【摘要】 对不同阱宽的梯度折射率分别限制单量子阱激光器进行了TE、TM模的光增益谱测量对于阱宽大于120A的激光器,发射光谱和光增益谱都出现双峰,分别是由n=1和n=2的子带跃迁所造成,激光振荡出现在n=2的子带跃迁。随着阱宽减小,n=1子带跃迁的饱和增益增加,使激光振荡能在n=1子带发生,而n=2子带的受激就需要比原来更大的注入才有可能。材料增益随阱宽减小呈超线性地增加,从而降低了n=1子带受激的最小腔长。因此,用较窄的量子阱(≤100A),高的端面反射率和尽可能短的腔长,就能得到很低的阈电流。TE和TM模增益谱的不同,使激光器在一定阱宽和腔损耗下具有不同的TE和TM激射波长。更多还原

【Abstract】 TE and TM polarized optical modal gains of graded-index separate-confinement singlequantum well lasers are measured in detail on the samples with different well widths. Forthe lasers with well width L_s>120A, the emission and gain spectra exhibit double peaks causedby n=1 and 2 subband transitions, respectively, lase oscillation takes place by n=2 subbandtransition. Reducing the well width, the saturation gain of the n=1 subband transition increases,laser oscillation will take place by n=1 subband transition, while the threshold currentdensity for n=2 subband lasing will increase. The superlinear increase of the material gainwith the decrease of the well width reduces the minimum cavity length for n=1 subband lasing.For the narrow well of L_z≤100A, the higher mirror reflectivity and shorter cavity lengthwill result in lower threshold current density. The lasers with the well width and cavity lossin a certain range oscillate at different TE and TM wavelength because of the difference betweentheir gain spectra.更多还原