Design and analyses of BER performance in a tri-directional optical transmission system

Abstract

The aim of the paper is to verify the stability of the tri-directional fiber transmission system. The design of transmission methods is different wavelengths modulated in the electrical signal of 10 Gbit/s and 2.5 Gbit/s based on the corresponding architectures. The goals are to measure the influence of the signal with the same and adjacent channel interference. The experimental architecture is designed in parallel. We chose the wavelength of 1552.5 nm as the receiving signal to keep the scheme working in the same conditions for comparison. In addition, we insert an additional 25 km and 50 km single-mode fiber (SMF). The result shows that power penalty can be improved within a range of 2–3 dB if a bandpass filter (BPF) is inserted before the measurement equipment. The standard in the experiment requires a wavelength spacing of 0.8 nm between each channel. The result shows that in transmission methods with different wavelengths and distances, the power penalties are 0.304 dB, 0.595 dB, and 1.173 dB, respectively. As the transmission speed decreases with different distances of 0 km, 25 km, and 50 km, the power penalties are 0.101 dB, 0.385 dB, and 0.538 dB, respectively. With the hybrid speed under different distances, the power penalties are 0.278 dB, 0.404 dB, and 0.551 dB. The tri-directional transmission can be divided into with or without an optical switch connection, while the function of the optical switch is to divide the system into the cross and parallel switching modes. According to experimental results, the power loss is in a range of 2–4 dB, and the power reimbursement is slightly increased by 0.1–0.2 dB. To compare the results with the worst condition, the power penalties for no optical switch (OSW), OSW in bar state, and OSW in cross state are 0.756 dB, 0.317 dB, and 0.329 dB, respectively.