Research On Electroabsorption Modulated Lasers

With the landing of 5G mobile networks,the establishment of a large number of enterprise data centers,and the promotion of cloud computing,data traffic continues to increase every year,and at the same time there are higher requirements for data transmission rates and bit error rates.Electroabsorption modulated laser(EML)is an important light source for short-and medium-distance communication.By integrating external modulators,higher transmission rates and transmission distances can be obtained.This thesis takes EML for short-and medium-distance communication as the research object,and the main research contents are as follows:(1)Simulated a two-section DFB laser based on the time-domain traveling wave method,studied the influence of the length of the active area and the reflection area,the position of the phase shift and other structural parameters on the laser output power,side mode suppression ratio,carrier distribution in the cavity.The process development and fabrication of the laser have been completed,and a distributed feedback(DFB)laser for integration has been demonstrated with a side-mode suppression ratio of 55 d B.(2)The electrical model of the electro-absorption modulator has been established.The quantum well and device structure of the electro-absorption modulator are designed.Used HFSS simulation software to establish the model for a high-speed carrier,and analyzed the cause of electrical resonance from theory,and optimized the electrode distribution and through-hole design.The heat sink can keep the signal reflection below-18 d B in the range of 0-40 GHz.The fabrication of the electro-absorption modulator was completed,and the static performance was tested.The static extinction ratio reached 20 d B.It was welded to the carrier for small-signal modulation test,and a 26.5 GHz modulation bandwidth was obtained.(3)Designed an EML based on the identical quantum well structure,established a model to analyze the effect of end-facet reflection on the small signal modulation performance.Completed the device fabrication and characterization.The SMSR of the laser reaches 50 d B,the static absorption can reach 28 d B,and the absorption slope is up to 12 d B/V.It has realized a small signal modulation bandwidth of 2 GHz.The reasons for the limitation of bandwidth are analyzed.(4)Explored the coupler structure of the EML for three different integration schemes,established the simulation model through Rsoft simulation software,analyzed the energy coupling process in the simulation,optimized the structural parameters,and obtained high coupling efficiency and large fabrication tolerance.