Analysis of wavelength conversion using a multisection DBR laser with a saturable absorber

The static performance of a wavelength converter obtained by a multisection distributed Bragg reflector (DBR) laser with a saturable absorber between two gain sections is analyzed. For this device an optical input signal at one given wavelength is converted into an output signal at the lasing wavelength. The performances are evaluated in terms of conversion efficiency, suppression ratio, and minimum input power needed for wavelength conversion. It is shown that a proper choice of the injected signal wavelength with respect to the lasing wavelength enhances the conversion efficiency and the suppression ratio and reduces the switching power. The performance can be enhanced also by increasing the electrical current applied to the first gain section provided that the second gain section is biased above the transparency level. The authors have shown that reduction of the front facet reflectivity results in a dramatic increase for the conversion efficiency. The sensitivity to the electrical bias condition and to the resonant condition of the injected signal with respect to the cavity has also been investigated