Low Threshold $1.55\ \mu\mathrm{m}$-Band Quantum Dot Laser Diode with InP(311)B Substrate

We successfully improved characteristics of ridge structured QD-LD and demonstrated threshold current of 9.5 mA and corresponding threshold current density of 0.34 kA/cm
²
, whose value was the lowest class previously reported as
$1.55 \mu\mathrm{m}$
-band edge emitted type QD-LDs to the best of our knowledge.