| Optical orthogonal frequency division multiplexing (OOFDM) is a multiplexing technique from wireless, it has high spectral efficiency and capability to resist chromatic dispersion. Furthermore, this technique can reduce the dependence on electronic chips and decrease the cost of OFDM system. These advantages make it has been widely researched.Firstly, the principle of OFDM is explained, and the theory of OOFDM chips is obtained on the basis of optical coupler theory. Then the electrode to achieve phase shifting caused by thermo optical effect is designed.Secondly, the algorithm of proportion integral derivative (PID) controller is explained in mathematics. After this, the method to deal with actual chips, the principle of electric circuit, the structure of processor and the environment of programming are introduced. Based on this, the general framework, every model and the notes in programming are demonstrated in details. In addition, this thesis designs the serial port software with nice interface to communicate with micro processor.Finally, the software control system is used to induce phase shifting on 2×10G OOFDM multiplexer. These are two steps in test parts: the program is firstly debugged on a useless chip and the control accuracy is about±0.1℃. After being applied to the OFDM chip, the control circuit is tested by a wide spectrum light source. The shift of standard wavelength is 0.08nm when the temperature of the chip increases 23℃under the condition of room temperature(22.5℃). At last, measured results show that this software control system can work effectively. |
PDF Full Text Request