Junction Temperature Measurement of InAs Quantum-Dot Laser Diodes by Utilizing Voltage-Temperature Method

Junction temperature of InAs quantum-dot laser diodes (LDs) is measured by utilizing a forward voltage- temperature method. Although the forward voltage decrease with junction temperature increment is low, the linear relation between forward voltage and temperature clearly occurs. It is found that SiN x is more useful than SiO 2 to keep junction temperature low. Injection current to shift the lasing wavelength from ground to excited state is increased over 200 mA by using SiN x instead of SiO 2 as the insulating layer. As a result, ground state optical power is doubled.