Investigation of EDFA's and FBG-Based Devices and Their Applications in WDM Lightwave Systems
|關鍵字:||光纖放大器;增益等化;光纖光柵;光纖雷射;信號塞取機;光切換器;單向傳輸;雙向傳輸;Erbium-doped fiber amplifier;Power-equalization;Fiber Bragg gratings;Fiber laser;Wavelength add/drop multiplexer;Optical cross-connect device;Unidirectional transmission;Bidirectional transmission|
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.
|Appears in Collections:||Thesis|