Performance of 1.3 μm ridge waveguide distributed feedback lasers fabricated by one-step metalorganic chemical vapour deposition

Ridge waveguide distributed feedback (DFB) lasers emitting at 1.3 μm wavelength have been fabricated by one-step metal-organic chemical deposition over a first order grating in an InP substrate. Threshold currents as low as 13-18 mA were obtained for devices with as-cleaved facets and 15-20 mA for devices with one AR-coated facet. A slope efficiency as high as 0.32 mW/mA, single mode performance up to 20 mW, and a side mode suppression ratio of 45 dB have been achieved. For lasers with a coupling×length product, κL, of 2.5-3.5 and the single longitudinal-mode detuned 10-20 nm to the shorter wavelength side of the material gain peak, a high resonance frequency and a small wavelength chirp have been observed. Small signal frequency responses were measured with a -3 dB bandwidth of 11 GHz at 12 mW output power. The devices showed good open eye patterns under direct modulation up to 10 Gbit/s