基于超连续谱的全光多通道ROF系统光源的产生

A Super-Continuum Based All Optical Multi-Channel Source Generation in Radio-on-Fiber System

提出一种基于超连续谱梳状切割方案的多通道光载射频传输(ROF)系统光源全光生成方法.实验利用飞秒光脉冲经过2段长5 m、色散符号相反的高非线性光子晶体光纤,在1 550 nm的通信波段产生了带宽超过170 nm的超连续谱.使用本实验室自行设计、制作的取样光纤光栅对所得超连续谱进行滤波,产生了20个波长、峰值波动为±0.3 dBm的多波长梳状光谱,将每2个相邻波长滤出,即可作为ROF系统的一路光载毫米波,共可产生10路.结果表明,所产生的10路光载毫米波峰值波动小,调制深度大,每波长线宽窄,而且整个系统结构简单,插入损耗小,易于集成.

A millimeter-wave-band multi-channel source generating method for wavelength-division-multi- plexed （WDM） radio-on-fiber （ROF） systems is proposed. Firstly, the combined use of a femto-seeond semiconductor mode-locked laser and two 5m-long high nonlinear photonic crystal fibers with opposite dispersion values is demonstrated experimentally to implement a super-continuum with width of more than 170 nm around 1 550 nm. Secondly, a sampled fiber Bragg grating is used to filter spectrum. It is shown that the spectrum is sliced into 20 channels with ± 0.3 dB peak fluctuation. Each two adjacent channels can be filtered out as one channel radio-frequency carrier. 10-channel carriers are successfully obtained for WDM-ROF system. These ten-channel carriers have some advantages such as small gain fluctuation, large modulation depth and narrow width, etc. Besides, the whole system can be easily integrated for its simple structure and small insertion loss.