40Gbps NRZ transmitted over 500km based on broadband dispersion compensation CFBG

Using broadband dispersion compensation CFBGs, over 500km-4OGbps NRZ transmission system on G.652 fiber will be demonstrated without electric regenerator, FEC and Raman amplifier. The power penalty is about 2dB @ BER =10(-10).The CFBGs have better performance: 3dB band is about 1.2nm, group delay ripple is less than 25ps near center wavelength, power ripple is less than 2dB, and DGD is less than 1ps. In order to stabilize the DC bias of the LiNbO3 MZ modulator, a semiconductor cooler is applied to control the temperature. The effect is perfect.