Statistical properties of low-frequency fluctuations during single-mode operation in distributed-feedback lasers: Experiments and modeling

A single-mode distributed-feedback (DBF) laser with a large side-mode suppression ratio was investigated to fulfill the single-mode assumption of the Lang-Kobayashi (LK) model. A single-mode 1.55-μm DFB semiconductor laser was subjected to delayed optical feedback from an external cavity. The spectra were recorded with a grating spectrometer with a resolution of 0.1 nm. The significant linewidth broadening toward longer wavelength corresponded to predictions of the LK model.
This research was supported by the Deutscher Akademischer Ausfausddienst, Accion Integrada HA98-29, the Ministerio de Educacion yCultura of Spain, and the Deutsche Forschungsgemeinschaft Sonderforschungsbereich 185.