Direct amplitude modulation of the radiation emitted by (InGa)AsP/InP double-heterostructure lasers (λ = 1.3 μm) with separate confinement

A study was made of the dynamics of the emission of radiation from buried mesa-stripe injection lasers consisting of (InGa) AsP/InP double heterostructures with ultrathin (d_α = 12–25 nm) active layers and separate confinement (λ = 1.3 μm). Depending on the width W of the active strip, the threshold current varied within the range (0.5–3.0) X 10³ A/cm². The maximum cw output power reached 1.0 W (W = 100 μm). A considerable scatter of the parameters of the direct amplitude modulation (amplitude-frequency characteristics, transient characteristics, amplitude noise, nonlinear distortion) was observed. The most effective analog amplitude modulation at frequencies in excess of 1 GHz was achieved for lasers with a narrow active channel (W ≈ 4 μm) emitting one spatial mode. A study was made of the dependences of the relative intensity noise, and of nonlinear and intermodulation distortions on the pump current reaching the laser, and on the frequency and depth of modulation.