Simulation of the Optimized Structure of a Laterally Coupled Distributed Feedback (LC-DFB) Semiconductor Laser Above Threshold

M Seifouri,A Faraji

doi:10.48084/etasr.376

Abstract

In this paper, the laterally coupled distributed feedback semiconductor laser is studied. In the simulations performed, variations of structural parameters such as the grating amplitude a, the ridge width W, the thickness of the active region d, and other structural properties are considered. It is concluded that for certain values of structural parameters, the laser maintains the highest output power, the lowest distortion Bragg frequency δL and the smallest changes in the wavelength λ. Above threshold, output power more than 40mW and SMSR values greater than 50 dB were achieved.

Highlights

The semiconductor DFB lasers, due to their low threshold current, narrow line width and single mode capability, are considered as the optical source in communications systems [1]
Conventional DFB lasers with coupling refractive index with end facets coated with anti reflection (AR), are not singlemoded and have two symmetrical modes relative to Bragg mode that appear simultaneously in the laser output
This article reports on the stability of LC-DFB lasers against Spatial Hole Burning (SHB), maximum output power and Side Mode Suppression Ratio (SMSR) values above threshold conditions

Summary

INTRODUCTION

The semiconductor DFB lasers, due to their low threshold current, narrow line width and single mode capability, are considered as the optical source in communications systems [1]. One way for having a single mode in AR DFB laser is by employing an equivalent phase shift at the center of the grating structure. These lasers are named QWS–DFB and have high efficiency but are sensitive to the reflection at the facets. LCDFB lasers use a lithographic fabrication step to define the distributed feedback grating, avoiding subsequent regrowth. This makes this type of lasers easier to fabricate and less expensive [2,3,4,5,6,7].

THEORETICAL AND PHYSICAL MODEL

RESULTS AND DISCUSSIONS

CONCLUSION