Gain measurement of semiconductor optical amplifier by cavity ring-down spectroscopy technique
A novel method to measure the gain of semiconductor optical amplifier(SOA)by cavity ring-down spectroscopy(CRDS)technique is proposed and experimentally demonstrated.The experimental system consists of a DFB laser modulated by RF signal,a SOA,a circulator,a fiber Bragg grating,two couplers,a temperature controller,a photo detector,and an oscilloscope.The function relationship between the gain of SOA and the cavity ring-down time is derived.The results showed that the cavity ring-down time is a function of SOA gain,which is a function of wavelength.Provides a new method for measuring SOA gain and the technical feasibility.