43 Gb/s 1.3 $\mu$ m DFB Laser for 40 km Transmission

We describe the performance of 1.3 $\mu$ m InGaAlAs ridge waveguide multiple quantum-well distributed feedback lasers. We obtained a 3 dB down bandwidth frequency of around 30 GHz by shortening the cavity length of the laser. We demonstrated experimentally that it is possible to obtain clear eye opening at a 43 Gb/s modulation speed after a 40 km single-mode fiber (SMF) transmission using a directly modulated laser. We fabricated a compact transistor outline (TO)-CAN module whose volume was about $1/19$ that of a conventional butterfly package. We successfully obtained clear eye opening for a 40 km SMF transmission at 43 Gb/s with the TO-CAN module.