Wideband Microwave Frequency Distribution for Multi-access along a Single Fiber Link

In this paper, a fiber-optic signal access method is proposed for stable wideband microwave frequency distribution. Incorporating with the tapped counter-propagating reference signals and variable optical delay lines (VODLs), a stable wideband microwave frequency signal can be obtained at any access point (AP) along the main fiber link. Moreover, all the phases of received wideband microwave frequency can be aligned. In this way, the whole system complexity can be dispersed as the central station only stabilizes the main fiber link delay, and the access ends (ANs) operate independently. Experimentally, a multi-access wideband microwave frequency distribution is demonstrated over a 50 km dispersion-compensated fiber link. A system figure of merit is investigated in detail. The results show that the fiber-optic wideband microwave frequency transmission system can operate for the frequency over 40 GHz. The additive phase noises of −125 dBc/Hz for the remote end (RN), and −131 dBc/Hz for the AN, respectively, are achieved at the 1 kHz offset frequency for a 1 GHz frequency signal. Thanks to the active delay stabilization, the Allan deviation (ADEV) of 1.3 × 10−13 /s and 2.4 × 10−15 /100 s for the RN, and the one of 8.8 × 10−14 /s and 4.4 × 10−15 /100 s for the AN, respectively, are acquired.