Low-Loss Hand-Made Demultiplexer using Transparent Color Filter in WDM-POF Network for Short-Haul Communication System

Abstract

Problem statement: Polymer optical fiber has advantages compared to other alternatives communication media such as copper, coax cable and glass fiber. POF has bigger bandwidth compared to wireless communication network and POF is also free from electromagnetic disruption. Since POF is suitable for communication system up to distance of 100 m with data speed of 400 Mbps using polymer step-index type, therefore, POF is effective for short haul data transmission. Application of POF includes the Ethernet network at home or usually known as Fiber To The Home (FTTH) and in also used in automotive system. However, since the demand of high capacity of the transmission system, wavelength division multiplexing technique or WDM is applied in this study. Approach: Several signals with different wavelengths are multiplexed and carried over a single fiber and demultiplexed at the end of the communication system to obtain the original signal to be directed to the receiver. The advantage of the device developed in this study is that it is easy to construct and inexpensive. Thin-film is used as filter and three main color wavelength used are red, blue and green thin-films. The red thin-film will absorb any other wavelength other than λ = 650 nm, blue thin-film will absorb any other wavelength other than λ = 475 nm while the green thin-film will absorb any other wavelength that is not around λ = 510 nm. Characterization is done to test the signal loss through each of the thin-film. Low-loss filter for the wavelength of the desired signal is analyzed to get the best thin-film that gives optimum transmission while blocking other undesired wavelengths. Insertion loss and power output are measured to determine the thin-film to develop the demultiplexer that work effectively. In this study, the distance of the optical fiber is not taken into account, however, the length of the optical fiber is set to be 5 m each. Results: Although there exists attenuation of signal transmission along the fiber and at the transparent colored thin-film, the demultiplexer works efficiently for short haul communication system with small loss of power output and small increase of insertion loss for the desired wavelength transmitted. Conclusion: Analysis shows that the device works efficiently for short distance communication although the results show insignificant signal loss along the transmission.