Multiwavelength fiber laser based on different types of semiconductor optical amplifiers

Abstract

Communication system in optical fiber technology has emerged as a demanding field especially for the new dense wavelength-division multiplexed (DWDM) system wherein many functional applications and basic laser system are included. The generation of multiple laser lines in multiwavelength fiber laser (MWFL) is significant in semiconductor optical amplifier (SOA) device utilization as a medium of gain to achieve a flat laser spectrum. Apart from Erbium-doped fiber amplifier (EDFA) and Raman amplification that have high mode competition and high pumping power respectively, MWFL configuration has delegated SOA due to its special inhomogeneous characteristic as a device of stability compared to other devices of scattering and amplification effects. An investigation on the types of different wideband travelling wave (TW) SOA with parameters such as optical gain, output power, noise figure (NF) and amplified spontaneous emission (ASE) noise and bias current was carried out through OptiSystem and MATLAB software and then verified by benchtop experiments. Linear SOA had the most flat gain with low NF and ASE pattern at input power -30 dBm compared with nonlinear SOA. A practical Lyot-combed and fiber Bragg grating (FBG) were constructed using unidirectional single cavity in different types of SOA and linear SOA displayed the flattest peak powers. Multiwavelength spectrum from linear, nonlinear SOA and booster optical amplifier (BOA) were varied by intensity, polarization angle (PA), in-line polarizer and time stability by applying performance evaluator such as the number of laser lines, extinction ratio (ER), channel spacing and highest optical power. The laser experiment for linear SOA concluded with the flattest spectrum in time stability which was true to the characterization modelling result and it also acted differently as nonlinear SOA and BOA that vary greatly to nonlinearity with different PA.