Analysis And Optimization Of The Performance In Millimeter-wave Microwave Photonic Photon Link

Millimeter wave photonic link has advantages of small volume, light weight, low loss and anti-electromagnetic interference etc. Meanwhile, the signal of millimeter wave processed in the optical domain is expected to solve the problem of traditional microwave millimeter-wave signal processing ability weak, inefficiency, narrow bandwidth and other electronic bottlenecks. Therefore, millimeter wave photonic link has been extensively concerned and researched. This paper mainly studied the inherent link of millimeter wave photonic without any electrical or optical amplifiers. We analyzed the factors which have influence on the link performance, and then put forward some solutions to optimize and improve link performance on the basis of the inherent link.First, we built a mathematical model of the link, and then introduced some devices in the link briefly, such as MZM modulators, photoelectric detector etc. Some parameters of the link performance were analyzed. Second, this article mainly studied and analyzed the link performance from small-signal equivalent circuit model, some parameters, such as optical power input to the modulator, fiber loss, detector efficiency, and the relative intensity noise of laser ,which affecting the link performances were simulated.From the analysis of the above, we took some measures to optimize performance of the link. Firstly,we used a heterodyne balanced detection method instead of the direct detection of the traditional way. By using this method, it can prove that link performance especially the gain and noise figure of the link have greatly improved. Theory proves that balanced detection can improve the link gain of 6dB, make noise figure reduced 12.3dB. While the simulation software can improve the link gain of about 5dB and make noise figure reduce about 10dB. Secondly, we make use of carrier suppression technique, through the carrier suppression, we can prove that dynamic range of the link can be improved. Meanwhile, optical fiber dispersion has some influences on the transmission system of the millimeter wave, in order to avoid the influences,we adopt single side band modulation method. After that, we connect carrier suppression with single side band modulation, and then have a kind of optimization link with carrier suppression and single band modulation link . Through simulation, it shows that one sideband is inhibited fell 52 dB and carrier is suppressed 36 dB, which greatly increased the dynamic range of the link.Finally, the balance detection together with carrier inhibiting and single sideband modulation technology, a final optimization millimeter wave photonic link-carrier inhibiting single side band modulation balance detection link is established, this link structure not only can greatly improve the dynamic range of the link, but also compared with the single detector concerned, it can make link gain improve 5.8 dB, link noise figure reduce 11.8 dB. So, this structure of the link play optimization and improvement role.