Single transverse mode condition of surface‐emitting injection lasers

The surface‐emitting laser can be fabricated monolithically via planar technology and mass‐produced for applications to laser discs and optical IC's for optical communication. However, the transverse mode control in the surface‐emitting laser, which is important to laser oscillation, has not been well studied. This paper discusses the transverse mode control for the surfaceemitting laser and clarifies the shape of the single transverse mode in the structure. As a result of the calculation for a laser wavelength of 1.3 μm, if the composition of the waveguide core (the carrier‐confining layer) is λ = 0.93 μm in a structure where a waveguide is built in the cavity, the waveguide radius must be less than 2 μm. For a structure where only the active layer is embedded, the radius of the reflector must be 3 to 4 μm or the radius of the active region must be 5 to 7 μm when the reflector radius is 10 μm. Therefore, even in the surface‐emitting laser, the transverse mode control can be achieved relatively easily.