Dynamical noise in single-mode distributed feedback fiber lasers

The dynamics of erbium distributed feedback fiber lasers close to steady state is analyzed taking into account spatial hole burning and the nonuniform modefield distribution. A set of linearized equations is derived and used to obtain theoretical amplitude and frequency noise spectra for spontaneous emission noise and generic pump power noise. Analytic formula for important laser characteristics including pump slope efficiency and relaxation oscillation frequency are also obtained. It is found that the spatial distribution of the laser mode plays and important role in determining the output characteristics of the laser.