well suited to the properties of HOM-DCMs are reviewed.
7 citations