High-performance directly modulated 1.3-mu m undoped InAs-InGaAs quantum-dot lasers

In this letter, we report on experimental results of directly modulated single-transverse mode 1.3-mu m InAs-InGaAs quantum-dot (QD) lasers in a wide temperature range. A 3.125-Gb/s data modulation over temperature with an extinction ratio up to 10 dB is reported. Moreover, 10-Gb/s eye patterns at 15 degrees C and 50 degrees C and 5-Gb/s modulation in the whole explored temperature range (15 degrees C-85 degrees C) are demonstrated. These results were obtained by exploiting heterostructures containing six layers of high modal gain InAs QDs grown without incorporation of p-doping in the active region or tunnelling injection structure implementation. QD lasers exhibited a saturation modal gain as high as 36.3 cm(-1), ground state lasing from short cavities down to 400-mu m length and a characteristic temperature of about 110 K in a large temperature range between 15 degrees C and 85 degrees C.