12.5-gb/s direct Modulation up to 115(degree)C in 1.3-(mu)m InGaAlAs-MQW RWG DFB lasers with notchfree grating structure

Direct modulation at 12.5 Gb/s of 1.3-(mu)m InGaAlAs distributed feedback (DFB) ridge waveguide (RWG) lasers with low-resistance notch-free gratings running up to 115(degree)C is experimentally demonstrated. It was achieved by the combination of the high differential gain of an InGaAlAs MQW active layer, high characteristic temperature of RWG structure, and low-resistance notch-free grating. Moreover, successful transmission of 10-Gb/s modulated signals over 30-km standard single-mode fiber was achieved with the laser running at up to 115(degree)C. These results confirm the suitability of this type of laser for use as the cost-effective light source in 12.5-Gb/s and 10-Gb/s datacom applications.