Research On DPSK Signal Application Of Polarization Rotation In Cascaded SOAs

With advantages such as lower noise, dispersion insensitivity and suitable for long distance transport, DPSK signal has been widely used in all optical communication network in recent years. SOA has advantages like strong nonlinear effect, small size, adjustable gain spectrum width, fast response speed and integratable, and has gradually become a key device in the study of optical signal processing. At present, all-optical signal processing based on the nonlinear effect of SOA has become a hot research topic. Although the research of DPSK signal processing based on SOA’s nonlinear polarization rotation effect is of great significance in the development of optical communication network but relatively rare. This thesis mainly focuses on the application of SOA’s polarization rotation on DPSK signal processing and the main works are as follows:1. By the study on of the nonlinear polarization rotation effect of single SOA, we got the curve of SOA’s nonlinear polarization rotation degree along with the change of control light’s power, under different input signal light power and different input current. We can learn from the curve that the smaller the input optical power and the larger the input current is, the greater the nonlinear polarization rotation effect of SOA along with the change of control light’s power is.2. According to the problem of the insufficient of NPR effect in single SOA, the method of using cascaded SOAs system to imrpove NPR effect which was based on the invention of cascaded SOAs’PSP alignment method. And the feasibility of this method is verified by the experiments.3. After the aligment of cascaded SOAs’principle state of porlarization, the study of cascaded SOAs’ the nonlinear porlarization rotation effect was done and the curve of nonlinear porlarization rotation degree along with the change of control light’s power was obtained.4. A all optical switch structure based on the NPR effect in two cascaded SOAs was proposed. And an experiment based on this structure is conducted after the aligment of cascaded SOAs’principle state of porlarization. The swiching speed of this all optical switch is200ps.5. The header extraction of DPSK signal is realized by using the all optical switch structure based on the NPR effect in two cascaded SOAs.