Tunable self-injection locked green laser diode

We report, to the best of our knowledge, the first employment of a self-injection locking scheme for the demonstration of a tunable InGaN/GaN semiconductor laser diode. We have achieved a 7.11 nm (521.10-528.21 nm) tunability in a green color with different injection currents and temperatures. The system exhibited mode spectral linewidth as narrow as ∼69 pm and a side mode suppression ratio as high as ∼28 dB, with a maximum optical power of ∼16.7 mW. In the entire tuning window, extending beyond 520 nm, a spectral linewidth of ≤ 100 pm, high power, and stable performance were consistently achieved, making this, to the best of our knowledge, the first-of-its-kind compact tunable laser system attractive for spectroscopy, imaging, sensing systems, and visible light communication.