Spectrally resolved analysis of fast tuning in single-mode pulses generated from mutually injection-seeded Fabry-Perot laser diodes

Electrically wavelength-tunable pulses are generated from two mutually injection-seeded Fabry-Perot laser diodes at 1 GHz. By investigating the spectral dynamics, we experimentally show that stable single-mode output can be obtained after four roundtrip propagation cycles in the external cavity. We also probe the dynamic change of the spectrum during the switching between two single-mode wavelengths. It is found that the steady states can be reached after six to seven roundtrip cycles.