Design and Development of a Dual-Core Erbium Doped Amplifier for Polarization-multiplexed Signals

The extensive usage of Erbium Doped Fiber Amplifier (EDFA) in fiber optic networks creates many new configurations and technologies. Conventional optical amplifiers based on EDFA can amplify multiple channels at the same time, but within a single fiber optic core. The amplifier can be made to support multiple fibers, however the channels must be at different set of wavelengths, which is impractical since optical channels are standardized at a specific set of wavelengths. Therefore, the application of optical amplifiers are limited for one fiber core only. As an alternative, a design of an EDFA is hereby proposed. With this amplifier, it will make the network management simpler. It also provides flexibility in optical network design. In this dissertation, the design and development of EDFA is detailed and discussed. The design has made it possible to support two fibers with each one carrying the same set of wavelengths. This is achieved by taking advantage the polarization multiplexing techniques which allow a combination of lights by setting them linear and orthogonally apart. The signals co-exist in a single core EDF by differentiating both of their polarity using polarization controllers. Then it will combine through in a single core using a 3dB coupler. The combined signals are then amplified by the EDFA simultaneously, doubling the amount of signals carried by the same wavelength. The amplifier has been successfully tested at the transmission speed as high as 2.5Gbps. Moderate gain and noise figure of the EDFA was achieved at an optimum pump power for the EDF at 40mW. The transmission performance also shows tolerable polarization crosstalk due to unpolarized amplified spontaneous emission with the bit error rate showing little difference compared to that of the conventional amplifier. The results were obtained mainly through experimentation while others are through software simulation.