Surface-emitting GaInAsP/InP injection laser with short cavity length

We have succeeded in making a surface-emitting GaInAsP/InP injection laser with short cavity length (≅ 10 μm) which operates at 1.22 μm of wavelength with threshold current of 160 mA (33 kA/cm2) at 77 K. No side-emitting mode was observed as a result of preparing long absorbing regions and a small dot electrode (25 μm φ). One of the longitudinal modes, with a spacing of 170 Å, dominated above threshold and the far-field radiation angle was sharp (2Δθ = 10°).