Abstract

Laser diodes with wavelengths of 1.5 μm are important in high speed and long distance optical fiber communication systems because of their low transmission loss in silica fiber and their applicability to erbium-doped fiber amplifiers. To improve the laser diode’s performance, namely, to decrease the threshold current and increase optical output power, the graded-index separate-confinement-heterostructure multiple InGaAs/InGaAsP quantum well (GRIN-SCH-MQW) laser structure with strained-quantum wells has been studied.^1,2 It is noted that GRIN-SCH-MQW structure can enhance carrier collection and optical confinement in the laser diode, thus the optical output power can be increased. A strained layer in a quantum well can reduce the in-plane hole effective mass so that the laser threshold current, Auger recombination, and intervalence band absorption will be reduced. However, for a given lasing wavelength, the thickness of a strained-InGaAs well is far narrower than the unstrained-InGaAs one, which decreases the confinement factor and also is difficult to grow with well-controlled thickness.

© 1993 Optical Society of America