Impact of Amplitude Noise in Millimeter-Wave Radio-Over-Fiber Systems

Abstract

In this paper, a complete theoretical and experimental study of amplitude noise impact on performance of radio-overfiber (RoF) communication system in millimeter-wave (MMW) frequency band is presented. A simulation method is also presented, using which one can determine the origin of the amplitude noise which has the most impact on error vector magnitude (EVM). This method is based on analyzing the trends of EVM versus received optical power. The impact of different optical and electrical noise such as relative intensity noise, shot noise and thermal noise on EVM is precisely studied employing experimental and theoretical analysis. In the proposed RoF system, two techniques are used to generate MMW signal, and the EVM results are compared from amplitude noise viewpoint. In the first technique, two independent distributed feedback lasers are used to generate MMW signal at the output of a photodetector, and the second technique is based on a passively mode-locked laser diode. Impact of optical sources phase noise on performance of the system is removed using a noncoherent down-conversion method based on envelope detector. Using this method, a very good matching between the experimental and the simulation results is observed.Index Terms-Distributed feedback (DFB) laser, envelope detector, error vector magnitude (EVM), millimeter wave (MMW), passively mode-locked laser diode (PMLLD), phase noise, radioover-fiber (RoF), relative intensity noise (RIN), shot noise.

Impact of Laser Mode Partition Noise on Optical Heterodyning at Millimeter-Wave Frequencies

“…Similar result can be observed by detecting a signal in a system where no mode partition noise exists, measuring beating between two independent mono-mode lasers, e.g. distributed feedback laser [15], [16]. Fig.…”

“…When using the mixer, a local oscillator (LO) at 52 GHz downconverts mm-wave signal to 6.63 GHz. Since an envelope detector only detects intensity, the noise detected is due to sum of RIN and LMPN in a PSD of photocurrent, and thus there is no impact of phase noise on beating signal [15], [16].…”

“…The influence of phase noise on mm-wave and sub-THz RoF system was investigated [11]- [13]. We also demonstrated the impact of relative intensity noise (RIN) on the generation of mm-wave signals for two different kinds of lasers, and an envelope detector (ED) was proposed to only detect the intensity noise on mm-wave [14]- [16] and W band signals [17]. The use of multi-mode sources can lead to larger power fluctuations in each mode due to laser mode partition noise (LMPN) with relatively constant total optical power from source.…”

Relative intensity noise in optical heterodyning applied to millimeter-wave systems

“…Depending on the heterodyne process, RIN at MMW signal can be larger than the initial RIN at low frequency and causes spectral degradation in optical heterodyne signals. For RoF communication systems in MMW range, RIN impact on generated MMW signals can be observed by measuring Error Vector Magnitude (EVM) after suppression of phase noise effect by using an envelope detector at the receiver [7]. In this paper, due to system stabilization and applications in MMW, we have used two techniques for optical heterodyne generation.…”

Co-integration of two DFB lasers on glass for millimeter-wave generation

“…L'inconvénient de l'utilisation des lasers à blocage de mode est leur sensibilité aux contre-réactions et leur grande largeur spectrale, qui rend le système sujet à la dispersion dans les fibres optiques et conduit à un évanouissement périodique du signal pour certaines longueurs de fibre [2]. Le battement optique a été déjà réalisé avec des lasers à semiconducteurs, mais cette technologie présente certains défauts, dont une largeur de raie importante et un pic de bruit d'intensité situé à des fréquences de quelques GHz, pouvant atteindre les bandes de modulation [3]. Pour réduire ces impactes, des boucles à verrouillage peuvent être utilisées ce qui complexifie le système.…”