The noise and mode-locking phenomena of a hybrid soliton pulse source (HSPS)
utilizing different fiber Bragg gratings (FBG) with or without linear chirp
are described. The HSPS is modeled by a time-domain solution of the
coupled-mode equations including spontaneous emission noise, and relative
intensity noise (RIN) is calculated using numerical solutions of these
equations. It is found that transform-limited pulses over a wide tuning
range around the fundamental mode-locking frequency are generated from
mode-locked HSPS with linearly chirped uniform and Gaussian apodized FBGs.
Mode-locked pulses that are not transform-limited are generated over a wide
tuning range from HSPS with Gaussian apodized and uniform FBGs. These
gratings can give transform-limited pulses only over a limited tuning range
around the fundamental mode-locking frequency. It is also found that RIN
reduction is possible for the mode-locked HSPS by selecting a suitable
apodization function such as Gaussian and linear chirp rate.