Design and Simulation of a Novel Three-Section Widely-Tunable Slotted Fabry-Pérot Laser

Wavelength tunable laser diodes especially widely-tunable lasers are generally regarded as key components for future optical telecommunication systems. The advantages of monolithic tunable lasers compared to a series of single-frequency distributed feedback lasers (DFBs) are well known as both low-cost and high-performance. However, these lasers require both high resolution processing and complex re-growth steps to manufacture. On the other hand, tunable lasers can be realized by distributing reflective defects (so-called slots) into conventional Fabry-Perot (FP) laser cavities. By carefully optimizing the slot positions and slot number, single mode laser lasing with a side mode suppression ratio (SMSR) of more than 40 dB has been achieved. This paper presents the design of a novel widely-tunable laser with channel spacing of 400 GHz based on slotted FP structures. This novel device structure is re-growth free, and thereby can be easily and cheaply fabricated and integrated compared with other traditional tunable devices. A simplified numerical model to analyze the tuning characteristics of the designed structure is also presented. In this model it is assumed that each section has a uniform carrier density and material gain. Numerical results show that the overall discrete tuning range over 30 nm can been achieved by employing the Vernier effect tuning. Within this tuning range, ten supermodes with SMSR more than 35dB are obtained. A more complicated and much slower model with the stimulated emission included in the mirror sections show similar simulation results.