Wavelength-independent output power from an injection-tunable DBR laser

Injection-tunable three-section distributed Bragg reflector lasers emitting near 1.55 μm have been fabricated employing bulk 1.48-μm-bandgap InGaAsP in the tuning layer of the phase and Bragg sections. The gain in this material compensates for the increased absorption loss during tuning, which results in a nearly wavelength-independent optical output power. The maximum obtained output power is 28 mW ex facet, with a spectral linewidth around 5 MHz.