Gain-coupled distributed feedback lasers in the blue-green spectral range by focused ion beam implantation

Abstract

We have observed gain-coupled distributed feedback (DFB) laser emission from CdZnSe(Zn,Mg)(S,Se) structures at room temperature. First order DFB gratings with periods in the 90 nm range were defined by maskless Ga+-implantation using a focused ion beam technique. For optical pumping a lasing threshold of about 100 kW/cm2 was found. The DFB emission is characterized by single mode emission and a temperature dependence of ΔEΔT = −0.11 meV/K, reduced by a factor of four compared to the spontaneous emission. From the Bragg condition a wavelength dispersion of the effective refractive index of ΔneffΔλ = −0.23 × 10−2nm−1 and a temperature variation of the refractive index of ΔneffΔT = 1.7 × 10−4K−1 can be deduced.