Simultaneous dual-wavelength operation in cascaded strongly gain-coupled DFB lasers

Using cascaded strongly gain-coupled (SGC) DFB lasers, simultaneous dual-wavelength operation can be obtained with better than a 40-dB side-mode suppression ratio (SMSR) under simple operating conditions at various temperatures. Dual-wavelength operation with various spacing can be achieved by grating fabrication and by simply activating the lasing section of the cascaded SGC DFB lasers. The lasing wavelengths can be tuned within several nanometers by base temperature variation and their spacing can be fine tuned by individual injection current.