Semiconductor laser amplifier (SLA) based technology is an enabling technology for advanced optical networks. The potential for large-scale integration of SLA technology offers economical, high-performance devices that combine monolithic and hybrid solutions. Using SLAs, various devices can be built with enhanced functionalities as required for future optical networks. In a SLA, amplification of incident optical radiation takes place in the active layer along the length of an amplifier. However, frequency response of input signal (which can be amplified by a SLA), depends upon the available bandwidth. In this paper, a new analytical technique is outlined for bandwidth measurement of a SLA. This technique is based on measurement of saturation power and input power coupled in the active layer of SLA and is successfully applied to calculate the bandwidth of FP and near traveling wave (NTW) SLAs.