Gain spectra of 1.3μm GaInNAs laser diodes

Abstract

We present an experimental investigation of the optical gain properties of 1.3μm GaInNAs double quantum well ridge waveguide laser diodes. High-resolution gain spectra versus injection current and temperature were obtained by measuring the modulation depth introduced into the spontaneous emission spectrum by the Fabry-Pérot resonances. As the injection current increases, the modal gain spectral peak experiences a small blueshift over the photon energy, and the magnitude increases asymptotically, saturating at the lasing threshold level of 24.4cm−1. The peak of the modal gain spectra exhibits a redshift with an average rate of 0.58nm∕°C as the temperature increases from 30to50°C. For wavelengths corresponding to photon energy below the band gap, the modal gain spectra converge to the internal loss of 7cm−1. The full width at half maximum of the gain spectrum is 41.1meV at 30°C, 40mA and increases with injection current at a rate of 0.42meV∕mA. The high optical gain and low internal loss indicate that GaInNAs is a promising active material for long wavelength laser diodes.