Anomalous wavelength changes of 980-nm pump laser diodes with antireflection coatings

We have observed abrupt wavelength jumps form 980-nm pump laser diodes with an antireflection (AR) coating when the injection currents were changed. The width of the anomalous jumps becomes wider as the cavity length is shortened. It was clarified from theoretical calculations that the phenomenon is caused by narrow mirror loss distributions. It was also confirmed that wide AR coatings or a long cavity can avoid these abrupt wavelength jumps.