ROF链路中平衡探测降低RIN噪声的研究
发布时间：2019-05-29 00:46
【摘要】：光载无线传输(ROF)将无线通信技术和有线的光网络技术结合,利用光纤的大带宽、低损耗的特点,在长距离传输中具有很多优势。然而,ROF传输系统中激光器相对强度噪声是制约系统性能的重要因素之一。在数字相干光通信中,平衡探测是降低相对强度噪声的有效手段,对ROF模拟光通信系统具有重要的借鉴意义。本文对ROF传输系统中采用平衡探测降低相对强度噪声的可行性及其影响因素进行了研究,研究内容如下:1.对ROF系统中平衡探测降低相对强度噪声的方法进行了理论分析。证明了可以通过消减直流电流项降低相对强度噪声,但是引入的相位差噪声、本振光强度和相对强度噪声会影响降低的效果。在此基础上在VPI平台上建立了平衡探测模型,并进行了仿真验证,仿真表明ROF链路中平衡探测相比于直接探测降低了相对强度噪声8.6dB/Hz。2.研究了信号光和本振光的功率值,信号光激光器和本振激光器的RIN值,以及信号光激光器和本振激光器线宽值对相对强度噪声降低的影响。VPI仿真验证表明随本振光与信号光功率增加,信号光激光器的RIN值增加和本振光激光器RIN值的降低,系统RIN值会降低。信号光和本振光激光器的线宽值的增加会劣化相对强度噪声的降低效果,但其主要受限于线宽较大的一只激光器。根据这些特性进一步进行了检测信号的仿真分析,对比星座图和计算所得RIN值发现平衡探测系统性能得到了提升。3.对平衡探测中双路失衡的影响进行了研究。对三种失衡因素(传输延时、耦合器分光比和探测器响应度)对降低RIN的影响分别进行了理论分析和仿真验证,结果表明在相对传输延时越小,耦合器分光越均匀,探测器的响应度越接近一致时,平衡探测相比于直接探测能够更有效的降低相对强度噪声,其中传输延时对相对强度噪声的影响具有周期性。当超过一定失衡范围时,平衡探测不能降低相对强度噪声。结合激光器线宽的影响,对双路失衡的容忍范围进行进一步研究,对平衡探测所能容忍的最大延时范围以及探测器响应度之比和耦合系数进行了仿真分析。仿真结果表明随着激光器线宽的增加,平衡探测双路所容忍的失衡范围会明显减小。
[Abstract]:Optical borne wireless transmission (ROF) combines wireless communication technology with wired optical network technology, and makes use of the characteristics of large bandwidth and low loss of optical fiber, which has many advantages in long distance transmission. However, the relative intensity noise of laser in ROF transmission system is one of the important factors that restrict the performance of the system. In digital coherent optical communication, balance detection is an effective means to reduce relative intensity noise, which is of great significance for ROF analog optical communication system. In this paper, the feasibility and influencing factors of using balance detection to reduce relative intensity noise in ROF transmission system are studied. The method of reducing relative intensity noise by balance detection in ROF system is analyzed theoretically. It is proved that the relative intensity noise can be reduced by reducing the DC current term, but the effect of the reduction will be affected by the phase difference noise, the local oscillator intensity and the relative intensity noise. On this basis, a balance detection model is established on VPI platform, and the simulation results show that the balance detection in ROF link reduces the relative intensity noise by 8.6 dB 鈮，
本文编号：2487505
[Abstract]:Optical borne wireless transmission (ROF) combines wireless communication technology with wired optical network technology, and makes use of the characteristics of large bandwidth and low loss of optical fiber, which has many advantages in long distance transmission. However, the relative intensity noise of laser in ROF transmission system is one of the important factors that restrict the performance of the system. In digital coherent optical communication, balance detection is an effective means to reduce relative intensity noise, which is of great significance for ROF analog optical communication system. In this paper, the feasibility and influencing factors of using balance detection to reduce relative intensity noise in ROF transmission system are studied. The method of reducing relative intensity noise by balance detection in ROF system is analyzed theoretically. It is proved that the relative intensity noise can be reduced by reducing the DC current term, but the effect of the reduction will be affected by the phase difference noise, the local oscillator intensity and the relative intensity noise. On this basis, a balance detection model is established on VPI platform, and the simulation results show that the balance detection in ROF link reduces the relative intensity noise by 8.6 dB 鈮，
本文编号：2487505
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