Directly modulated semiconductor lasers (DMLs) are important components as sources for short distance communication. In this paper, we present 1.3μm directly modulated lasers with high modulation bandwidth based on high-order slotted surface gratings. Such lasers are regrowth free, thus have the advantages of low cost and high reliability compared to the typical distributed feedback Bragg (DFB) lasers with buried gratings. The two dimensional (2D) scattering matrix method (SMM) combined with the time-domain travelling-wave model (TDTW) is employed for the analysis of the designed laser. By optimization of the grating parameters and cavity length, the slope efficiency about 0.35mW/mA and 3-dB-down frequency bandwidth higher than 41GHz have been achieved for a 250μm long high-order slotted surface grating laser.
In this paper, a single facet slotted Fabry-Perot (FP) laser is demonstrated to provide tunable, single mode operation and
has been monolithically integrated into a photonic integrated circuit (PIC) with semiconductor optical amplifiers and a
multimode interference coupler. These lasers are designed by incorporating slots into the ridge of traditional FP cavity
lasers to achieve single mode output, integrability and tunability. With the feature size of the slots around 1μm, standard
photolithographic techniques can be used in the fabrication of the devices. This provides a time and cost advantage in
comparison to ebeam or holographic lithography as used for defining gratings in distributed feedback (DFB) or
distrusted Bragg reflector (DBR) lasers, which are typically used in PICs. The competitive integrable single mode laser
also enables the PIC to be fabricated using only one epitaxial growth and one etch process as is done with standard FP
lasers. This process simplicity can reduce the cost and increase the yield.