A new DBR laser structure for improved side-mode suppression

The authors propose and analyze a novel distributed Bragg reflector (DBR) laser structure that exhibits superior side-mode suppression when compared to the well-known DBR laser. This is achieved by introducing a strong symmetry in the reflectivity of the DBR section and results in a high (>36 dB) and ideally constant side-mode suppression ratio as the laser is tuned. This asymmetry in reflectivity can be achieved by nonlinearly chirping the local spatial frequency of a regular (periodic) Bragg grating.>