光纖放大器及光纖光柵組成裝置之研製及其於分波多工光通信系統之應用

Abstract

此篇博士論文分為三部份: 第一部份我們研製並討論兩種特殊用途之光纖放大器，對增益等化光纖放大器，藉由加入一段自製摻釤光纖或一些短週期光纖光柵來完成設計，我們亦探討此類光纖放大器之特性與品質。對於光額定放大器，嘗試以多工濾波器或光纖光柵結合光迴旋器作為主體製成，實驗證實以多工濾波器製成之光額定放大器，在OC-48傳輸速率下，於環形網路中可以有150公里之光纖間距，而光纖光柵結合光迴旋器製成之光額定放大器，對於因放大信號之背向反射所引起的功率償付效應亦加以探討與分析。 第二部份我們提出利用光纖光柵組成之三種裝置及其應用，它們分別是多波道光纖雷射、信號塞取器及光切換器，它們可以廣泛應用於光纖環形網路與光纖通信系統。第四章我們提出多波道光纖雷射之架構，包含動態波長可選之環形共振腔式，及並聯泵激之線性共振腔式，藉由參數調整或加入泵激反射光柵達到波道間功率等化之目的。以光纖光柵結合光迴旋器為元件主要成份，在第六與弟七章提出若干信號塞取器及光切換器之組合架構，它們可廣泛應用於光纖網路中，其有別於或優於傳統信號塞取器與光切換器之特性亦加以比較及描述。 第三部份，藉由商用光纖放大器補償光纖傳輸損失，本文展示若干單向及雙向傳輸系統實例。對單向傳輸子題，我們從事一類比與數位混成傳輸之分波多工系統實驗，並探討數位與類比信號分別對串音之容忍度。對雙向傳輸子題，利用成對多工濾波器，我們從事雙向信號塞取與雙向傳輸之架構設計與實驗。我們也提出兩種利用光纖光柵組成之雙向光纖放大器作為上、下行光信號傳輸之增益介質，而雙向傳輸時因背向反射(特別是雷利背向反射)所引起之功率償付，以及雙向傳輸時多工器與解多工器對串音之容忍度，我們也加以探討。最後我們將對本論文所達成具體成果作簡短結論，並對未來研究方向提出若干建議。

This dissertation consists of three parts. The first part investigates two special erbium-doped fiber amplifiers (EFDA's). In Chapter 2, power-equalized EFDA modules are constructed by inserting a section of homemade Samarium-doped fiber or several short-period fiber Bragg gratings (FBG's) in EDFA. The characteristics and performances of them are addressed. Measured results of the operation dynamic range and gain variation in the 1.55 mm band are provided. In Chapter 3, optical limiting amplifier (OLA) are proposed and discussed. They are based on multiplexer/demultiplexer pair filter or FBG-integrated-optical-circulator (OC). We have experimentally verified that a single WDM OLA can handle a ring size of 150 km at SONET OC-48 channel rate. The impact of back reflection of the amplified signal in the FBG-based OLA is also experimentally verified and theoretically discussed. The second part of this dissertation, including Chapters 4, 5 and 6, proposes three important FBG-based devices for vast applications in optical networks and lightwave system. There are multiwavelength fiber lasers, wavelength add/drop multiplexers (WADM) and optical cross-connect (OXC) devices. The multiwavelength fiber lasers are either a wavelength-selective ring-cavity lasers or pump-sharing scheme, linear-cavity laser arrays. Power equalization among wavelengths is achieved by several methods: inserting micro-benders between adjacent FBG's, using parameter-adjustment, or by adding FBG's into the individual channels as pump reflectors. Based on FBG's and OC's, various approaches are used to construct both the WADM and OXC devices for applications in optical networks. The characteristic of WADM and OXC devices are presented and compared with some conventional designs. The third part of this dissertation, including Chapters 7 and 8, proposes and discusses several experimental configurations for unidirectional and bidirectional lightwave systems. The conventional EDFA's are used to compensate for the fiber loss in each experiment. A hybrid unidirectional WDM system, including both digital and analog channels, is experimentally demonstrated. The crosstalk rejection requirements for such a hybrid WDM system are studied. Based on the using of WDM multiplexer/demultiplexer pair, two novel bidirectional wavelength add/drop and bidirectional transmission configuration are experimentally demonstrated. Two kinds of bidirectional EDFA's based on FBG's are also proposed. Power penalty induced from various back-reflection effects, mainly the Rayleigh backscattering, in a bidirectional WDM system is measured. The crosstalk rejection requirements for a WDM multiplexer/demultiplexer pair in bidirectional lightwave system are also provided. Finally, summary of the research results and suggestion for future work are presented.