Research On Tunable Semiconductor Laser For Next-Generation Ethernet

Ethernet has become a widely spread networking technology because of its advantages of low-cost, high-reliability, ease of installation and maintenance. With the demand for greater bandwidth of data transmission and access network, Ethernet technology has gradually gone through stages of standard Ethernet, Fast Ethernet, Gigabit Ethernet, etc. The use of Ethernet in telecommunication and data center area is driving the fast commercialization of 40 Gb/s and 100 Gb/s Ethernet. However, currently available optical transmitters for next-generation Ethernet are mostly based on DFB lasers. The widely use of them is restricted by their complicated fabri-cation process and high cost. V-coupled cavity tunable semiconductor laser can not only solve this problem, but also meet the need of dynamic networking in the future. Thus, this thesis is mainly devoted to the study of V-coupled cavity tunable laser for next-generation Ethernet.Firstly, the basic structure and principle of V-coupled cavity laser were introduced. This structure was put into use in the design of 1310 nm band tunable laser. AlGaInAs material was used in the multiple quantum wells (MQWs) structure to promote the temperature stability of the laser. And wafer layer structure and waveguide structure were redesigned based on it. The parameters of resonant cavities were optimized to have large wavelength tuning range as well as good side mode suppression ratio (SMSR). In the design of half-wave coupler, two extension regions were added to reduce its excess loss.Then, according to the design, we fabricated the actual devices, analyzed the reasons of not-vertical waveguide sidewall and AlGalnAs MQWs lateral etching phenomenon. The fabri-cation processes were improved and 1310 nm band V-coupled cavity tunable laser with excellent performance was fabricated. The laser realized 22 x 100 GHz wavelength switching with more than 30 dB SMSR through single electrode thermal tuning.Finally, V-coupled cavity tunable laser that meets 100GBASE-LR4 specification was desi-gned. And time-domain travelling-wave model was applied to simulate its static and dynamic characteristics. By using the current injection tuning mode, introducing a passive waveguide as tuning region, optimizing the electrode structure, shortening the resonant cavities'lengths and reducing the length difference between two cavities, the V-coupled cavity tunable laser achieved 21 x 200 GHz wavelength switching in a single FSR as well as good performance in 25 Gb/s directly intensity modulation, which could meet the need of next-generation Ethernet.