Fabrication and characteristics of 40 Gb/s traveling-wave electroabsorption modulator-integrated DFB laser modules

We developed 40 Gb/s traveling wave electroabsorption modulator-integrated DFB laser (TW-EML) modules using several advanced technologies. This 40 Gb/s EML device adopted traveling wave electrode structures and showed the result that the measured 3 dB bandwidth of the electrical-to-optical (E/O) response reached about 45 GHz and the return loss (S₁₁) was kept below -10 dB up to 50 GHz. For the module designs of this device, electrical and optical factors were mainly considered. The measured S₁₁ of the fabricated 40 Gb/s TW-EML module was maintained below -10 dB up to about 30 GHz and the 3 dB bandwidth of the E/O response reached over 35 GHz. We also developed two types of CPW for the application of the driver amplifier integrated 40 Gb/s TW-EML module, which is a system-on-package (SoP) composed of a EML device and a driver amplifier device in a module. The measured S₁₁ of the two-step-bended CPW was kept below -10 dB up to 35 GHz and the measured S₁₁ of the parallel type coplanar waveguide (CPW) was kept below -10 dB up to 39 GHz