The TJS lasers which have the kink-free behavior and good proportionalities in the outputs between the front mirror and the rear mirror have been tested by cw aging. After 12,000-hour cw againg, a TJS laser has been found to still lase in a single longitudinal mode as well as in the fundamental transverse mode. The life of TJS lasers at 25 is estimated to be at least 80,000 hours on the basis that the laser is still alive after 3,000-hour aging at 60. By considering that the spatial homogeneity in the active region of the TJS laser is maintained for long time cw aging, the reason why the single mode behavior is kept even after the aging can be explained. Here, the spatial homogeneity in the active region of the TJS laser may be due to a small size of the region and to high hole concentration of the region.

Static characteristics of InGaAsP/InP double-hetero-structure laser diodes with stripe geometry have been examined. Relation between stripe width and "kink power", Pk, where a kink appears in the light output vs. current curve, is demonstrated experimentally. It is shown that a 7 µm-wide stripe laser diode exhibits the stable fundamental transverse mode oscillation as well as the single longitudinal mode oscillation. Growth rate of TM mode is found to be remarkably reduced after TE mode oscillates in the 7 µm-wide stripe mode stabilized laser. The dependence of threshold current, Ith, on the stripe width is examined experimentally and Ith is found to increase when the stripe width is decreased to less than about 10 µm. By taking mode loss into consideration, the increase in Ith with narrowing the stripe width is explained.