一种中频相同的微波光子信道化接收机

提出一种基于相干光处理的微波信道化接收机,采 用 自由谱范围(FSR)不同的两套光频率梳(OFC,optical frequen cy combs)分别作为 光载波和光本振,使得各个信道的输出具有相同的中频。本文方法将微波信号调制到载波 OFC的每一个 频率分量上,并用法布里-珀罗(F-P)光滤波器对多个信道的调制光边带同时进行带通滤 波,然后与 本振OFC进行相干探测实现频率下转换。若载波OFC比本振OFC的FSR大于1个 信道带宽,并使 F-P滤波器的FSR与本振OFC相等,可得 到等带宽、等中频的微波信道,降低了后续电路的复杂度。对 两个相邻信道进行了实验,将9.74～9.86GHz和9.86～9.98GHz波段的信号分别下转换到两个带宽为120MHz 的中频信道,两个中频信道的中心频率仅相差4MHz分别为900MHz和 896MHz,表明本文方法能够实现等中频的信道输出。

A microwave photonic channelization device with common intermediate frequency

An RF channelizer based on coherent optical processing is proposed.By employing two optical frequency combs (OFCs) with different free spectral ranges (FSRs) as opti cal carriers and optical local oscillators respectively,the channelizer can translate all of the frequency channels to a c ommon intermediate frequency (IF). The microwave signal is modulated on every optical carrier,and then all the mod ulated optical sidebands are filtered by an FP optical filter.Finally,the filtered optical sidebands are coh erently detected with the optical local oscillators,and the frequency down-conversion can be achieved.As the FSR of the carrier OFC is a channel bandwidth larger than that of the local OFC,and the FSR of the FP filter is equa l to that of the local OFC,the channel of common IF and bandwidth can be realized.Therefore,it is convenient for electron ic circuits design.Experiment measurements are demonstrated by translating two adjacent frequency-band range s over 9.74-9.86GHz and 9.86-9.98GHz into a 120MHz IF bandwidth.The center frequencies of two channe ls are 900MHz and 896MHz, respectively with merely 4MHz frequency difference.It is indicated that a comm on IF channel can be accomplished by this method.