Figure 2
From: Measurement of the emission spectrum of a semiconductor laser using laser-feedback interferometry
Interferograms recorded via the laser terminal voltage VLFI with the laser operating on (a) single and (b) multiple longitudinal cavity modes. Voltage signals have been amplified by a 22 dB differential amplifier. (c) and (d) show the respective emission spectra obtained by performing a fast Fourier transform of the complete interferograms corresponding to data presented in (a) and (b).
