Study On InGaAs/GaAs Strained Quantum Well Lasers

Long-wavelength materials which can be grown on GaAs substrate have been attracting much interest from the viewpoint of application to telecommunication. Owing to the critical thickness constraints it has been difficult to achieve emission beyond 1.1 μ mwith InGaAs.The detailed study on InGaAs/GaAs highly strained quantum well laser structures are carried out in this paper. Basing on typical strained quantum well laser structure,we studied on highly strained quantum well laser structure, we experimentally determined the critical layer thickness for highly strain 1.2 μ m InGaAs/GaAs quantum wells of good crystal quality.The critical layer thickness is 8.5nm.It exceeds the value predicted by Matthews and Blakeslee.We demonstrate a highly strain 1.2 μ m InGaAs/GaAs quantum well laser by changing the growth condition such as decreasing the growth temperature,increasing the growth rate and increasing the V/III ratio.The lasing wavelengths for 680- μ m-long cavities are 1.192 μ m and 1.201 μ m for 1400- μ m-long cavities.The threshold density achieved was 275 A/cm~2 at a cavity length of 680 μ m,the internal efficiency and internal loss are 91%and 6.5cm~-1 respectively.This paper describes a new type jig which is used for facet coating of semiconductor laser.The experiment turns out that the new type jig can overcome obviously many defects of traditional technology and improve the characteristic of laser.