Multiwavelength grating reflectors for widely tunable laser

We propose a new reflector approach in order to get the reflectivity comb needed in widely tunable lasers. This reflector is realized by holographic exposure of superimposed multiple Bragg gratings. It provides efficient reflectivity with short guide sections (150 μm) leading to improved static laser characteristics. This reflector has been successfully included in 20-nm tuning DBR lasers.