Determination of Internal Loss and Quasi-Fermi Level Separation From the Amplified Spontaneous Emission Spectrum of Fabry–PÉrot Semiconductor Lasers

The net modal gain and the un-amplified spontaneous emission (ASE) coupled into the laser waveguide mode are extracted from the ASE spectrum of Fabry-Perot semiconductor lasers by the Fourier transform method with a deconvolution process. Highly accurate quasi-Fermi level separation and internal loss are then derived by a minimum search process from the relationship between the spontaneous emission and gain