Single-mode 200mW 660nm to 690nm red laser diode for sensing and medical application

Laser light sources have being used in sensing and medical applications, and it is required for higher power, high efficiency, good beam quality and high reliability. We demonstrated single-mode CW 200mW red laser diodes with wavelength of 660nm, 675nm, and 690nm. These were fabricated from AlGaInP-based material with narrow stripe. These showed good temperature characteristics that the highest power reached 250mW upto 70°C and 200mW at 90°C for 660nm laser, exceeded 250mW upto 90°C for 675nm and 690nm lasers. Each characteristic temperature T0 was 112K, 169K, and 201K, respectively. The wall plug efficiency exceeded 32% at 25°C. The far field pattern showed Gaussian-like single transverse mode. Stable operation at high temperature was demonstrated in 1,500hours at 60°C, CW 200mW for 660nm laser and in 1,000hours at 100°C, CW 200mW for 675nm and 690nm lasers. CW 200mW operation is the world’s first in single-mode 660nm to 690nm laser diodes to the best of our knowledge. In the case of AlGaInPbased material, although longer wavelength is concerned degrading crystal quality in the active layer due to increasing lattice mismatch, no degradation observed the characteristics and the reliability. These red laser diodes will contribute to progress for sensing and medical applications.