Quantum Dot Rolled-up Microtube and Edge Emitting Lasers.

Quantum Dot Lasers;Electrical Engineering;Engineering;Electrical Engineering

Bhowmick, SishirPhillips, Jamie Dean ;

University of Michigan

关键词: Quantum Dot Lasers;    Electrical Engineering;    Engineering;    Electrical Engineering;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/102302/sishir_1.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Infrared lasers emitting at 1.3 and 1.55 µm are the workhorses for fiber optic communication. Commercial lasers used at these wavelengths are generally GaAs and InP based quantum well lasers which suffer from undesirable characteristics including higher threshold, limited small-signal modulation bandwidth and most notably poor temperature stability. Due to their unique optoelectronic properties, lasers incorporating quantum dots can have better temperature stability, chirp-free high speed operation, and higher modulation bandwidth compared with those incorporating equivalent quantum wells which make them a favorable candidate for practical applications.A novel InAs/GaAs quantum dot rolled-up microtube laser formed by an epitaxial strain-driven mechanism has been investigated. Simplified analytical expressions have been derived for the scattering (radiation) loss at the microtube notches, the bending loss, and the substrate loss and their values have been calculated as a function of tube diameter. The threshold condition for a microtube laser has been derived from which it is found that the threshold excitation (power) is inversely proportional to the microtube diameter. A rolled-up microtube directional coupler made of twin tubes has demonstrated. The coupling characteristics have been measured in isopropyl alcohol as the surrounding media to demonstrate the potential of the device as a fluid sensor. A rolled-up microtube consisting of a microtube laser, a microtube detector and a waveguide connecting them has also been demonstrated. The rolled-up microtube detector exhibits a very low dark current and the responsivity of the phototransceiver circuit is 34 mA/W. The growth of self-organized InAs/In0.53Ga0.23Al0.24As/InP quantum dots has been investigated. Quantum dot lasers incorporating modulation p-doping of the active region and a tunnel injection structure operating at 1.56 µm have been demonstrated. The lasers are characterized by high temperature stability with characteristics temperature T0 = 227 Kand 100 K for the temperature range 5 C ≤ T ≤ 45 C and 45 C < T ≤ 75 C, respectively. The maximum measured -3 dB small-signal modulation bandwidth is 14.4 GHz. The lasers exhibit a very small chirp of 0.6 Å for a modulation frequency of 10 GHz and a near zero α-parameter at the peak of the laser emission.