Comparison of Fe- and p/n/p-Doped InP as a Current Blocking Layer for Monolithically Integrated InGaAsP/InP Laser Diodes with Passive Waveguides

We have fabricated InGaAsP/InP waveguide integrated laser diodes for the 1550 nm wavelength region. The passive waveguide was butt-coupled using the CH 4 /H 2 reactive ion etching and metal-organic chemical vapor deposition regrowth techniques. We compared the performances of waveguide integrated laser diodes with different current blocking layers, i.e., Fe-doped InP and p/n/p-doped InP layers. On the whole, Fe-doped InP was better than p/n/p-doped InP as a current blocking layer. In particular, the reverse leakage current through the butt-coupling region with Fe-InP current blocking layer was approximately 99.9 µA, while that with p/n/p-InP was 193.7 µA. We also discussed the leakage current characteristics of waveguide integrated laser diodes with analyses of I d V /d I vs I curves.