Optical fiber has been used to fulfil the increasing need of high speed and high capacity data transfer. With 4.3 million users and 18.3% growth projection per year, fixed broadband sector of PT Telkom Indonesia relies on the quality of fiber optic backbone infrastructure, which represented by the Signal to Noise Ratio (SNR) and Bit Error Rate (BER). So, it is necessary to analyze SNR and BER parameters of fiber optic backbone in the segment between STO Lamongan 1 and STO Kebalen, Surabaya. SNR is logarithmic ratio of received signal and noise power, while BER is the measure of incorrect bit identification probability. The measurement process taken in STO Kebalen`s receiver by connecting BER Tester into one of the DWDM ports in Optical Transport Network (OTN) platform for 24 hours. It showed the result of BER 10-23. To better analyze SNR and BER parameters completely, it needs a simulation brought by Optisystem software. The 100 Gbps, 84 km, 10 channels DWDM backbone is simulated in 193.1-194 THz with 100 GHz of frequency spacing. Parameters of the simulation are following the characteristic of the backbone itself and components datasheets. WDM analyzer and BER analyzer are used as measurement instrument. The simulation shows that SNR and BER of the system is acceptable based on standards and different at each frequency or wavelength channel. Maximum SNR is 72.37 at 193.6 THz, while minimum BER reaches 2.05 × 10-30 at 193.5 THz. To obtain the optimum BER of 10-12, two kinds of treatment, dispersion compensating fiber installation and transmitter power addition on 193.1, 193.2, 193.9, and 194 THz are simulated.
People with visual disability unable to recognize the nominal of banknotes in conducting economic life, hence, rely on their touch and hear senses to recognize the banknotes. In this work, we investigated the LDR sensor to detect the nominal value of banknotes with voice output. It was found that the error rate 100% for IDR 2000, IDR 10000, IDR 100000, and IDR 50000, 75% error rate was for IDR 5000 and IDR 2000, and 50% error rate for IDR 1000.
LASIK (Laser Asissted In Situ Interlamelar Keratomilieusis) is a technique for correcting refractive disorders of the eye such as myopia and astigmatism using an excimer laser. This procedure use photoablation technique to decompose corneal tissues. Although preferred due to its efficiency, permanency, and accuracy, the inappropriate amount radiant exposure often cause side effects like under-over correction, irregular astigmatism and problems on surrounding tissues. In this study, the radiant exposure effect toward corneal ablation volume has been modelled through several processes. Data collecting results is laser data specifications with 193 nm wavelength, beam diameter of 0.065 - 0.65 cm, and fluence of 160 mJ/cm2. For the medical data, the myopia-astigmatism value, cornea size, corneal ablation thickness, and flap data are taken. The first modelling step is determining the laser diameter between 0.065 - 0.65 cm with 0.45 cm increment. The energy, power, and intensity of laser determined from laser beam area. Number of pulse and total energy is calculated before the radiant exposure of laser is obtained. Next is to determine the parameters influence the ablation volume. Regression method used to create the equation, and then the spot size is substituted to the model. The validation used is statistic correlation method to both experimental data and theory. By the model created, it is expected that any potential complications can be prevented during LASIK procedures. The recommendations can give the users clearer picture to determine the appropriate amount of radiant exposure with the corneal ablation volume necessary.
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