Study On Optical Fiber Characteristic Measurement Technology In Mode Division Multiplexed Optical Fiber Communication System

In recent years,optical fiber communication has been used as a major technology to increase the capacity requirements of the communication system and been extensively researched and developed around the world.However,with the rapid growth of various data services,such as the Internet,online games etc.,optical fiber communication system must be timely updated by using new technologies to improve the transmission data rate and system capacity.Recently,the modedivision-multiplexing(MDM)based technology as one of the promising technology,has been widely adopted to achieve the large capacity transmission systems.In general,the few-mode-fiber(FMF)is the key component of such MDM-based optical fiber communication systems.Consequently,the properties of the used FMF including the modal dispersion and differential mode group delay(DMGD)will have an important impact on the performance of the transmission systems.Thus,it is essential to characterize the FMF to further optimize the system performance.In this paper,we propose a novel scheme based on the spectral interference method to measure the modal dispersion characteristics of a long FMF.The modal dispersion parameters of the measured FMF can be directly obtained after a simple fast Fourier transform(FFT)processing to the interference data.Meanwhile,the precision of ± 0.0015ps/m for DMGD measurement has been achieved.The proposed method has the advantages of simpler configuration,faster measurement speed and better measurement accuracy compared with other methods.Based on this,we propose an improved characterization scheme in combination of optical frequency comb,and the measurement performance of this method is studied experimentally.In summary,the characterization method for FMF has the potential to find the applications in the MDM-based large capacity optical fiber communication systems.