## 4 Bandwidth  
During the next step, we performed DMD map measurement of manufactured 520 m pilot length of LOMF 100/125 by DMD analyzer workstation lab kit R2D2 [20; 21], according to ratified standards TIA-455-220-A/FOTP-220 and IEC 60793-2-10, concerned with laser-excited optical pulse response measurements at the tested MMF receiving end under precision offset launching conditions. Simplified block-scheme of the experimental setup for DMD map measurement under control of launching conditions is shown on Figure 9; workstation and software R2D2 screenshot are shown on Figures 10 and 11. The Fabry-Perot LD \"2\" generates quasi-Gaussian optical pulse at wavelength \(\lambda\) = 1310 nm with width at a half maximum (FWHM) about 340 ps. It is pigtailed by standard single-mode (SM) optical fiber ITU-T Rec. G.652 terminated by FC/PC connector \"3\". Emission from the LD output is launched to MMF via single-mode pigtail (ITU-T Rec. G.652) \"5\", which is spliced with tested MMF under precision offset by fusion splicer via program \"Attenuator\". Here parameter \"Attenuation\" is set to 0, \"offset\"--to particular value, and \"ECF factor\" (surface tension compensation factor) also is set to 0 to avoid deformations in the heat zone of the offset fusion splice. Measured spectrum of DMD analyzer laser source is shown on Figure 12. Reference optical signal (measured via short SM patch-cord) with overlapped Gaussian pulse is represented on Figure 13.  
Results of DMD map measurement with 1.0 \(\upmu\)m interval of the offset launching over range 0 \(\ldots\) 25.0 \(\upmu\)m are represented on Figure 14. Here, optical pulse keeps its envelope without any DMD distortions over all the researched offset ranges up to 25 \(\upmu\)m misalignment under corresponding spreading that also demonstrate potential survivability of developed LOMF 100/125 to the launching conditions. Figure 12: Optical spectrum of DMD analyzer Fabry–Perot LD. Figure 13: Reference optical pulse. Therefore, during the next stage, we performed estimation of pulse dispersion in relation to initial its FWHM 340 ps by the well-known method for signal with arbitrary form spreading estimation (for example, it is described in details in the textbook [22]). Results of dispersion evaluation are shown on Figure 15. The minimal dispersion (150...175 ps) corresponds not to only centralized and low offset launching conditions, but also, it is achieved under the great radial misalignment between cores of matching SM and tested LOMF 100/125 optical fibers with value up to 10 \(\upmu\)m. We computed approximate acceptable values of dispersion for 1000 Base-LX and 10 GBase-LX specifications and 520 m MMF link by \"the worst case\" link model, developed by IEEE 802.3z Task Force for the first time, declared and ratified ability of laser based data transmission over MMFs with 1 Gbps bit rate [23; 24], by taking into account typical transceiver power budget parameters [25]. As a result, the maximal measured pulse dispersion corresponds to offset 25 \(\upmu\)m, and it is not more than 300 ps, while estimated acceptable values for 1000 Base-LX and 10 GBase-LX specifications for 520 m MMF link are 874.5 ps and 87.1 ps, respectively, which demonstrates good bandwidth potentiality of proposed designed and manufactured LOMF 100/125 for applications on the short range onboard and industrial multi-Gigabit network cable systems. Figure 14: LOMF 100/125 DMD map at wavelength \(\lambda\) = 1310 nm under the reference Gaussian pulse FWHM = 340 ps over 0 \(\dots\) 25.0 \(\upmu\)m offset range via 1.0 \(\upmu\)m interval. Figure 15: Results of dispersion evaluation. Finally, during the next stage, we directly measured bit error rate (BER) of IEEE 802.3z 1000 Base-LX data transmission channel over 520 m link with presented LOMF 100/125 by certified interface analyzer.