Carrier Dynamics of Broadband Semiconductor Lasers
Date Issued
2007
Date
2007
Author(s)
Su, Yi-Shin
DOI
zh-TW
Abstract
In this dissertation, we further study the behaviors of quantum dot lasers. The topics include two types of anti-competition behaviors and the stability of quantum dot external cavity lasers.
In the first type anti-competition behavior, the laser corresponding to the excited-state emission wavelength assists the laser corresponding to the ground-state emission wavelength to gain more carriers. In our experiment, the excited-state laser emission is at 1170 nm. The ground-state laser emission is between 1240 nm to 1265 nm. This anti-competition behavior is most obvious when the ground-state laser emission is between 1245 nm to 1250 nm or is at 1260 nm.
In the experimental setup for the second type anti-competition behavior, the laser diode can oscillate by it self at 1250 nm. The second type anti-competition behavior occurs when the external cavity induces another laser oscillation at the ground-state wavelength. The emission of the excited-states at 1170 nm wavelength increases by more than 10dB. This effect is most obvious when the wavelength of the laser induced by the external cavity differs from 1250 nm by 15 nm.
The second topic in this dissertation is the stability of the quantum dot external cavity laser. The current range in which the quantum dot external cavity laser can operate stably is smaller than that of the quantum well external cavity laser. The experiment indicates that the quantum dot external cavity laser tends to be more unstable when the cavity length increases, and when the feedback efficiency decreases. The unstable behavior is theoretically confirmed to be relating to the characteristics of the quantum dot materials. The first is the finite carrier transition time between the ground state and the excited state inside a quantum dot. The second is the shift of the Fabry-Perot mode wavelength versus the excited-state carrier population.
Subjects
半導體雷射
量子點
光放大器
semiconductor laser
quantum dot
optical amplifier
Type
thesis