High temperature continuous-wave operation of 1.3- and 1.55-μm VCSELs with InP/air-gap DBRs

We demonstrate novel electrically pumped 1.3- and 1.55-μm vertical cavity surface emitting lasers (VCSELs) with two InP/air-gap distributed Bragg reflectors (DBRs). The active regions comprise conventional InGaAsP multiple quantum wells. A tunnel junction is placed between the active region and the top DBR to convert electrons into holes, thus minimizing the use of p-type material in the structure to reduce the free-carrier loss and achieve current confinement. The whole structure was grown in a single growth run by low-pressure metal-organic chemical vapor deposition (MOCVD). For both 1.3and 1.55-μm emission wavelengths, air-gap DBR VCSELs exhibit room-temperature continuous wavelength (CW) threshold current density as low as 1.1 kA/cm
²
, differential quantum efficiency greater than 30%, and CW operation up to 85°C. The single-mode output power was 1.6 mW from a 1.3 μm VCSEL with a 6.3-μm aperture and 1.1 mW from a 1.55 μm VCSEL with a 5.7-μm aperture under room temperature CW operation.