GaAs/AlGaAs surface emitting laser diode with vertical distributed feedback optical cavity and transverse junction buried heterostructure

A threshold current of 2 mA at room temperature CW operation is realized in a vertical distributed feedback surface emitting laser diode (VDFB-SELD) with transverse junction buried heterostructure (TJBH). In this TJBH structure, the vertical distributed feedback active region (AlGaAs/GaAs multilayer) is entirely surrounded by N- and P-type AlGaAs cladding layer for minority carrier confinement. The far field angle is 7 to 8 degrees. The beam shape is nearly circular. However, the lasing spectrum is broad ( 1.5 to 3 nm) compared with the conventional edge-emitting laser. Theoretical model of the VDFB-SELD-TJBH by using DFB theory and its computer simulation of the spectrum shows good agreement with the experimental measurements.