Theoretical analysis of tuning properties for a phase-tunable DFB laser

The device consists of a conventional or a lambda /4-shifted DFB (distributed-feedback) laser monolithically integrated with an external waveguide section with separate electrodes for phase control. Tuning curves are presented for threshold current, frequency, linewidth, and output power. The analysis demonstrates a generally higher side mode suppression and larger frequency tuning range but also a larger linewidth for the lambda /4-shifted device compared to the device with a conventional DFB section.>