1.3[m]m single-mode extended cavity GalnNAs/GaAs lasers produced using a sputtered SiO₂ quantum well intermixing technique
The research presented in this thesis describes the realisation of single-mode extended cavity GaInNAs/GaAs lasers. The GaInNAs/GaAs material system has gained much attention recently, and has been cited as a possible replacement to the InGaAsP/InP material system due to its greater high temperature performance, which can lead to improved device efficiency and higher output power. Incorporating an extended cavity to an active laser device using selective area quantum well intermixing (QWI) can be extremely advantageous, since mirror degradation and modal instabilities at high output powers can be suppressed. Characterisation of the GaInNAs/GaAs material used in this project was performed by fabricating oxide stripe lasers. Analysis of the lasers yielded a value of 720A/cm2 for the threshold current density of a device with an infinitely long cavity. Values for internal efficiency and loss were also calculated to be 62.5% and 18cm-1 respectively. Although the value for Jth= 720A/cm2 is almost twice the value for Jth8 of similar GaInNAs material reported by the same growers, it would prove sufficient in demonstrating the concept of the project. The successful demonstration of QWI on GaInNAs/GaAs material was achieved using the sputtered SiO2 intermixing technique. A differential wavelength shift of 40nm was achieved, which would prove sufficient for monolithically integrating extended cavities with GaInNAs laser devices.