Détection d'un point de blocage dans un câble à fibre optique. 
Détecter un point de blocage dans un câble à fibre optique est essentiel pour les réseaux à fibre optique. Cet article vous expliquera comment effectuer de tels tests à l'aide des techniques Brillouin, Raman et OTDR. Vous pourrez ensuite déterminer si votre câble est effectivement bloqué. Si c'est le cas, vous devez suivre ces conseils pour vous assurer que votre câble n'est pas obstrué. Nous espérons que cet article vous sera utile.
 
OTDR
One way to use the OTDR to detect a blockage point in a fiber optic cable is to use it on a mechanical splice. The splice will create a reflection peak on the OTDR screen, which will tell you how much reflection is created at the connection. Typically, this peak will be flat at the far end and have a tail at the top. If this is the case, the fiber has been overloaded.
 
Une autre façon de déterminer s'il y a un point de blockage in a fiber est de comparer les traces OTDR à la documentation d'installation. Si les traces correspondent, alors la section épissée est en bon état. Dans le cas contraire, il est possible que l'épissure soit à l'origine de la rupture. Un OTDR haute résolution aura une perte mesurée plus faible et un affichage haute résolution.
 
A common mistake people make when using an OTDR is to assume that it can measure cable loss. This is not the case. Many international standards do not allow OTDRs to measure cable loss. OTDR is required. If you use OTDR to detect a blockage point, be sure to use a power meter and source. Also keep in mind that ghosting can occur if the fiber has a highly reflective connector.
 
FWHP
In optical communications, FWHP is the method of measuring the width of the spectral emission at 50 % from full amplitude. This technique is also called full-width half-power (FWHP) and is a widely used test method for fiber optic systems. FWHP is used to detect blockage points in fiber optic cables. In order to identify these points, a fiber must be properly measured.
 
Raman
La méthode Raman a récemment été appliquée aux fibres. Le point de fiber blocking est la région où un seul photon a plus d'une longueur d'onde. En pratique, cela signifie que la détection d'un point de blocage est possible pour une fibre de petit diamètre. Un développement ultérieur de cette méthode lui permettra de détecter les blocages dans les fibres de grand diamètre.
 
Researchers at HORIBA Scientific in northern France have developed a Raman method for identifying the blockage point of a fiber. The technique uses high-powered computers, air-cooled lasers and multichannel detectors. The technique can be used on a wide range of samples, including solids. It can detect blockages in a fiber, as well as the smallest features of a fiber.
 
The Raman technique has a number of advantages over other techniques. The instrument used for the experiments is portable and has an array of components. For example, it is capable of detecting blockages in fibers several hundred micrometers in diameter. In addition, the method is also useful for large and curved fibers, as it allows accurate measurement of the smallest details of the fiber.
 
Brillouin
The Brillouin method of detecting spliced fibers uses the phenomenon of the Brillouin gain spectrum at high frequency. It can detect blockages down to the size of a fiber strand. This technique has some limitations. The resulting noise is often too high to use the technique to detect spliced fibers. A higher sampling rate is required for the Brillouin method.
 
The easiest way to detect a blockage point is to use the Slope-Assisted Brillouin Sensor. The principle of slope-assisted Brillouin sensors is similar to the BGS engineering technique. This technique requires access to the fiber at two ends and can be used in fiber optic networks. The sensors are available in commercially available kits.
 
Le présent mode de réalisation comprend une pluralité de premières valeurs intégrées. La lumière de sonde L1 et la lumière de pompe L2 sont utilisées pour générer une première valeur intégrée. La deuxième valeur intégrée est ensuite calculée sur la base de la lumière de diffusion Brillouin stimulée. Il est important de noter que la bande noire de la fibre interfère avec ce signal. Cette lumière n'est pas projetée hors de la optical fiber of FUT measurement.
 
Meters of optical power
The accuracy of optical power meters depends on the measurement range. The measurement range of an FOPM is between three and 10 dB above the noise floor. At the low end, this error is about 10 %, while the highest value is 0.4 dB. For high-resolution measurements, an optical power meter must be calibrated at each range, but the uncertainty can be higher.
 
The calibration method used is described in FIG. 2. Other details of the calculation can be devised by a person skilled in the art. The optical power offset values are read when the amplification gain setting is greater than two. It is then necessary to calibrate the meter at the reference and measurement temperature points to verify the accuracy of the measurements. The meter is not accurate when the temperature is outside this range.
 
The counter includes a photodetector 12 and a data storage unit 20. The photodetector may be any p-n junction, low capacitance planar diffusion, Schottky, or PIN photodiode. The data can be input to a processor for analysis. It is possible to set the meter to read the power of a signal using a single measurement.
 
Optical time domain reflectometer
Optical time domain reflectometers are optoelectronic instruments used to characterize fibers. They work by injecting a series of optical pulses into the fiber and determining the reflected and scattered light. The reflected light is similar to the signal generated by an electronic time domain meter, which measures impedance changes.
 
Pour détecter le point de fiber blocking, un OTDR doit mesurer la lumière pulsée qui est renvoyée par la fibre optique cible de la mesure 71. La lumière pulsée doit arriver de manière fiable à la première zone de réception de lumière 191 a, où elle est convergée par une lentille 170. Les signaux résultants de plusieurs mesures sont ensuite moyennés au niveau de l'unité de traitement du signal 40.
 
The spectral response of the optical time domain reflectometer is determined by the ratio of the pump and probe beam fields. In this configuration, the probe beam field is confined by a factor of two and the pump beam. Depending on the relative power ratio of the pump and probe beams, the probe wave is amplified and propagates back to the photodetector, where the time evolution of its intensity is detected.
 
Post-mortem studies of the hard carbon half-cell
Conventional full-cell and half-cell tests tend to underestimate the capacitance loss or cyclability of hard carbon. A recent study of hard carbon sp2 nanodomains showed that they can maintain their disorder and cyclability at 3000°C, without graphitization. This study provides a new approach to evaluate the capacitance and cyclability of the hard carbon anode.
 
The results from Ji's group confirmed the polarization effect of hard carbon. U OCVhard carbon has an open circuit voltage that is consistently greater than 0 V compared to Na+/NaBCC. NaBCC does not precipitate in THT half-cell tests. In addition, polarization becomes more evident at higher current density. These results suggest that the rate capability of hard carbon is underestimated.
 
Although SIBs were developed a decade after LIBs, the investigation of these cells did not gain much traction until the last decade. This review of hard carbon half-cells provides a comprehensive overview and addresses issues that have often been overlooked, such as the CE cycle life relationship and underestimated reversible capacity. The review also highlights the use of a metal counter electrode that has a much higher reactivity and impedance than LiBCCs. The revised half-cell test method provides a full reference capacitance as well as the true hard carbon capacitance.