Emitting far field pattern study of long wavelength grating coupling surface emitting lasers

We demonstrate a very low threshold 1.55 /spl mu/m grating coupled surface emitting laser (GCSEL) with a CW room temperature threshold of only 6 mA. The laser structure is a multi-quantum well distributed-feedback (DFB) laser with a second order grating buried under the gain medium. The laser is fabricated by following the capped-mesa buried heterostructure (CMBH) process with a stripe width of around 0.9 to 1.2 /spl mu/m wide. We have measured the FWHM of the far field intensity profile of the laser.