Measurement of baseband frequency response of multimode fibre by using a new type of mode scrambler

On the mode-dependent loss compensation for mode-division multiplexed systems

“…Mode coupling arises from mechanical perturbations or from waveguide imperfections [15]. Mode scramblers have been focus of research in the past years [16][17]. Since the multi-mode fiber bandwidth is largely dependent on the input power, the purpose of such devices is to achieve a uniform power pattern after the light source and hence, ensure the reproducibility of the bandwidth measurements.…”

“…In Fig. 3(a), two examples of possible mode scramblers are depicted: fiber grating [7] and serpentine bends [16]. The former applies pressure on the fiber, which has to be optimized together with the angle from which the pressure is applied.…”

“…The latter employs bends through cylindrical structures, whose quantity, separation and radius have to be optimized. In these simulations, the mode scrambler was modeled as a 12-cm FMF fiber (fiber length used in [16]), where mode coupling is introduced every 500 μm (resembles the nominal grating pitch in [7]). The mode scramblers were placed as indicated in the inset FMF channel (b) in Fig.…”

Mode control for emerging link performance standards

“…A variety of mode-scrambling techniques has been described in the literature, such as sinusoidal bending [5], devitrification [6] and microbending [7], applied to step-index fibres, and Long Period Gratings (LPGs) [8], etched fibre ends [9], and offset launch [10], applied to graded-index fibres. In the case of a step-index mode-scrambler it is necessary to provide some additional mode-filtering in the target graded-index fibre to achieve the required modal filling.…”

Optical time-domain reflectometer performance and calibration studies

“…Most of these mode filters operate on the principle of selectively removing power in the higher-order modes through radiation from macrobends of some sort. Examples are serpentine bend or S-shaped channel types [40], and the linear array of pegs [50]. The mandrel wrap structure is another widely used mode filter that was originally developed at the Bell Telephone Laboratories.…”