Continuous-wave operation of 1.5μm InGaAs∕InGaAsP∕InP quantum dot lasers at room temperature

Abstract

Continuous-wave operation at room temperature from InGaAs∕InGaAsP∕InP quantum dot (QD) laser diodes (LD) has been achieved. A ridge waveguide QD LD with 7 QD-stacks in the active region lases at 1.503μm at 20°C and that with 5 QD-stacks lases at 1.445μm at room temperature. The shift in lasing wavelength is believed to be due to the difference in the quantized energy states involved in producing gain for lasing. With smaller number of QD stacks and shorter cavity length, the lasing wavelength shifts to shorter wavelength indicating that more of higher excited states are involved in producing gain. By increasing the number of QD stacks to 15, lasing at 1.56μm has been achieved under pulsed mode.

One-dimensional aligned InAs/InP quantum dots chain growth by metalorganic vapor phase epitaxy for 1.55μm application

“…In previous reports of the position controlled InAs QDs growth by various methods in different substrates, single dot or single line of dots was grown in the window area if the spacing is smaller than 100 nm while many dots were randomly distributed for the case of a larger window area [9,11,15]. The dot is not in a pyramid shape but elongated or coalesced along the grating direction of [1][2][3][4][5][6][7][8][9][10], as typical observed in InAs grown on InP [16,17]. The lateral size in the [1 1 0] direction is in the range of 30-40 nm.…”

“…Low threshold current density InGaAs/GaAs QD semiconductor lasers operating at room temperature have been achieved [1][2][3]. More recently, QDs emission around 1.55 mm for long haul optical communication wavelength have been demonstrated in InAs/InP QD systems using metalorganic vapor phase epitaxy (MOVPE) [4][5][6][7]. One drawback of self-assembly method is the random distribution of the QDs on a flat substrate.…”

Self-assembled InAs/InP quantum dots and quantum dashes: Material structures and devices

“…A small LEF of ~1.4-1.6 above threshold and < 1 below threshold, was measured recently by Jiao et al [125] which is half the value reported by Lelarge et al (~2.2 below threshold) [121], and the Qdots exhibited better uniformity with PL linewidth 63 meV at room temperature. Laser devices at low temperature [56] and room temperature [55,126] lasing from InGaAs Qdots on InGaAsP/(100)-InP were also reported with high Qdot density reaching value 1.1×10 11 cm -2 and with notable performances. Qdot lasers based on InAs/InGaAsP DoWELL [74] and InAs/InAs dot-on-well [127] active region design were also demonstrated after observation of their superior quality at material level which has been discussed in section 2.2.1.…”

Stacking, polarization control, and lasing of wavelength tunable (1.55μm region) InAs/InGaAsP/InP (100) quantum dots

“…The maximum achievable QD ground-state modal gain is estimated to be 14.7 cm À1 from the 1-mm long device which is the shortest one lasing on the ground-state transition. These values are among the best achieved [9][10][11], indicating the excellent quality and performance of our QDs. …”