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.