This paper demonstrated a multiwavelength fibre laser incorporating semiconductor optical amplifier in nonlinear optical loop mirror with polarisation maintaining fibre. The configuration comprised 3-dB optical coupler, semiconductor optical amplifier, and a 2-meter length of polarisation maintaining fibre. The range of semiconductor optical amplifier varied from 160mA to 180mA to determine and evaluate their performance in terms of peak power and stability. Based on the results, the power fluctuation for different wavelengths at 1555nm, 1558nm and 1561nm was less than 5dB. In addition, the output peak power increased as the semiconductor optical amplifier current increased. The highest output peak power was - 2.093dBm at 180mA with lasing wavelength of 1558nm. The stability test showed that the multiwavelength fibre laser system was stable at room temperature within 60 minutes. Furthermore, the polarisation maintaining fibre that acts as gain medium has a broader bandwidth operating in the C-band to L-band at room temperature.