Study On Controllable Phase Shift Semiconductor Laser With Three Electric Electrodes Based On Reconstruction Equivalent Chirp Technique

With the continuous development of optical fiber communication network,the demand of transmission capacity and transmission speed increases rapidly.This makes the dense wavelength division multiplexing(DWDM)technology widely used in optical communication.When wavelength-fixed lasers are utilized in the DWDM systems,the cost,energy consumption,and volume of communication networks will increase dramatically.Therefore,wavelength tunable semiconductor lasers should be introduced to reduce these problems.Based on the reconstruction equivalent chirp(REC)technology,we fabricate a three-electrode semiconductor laser.Firstly,the classification and research status of tunable semiconductor lasers are introduced.Then the coupled mode theory and transfer matrix method are introduced.The numerical simulation of a three-electrode laser with an equivalent phase shift grating is carried out using the transfer matrix method.The results show that we can change the output wavelength by changing the injection current ratio of different electrodes and introducing controllable distributed phase shift into the laser.In this thesis,the wavelength tuning mechanism of the proposed laser structure is analyzed,and the phenomenon of mode stability transition of the proposed laser is obtained by simulating the transmission spectra.When the total current is 130 mA,the simulated laser wavelength drift can reach 4.2 nm.We have fabricated a semiconductor laser with the proposed structure,and the experimental results proves that the phase shift can be induced by changing the injection current ratio.When the total current is 130 mA,and only the ratio of the injection current between the central electrode and the two sides of the electrode is changed,we can see the stable wavelength drift of 1.2 nm under single mode excitation,and the side-mode suppression ratio is greater than 42 dB.However,if the current of the side electrode is fixed and only the current of the central electrode is changed,the phenomenon of mode stability conversion is also observed.This phenomenon is consistent with the results of theoretical calculation,which proves that the equivalent phase shift and distributed phase shift can affect the laser-mode at the same time.In addition,we also briefly discussed the laser manufacturing process and packaging process.