Tandem active layer superluminescent diode with a very wide spectrum

Broader spectral width superluminescent diodes having a new structure of tandem active layers are proposed and fabricated at a 1.3 μm wavelength. The emission spectral widths were successfully broadened over 100 nm, thus achieving a very short coherence length of less than 10 μm. Applying this new active layer structure to a Fabry–Perot cavity, a unique function of superluminescent/laser mode switching is also demonstrated.