TM/TE polarization tuning and switching in tensile strained p-AlGaAs/GaAsP/n-AlGaAs heterostructures by uniaxial compression

Abstract

Numerical calculations and experimental results show that, for the broad range of tensile strained p-Al x Ga 1−x As/GaAs 1−y P y /n-Al x Ga 1−x As heterostructures widely used in commercial laser diodes emitting at 766-808 nm, polarization of emitted light may be extremely sensitive to external uniaxial stress due to the change of wave functions symmetry and possible optical transitions in the quantum well levels system. In some heterostructures with quantum well width of 10 nm and phosphorus content below 0.08, TM/TE polarization mode relation showcases a several times decrease and even dominant polarization mode switching under moderate compression of about 5-6 kbar in [100] and [110] directions.

Temperature and deformation dependence of p-AlxGa1−xAs/GaAs1−yPy/n-AlxGa1−xAs laser diode wavelength and polarization

“…The calculations are performed under compression up to 10 kbar along the main in-plane [ [6], this effect may be specially increased in p-Al x Ga 1-x As/GaAs 1-y P y /n-Al x Ga 1-x As structures by the proper choice of quantum well thickness and composition. In this aspect, some devices for effective TM and TE polarization modes tuning and switching under uniaxial stress based on p-Al x Ga 1-x As/GaAs 1-y P y /n-Al x Ga 1-x As laser diode structures are possible.…”

“…[5,6] [8] was self-consistently solved together with Poisson's equation for the electrostatic potential using the finite-difference k⋅p method. Numerical calculations were fulfilled in the framework of the program "Heterostructure Design Studio 2.1" in the vicinity of the zone centre at the Γ point.…”

“…In our recent papers [5,6] systematic experimental study and numerical calculations of external uniaxial compression P influence on the energy spectrum, wave functions, and the optical gain g TE , g TM of TE and TM polarization modes in p-Al x Ga 1-x As/GaAs 1-y P y /n-Al x Ga 1-x As laser diode structures of different quantum well (QW) thickness and composition were performed for temperature T = 77 K and P ║ [110] direction. According to the experimental study [6], under [110] uniaxial compression (P ≈ 5 kbar) the electroluminescence spectrum in p-Al x Ga 1-x As/GaAs 0.84 P 0.16 /n-Al x Ga 1-x As laser diodes demonstrates a blue shift up to 25 meV, while the intensity of light in the plane normal to the heterostructure reveals not only the strong increase under compression in [110] direction, but also evident decrease of relative TM/TE intensity ratio.…”

“…According to the experimental study [6], under [110] uniaxial compression (P ≈ 5 kbar) the electroluminescence spectrum in p-Al x Ga 1-x As/GaAs 0.84 P 0.16 /n-Al x Ga 1-x As laser diodes demonstrates a blue shift up to 25 meV, while the intensity of light in the plane normal to the heterostructure reveals not only the strong increase under compression in [110] direction, but also evident decrease of relative TM/TE intensity ratio. Very good agreement between numerical calculations and experimental results for the structure with GaAs 0.84 P 0.16 quantum well of 14 nm width under uniaxial compression along [110] direction makes the results of numerical calculations for p-Al x Ga 1-x As/GaAs 1-y P y /n-Al x Ga 1-x As laser diode structures, performed with other QW compositions, thickness, and other directions of applied stress, quite reliable.…”

Методы переключения поляризации излучения в GaAs лазерных диодах

“…Стандартные" методы создания поляризации, основанные на преобразовании света с помощью электрооптических кристаллов, уже не удовлетворяют требованиям компактности и интегрируемости в оптоэлектронную схему. Одним из новых принципов управления поляризационными свойствами излучения является использование анизотропии преломления оптического кристалла за счет приложения внешнего воздействия [4,5]. Приложение внешнего воздействия (механическое сжатие) позволяет понизить степень симметрии лазерного кристалла, благодаря чему в кристаллах кубической сингонии (в том числе A 3 B 5 ) становится возможным существование двух взаимно перпендикулярных направлений поляризации (явление двулучепреломления).…”