Temperature Dependent Behavior of the Optical Gain and Electroabsorption Modulation Properties of an InAs/GaAs Quantum Dot Epistructure

Abstract

In this work, the feasibility of a monolithically integrated laser and electroabsorption modulator based on the same active quantum dot epistructure is studied. The net modal gain and the absorption in the modulator were measured using the segmented contact method from 25 °C to 125 °C. The maximum of the net modal gain active region of the laser decreases from 10 cm-1 at 25°C to 3.9 cm-1 at 125 °C. The non-optimized maximum extinction ratio of the modulator, 4.1 dBmm-1 , is almost constant until 25 °C. The wavelength at which the net modal gain and the change in absorption are maximum, shift with temperature by 0.04 eV.

QCSE and Carrier Blocking in P-modulation Doped InAs/InGaAs Quantum Dots

“…The segmented contact method was utilized to measure the QCSE in the QD active regions [6]. The active regions used are similar to those we have already measured in [5]. The only difference in the current stack is that the doped stack has a doping concentration in the QD active region of 10 holes per dot.…”

“…Given the different nature of the states present in QDs, it is expected that modulation doping may lead to even further enhancements to electro-absorption modulator (EAM) performance [1]. QDs also offer the promising prospect of greater temperature tolerance [5], and so here we present a comparison of two identical QD active region stacks, except where p-modulation doping is present in one. We measure the QCSE in both stacks with temperature to determine their potential performance as EAMs, and we show that the inclusion of the p-modulation doping in the stack offers up to 3x larger figure of merit (FoM).…”

Modelling the effects of p-modulation doping in InAs/InGaAs quantum dot devices

“…Extinction ratios (ERs) of 10 dB for a voltage swing between 0 and 10 V were measured by (Ngo et al 2009), with ER and IL of 13 dB and 14.8 dB subsequently measured (Ngo et al 2010) for 10-layer structures. Finally (Le Boulbar et al 2019) characterised a near constant ER of 4.1dBmm −1 between 25 °C and 125 °C, suggesting temperature insensitivity across a wide range. To our best knowledge, only (Mahoney et al 2021) has directly compared measurements of the QCSE in p-doped structures.…”

Measurement of the quantum-confined Stark effect in $InAs/In(Ga)As$ quantum dots with p-doped quantum dot barriers

“…𝑄𝐷 devices have this advantage over competing technologies, particularly quantum wells (𝑄𝑊 𝑠). Furthermore, 𝑄𝐷 lasers offer the prospect of greater temperature tolerance [3], which is fundamentally due to the large energy spacing of conduction states found within the dots. The larger energy spacing prevents any carriers from getting thermally excited to higher states [4] and reduces wavelength drift in the laser.…”