The action is to enhance or improve the design of green laser pointer

Therefore, the need to develop a new multi-mode fiber, an 850nm laser-optimized fiber. Even with this new fiber, another RML bandwidth test methods can not completely guarantee the 10Gbit / s, 300 m of transmission. To meet the requirements on the transmission speed and transmission distance, it is only the mode of the fiber dispersion to reduce to an unprecedented level, which requires more fundamental measurement mode dispersion. TIA and IEC regulations, for laser-optimized fiber DMD measurements, and each DMD must meet very stringent requirements. Measurement of DMD in the end what is it? It is for the manufacturer to integrate with the existing technology of green laser pointer .
There is a explained that it is similar to the pulse delay dispersion measurement (time domain). But in fact the pulse transmission delay is not measured as a function of wavelength to the transmission delay of the laser pulse is measured as a function of radial position, this position pulse is injected into the multimode fiber core location. Figure 1 a simple explanation of the time-domain DMD measurement. A probe light pulse injected into four different radial position of the optical fiber from the fiber injection and at different times, this is because the excitation mode transmission characteristics of the group in different locations will be different. Then the relative time difference between the fastest and slowest pulse fiber DMD. It is the aluminum material of green laser pointer .
Whether the determination of the DMD of each fiber depends on the fiber manufacturer. At this point, DMD merely as an internal process control parameters, because in the commercial side, it is not spectral attenuation or bandwidth of optical fiber characteristics as clearly, so there is no international standard test procedures for the DMD, but also does not have any practice to regulate it. Therefore, the optical fiber manufacturing commercial to measure the DMD and the way of the results in general there are multiple. Despite this variability, but in fact all of the time-domain DMD measurement are the following: the test, the output of the pulsed laser spot is aligned with the center of the fiber core. It is to integrate the imported technology with the existing technology of green laser pointer .
Receiving the light pulses in optical fiber, the output pulse amplitude is a function of time to record a high-speed detector and sampling oscilloscope. The laser spot through the fiber core at each measurement point record of the same magnitude and time information. Use some kind of pulse positioning technology to determine the relative delay of the radial pulse. A compensation for a good (low DMD) fiber DMD measurement results shown in Figure 2 is similar. Please note that in this case circles and dashed lines correspond to the DMD data set the fastest rising and slowest falling edge. Higher accuracy and resolution. With the new 850nm laser optimized for the 10GbE 50mm fiber available. This kind of   laser pointer is made of the aluminum.