The Study Of HPDLC Grating And Its Application On EDFA Dynamic Gain Equalization

As the key module of fiber optics network, EDFA (Erbium Doped Fiber Amplifier) is developed with the advance of the performance of network. However, the unbalanced gain of cascaded EDFAs will lead to cross talk, unstabliztion and high error rate. So it is necessary to equalize the gain spectrum of EDFA to realize long distance data transfer.The properties of diffraction light, transmission light and driving voltage of HPDLC (Holographic Polymer Dispersed Liquid Crystal) are researched experimentally in both 1550nm and 632.8nm laser. It is proved that the HPDLC has good property in 1550nm infrared laser and it is suitable to be used in the application of fiber communications. The EDFA dynamic gain equalizer based on HPDLC grating is developed according to the character of HPDLC grating's transmission spectrum. And a compensated EDFA gain spectrum is get to flatten the EDFA in C-band. The index modulation of HPDLC grating is electrically switchable, and this help to design the dynamic gain equalization system. The system is designed using MCU to control the voltage on gratings respectively. It provides a good way to solve the problem in EDFA gain flattening.Using HPDLC gratings as gain equalizer of EDFA is a new method, which has many merits as small volume, quick response, good flatness and suitable for the application under the temperature drift. Meanwhile, simulation via computer can support the manufacture of gain equalizer. Also it helps to reduce the cost and developing time.