Optimization of n-DBR in high power vertical-cavity surface-emitting laser under a short pulsed operation

The dependent of threshold current, output power and wall-plug efficiency on the reflectivity of n-distributed Bragg reflector (DBR) is simulated theoretically. The vertical-cavity surface-emitting laser (VCSEL) single device and arrays are fabricated and tested using waveform analysis method. The pulse width and repetition rate are 60 ns and 100 Hz, respectively. The peak output power of single device with an aperture of 500 μm is up to 102 W, corresponding to a power density of 52 kW/cm ², when the injection current is 110 A. The peak powers of 4×4 and 5×5 arrays are 98 W and 103 W at 100 A. The output power and the spectra of single device are compared at different injection currents under continuous wave (CW), quasi-CW (QCW), and pulsed operation, respectively. It is also concluded that the red shift rate of lasing wavelength is 0.92 nm/A and 0.3 nm/A, the temperature rise is 85°C and 180°C under CW and QCW operation, respectively. While it is only 0.0167 nm/A under pulsed operation, the corresponding temperature rise at 6 A is 1.5°C, which is far less than that under the other two conditions. That is why the peak power is so high under pulsed operation.