利用接收端光單旁波帶濾波器改善有線電視系統CSO、CTB失真

To Improve CSO/CTB Performances Employing Optical SSB Filter at the Receiving Site

陳相志(Hsiang-Chih Chen)

指導教授 ： 呂海涵 教授

國立臺北科技大學/機電學院/光電工程系所/碩士(2005年)

https://doi.org/10.6841/NTUT.2005.00214

摘要

在本論文中，我們提出三種光纖有線電視系統架構，探討經過長距離傳輸後光纖有線電視系統的傳輸特性。在第一個架構中，我們提出一個外調式滿載77頻道的長距離光纖有線電視系統，系統的總傳輸距離為100公里，我們在接收端利用光單旁波帶濾波器降低雷射光譜線寬，和傳統傳輸100公里單模光纖的外調式光纖有線電視系統相比較，此系統可以獲得較出色的載波雜訊比、二次合成失真及三次拍差失真。第二個系統架構是以分頻多工技術及接收端光單旁波帶濾波器所建構而成的直調式滿載77頻道長距離光纖有線電視系統，經過120公里的單模光纖傳輸之後，此一系統可獲得良好的載波雜訊比、二次合成失真及三次拍差失真傳輸參數。最後，我們以分頻多工技術、外部光源注入技術及接收端光單旁波帶濾波器建構一長距離直調式Fabry-Perot雷射二極體的光纖有線電視系統，我們利用外部光注入技術及接收端光單旁波帶濾波器提升Fabry-Perot雷射二極體的傳輸特性抑制光纖色散的不良影響，在經過100 公里的單模光纖傳輸後，此系統可獲得較佳的有線電視傳輸參數。在我們所提出的這三套系統架構，雖然光信號是以雙邊帶調變的形式傳送，但我們證明了接收端的光單旁波帶濾波器可減少雷射光譜線寬，改善由光纖色散所造成的系統參數劣化，提升系統的傳輸參數值。

關鍵字

掺餌光纖放大器 ； 光單旁波帶濾波器 ； 光譜線寬 ； 載波雜訊比 ； 二次合成失真 ； 三次拍差失真 ； 分頻多工技術

並列摘要

In this paper, We proposed three fiber optical CATV systems. First, we proposed and demonstrated an externally modulated NTSC 77-channel erbium-doped fiber amplifier (EDFA)-repeated system employing optical single sideband (SSB) filter at the receiving site. In comparison with conventional externally modulated fiber optical CATV systems over a 100-km single-mode fiber (SMF) transport, excellent performances of carrier-to-noise ratio (CNR), composite second order (CSO), and composite triple beat (CTB) were achieved for the full channel band over a 100-km SMF transport. Second, a directly modulated AM-VSB CATV EDFA-repeated system that uses split-band technique and optical SSB filter at the receiving site is proposed and demonstrated. Good performances of CNR, CSO and CTB were achieved for the full channel band over a-120 km SMF transport. Third, a AM-VSB CATV EDFA-repeated transport system based on directly modulated Fabry-Perot laser diode (FP-LD) using external light injection technique, split-band technique and optical SSB filter at the receiving site is proposed and demonstrated. We use external light injection technique and optical SSB filter at the receiving site to improve the performance of FP-LD and reduce chromatic dispersion effect. Good performances of CNR, CSO and CTB were achieved for the full channel band over a-100 km SMF transport.

Though the transmission format is optical double sideband (DSB) format, we verify that our proposed simple filtering technique can ameliorate the fiber dispersion by reducing the spectral linewidth at the receiving site. Our proposed system is suitable for the fiber optical CATV systems in long-haul transport.

並列關鍵字

erbium-doped fiber amplifier ； single sideband filter ； carrier-to-noise ratio ； composite second order ； composite triple beat ； split-band technique ； spectral linewidth

參考文獻

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