High Power and High Efficiency Operation of Semiconductor Optical Amplifier Assisted Extended Reach Electroabsorption Modulated DFB Laser (AXEL) for Extension of Transmission Distance

We have designed a semiconductor optical amplifier integrated with an electroabsorption modulator integrated distributed feedback laser (EML).We call this device AXEL; it is designed to enhance the power conversion efficiency and modulated light output power of EMLs.In this study, we investigated AXELs for both the L-band and O-band wavelength ranges.The results of experiments indicated that dramatically increased power conversion efficiency and modulated light output power were obtained with the fabricated AXELs.For the L-band wavelength range AXEL, a high modulated light output power of 9 dBm and an extension of 10-Gbit/s transmission distance to 80 km due to low chirp characteristics of the AXEL were simultaneously demonstrated.In addition, the 25-Gbit/s 80-km transmission achieved using the O-band wavelength range AXEL along with an avalanche photodiode was demonstrated for the first time thanks to the significantly increased modulated light output power of the AXEL.