1.3 μm InGaAlAs/InP DFB Laser Integrated With SSC Having Reverse Mesa Ridge Waveguide

We report the fabrication of a
$1.3~\mu \text{m}$
InGaAlAs/InP multi-quantum well (MQW) distributed feedback (DFB) laser integrated with a laterally tapered spot size converter (SSC) having a reverse mesa ridge waveguide. Because the top waveguide width of the reverse mesa waveguide is notably larger than the bottom width, a narrow SSC tip width, which is key for high quality SSC, can be fabricated by using conventional photolithography easily, helping to lower the device cost. At 25 °C, the emission wavelength is around 1314 nm and side mode suppression ratio larger than 45 dB can be obtained when the current is larger than 100 mA. The lateral and vertical divergence angles measured from the SSC facet of the laser are 11.8 and 13.2, respectively, which helps to ease the outcoupling of the light power.