HIGHLY RELIABLE AND STABLE-LATERAL-MODE OPERATION OF HIGH-POWER 0.98-MU-M INGAAS-INGAASP LASERS WITH AN EXPONENTIAL-SHAPED FLARED STRIPE

A 0.98-mu m InGaAs-InGaAsP-GaAs strained quantum-well (QW) laser with an exponential-shaped flared stripe is proposed for high-power, highly reliable operation. The stripe width is wider at the front facet to r educe the optical density by widening the spot size. The stripe width is narrower at the rear facet for stable lateral-mode operation. The s tripe width in the transient region is varied exponentially along the cavity for smooth mode transformation. We showed that this structure e xpands the spot size effectively without any deterioration in stable l ateral-mode operation. The kink-ocurrence output power is determined o nly by the stripe width at the rear facet, and the spot size at the fr ont facet is a function only of the stripe width at the front facet. T he maximum output power is 40-60% higher than that of ordinary straigh t-stripe lasers for the same kink-occurrence output power. Testing at 150 mW showed stable operation with an estimated lifetime of more than 200 000 h at 25 degrees C.