Research On Super-broadband Fiber Amplifier

The erbium-doped fiber amplifier (EDFA) is emerging as a landmark in the history of the development of optical fiber communications, and it accelerates the development of WDM/DWDM (Wavelength Division Multiplexing/Dense WDM) communications systems. At the same time, there appears some further demand to the EDFA as the development of WDM/DWDM, such as the broad bandwidth, automatic gain control and automatic power control.The traditional EDFA has the bandwidth of 35 nm from 1525 to 1560 nm, which only partly cover the transmission window from 1450 to 1650 nm of single mode fiber. With the development of WDM, it is more and more important to increase the bandwidth of optical fiber amplifiers. Recently, the research of L-band (1570~1620nm) erbium doped fiber amplifiers (EDFA) and S-band (1450~1510nm) thulium doped fiber amplifiers (TDFA) has become one of the hotspots in devices research of optical communication.In this paper, we summarize the basic theory and developmental status of fiber amplifiers, introduce the experimental research of L-band EDFA and S-band TDFA, and also describe the gain control of C-band EDFA and the experiment of regenerative erbium doped fiber ring amplifier. The research works in detail is the following:1. Introduce the three energy level of EDFA and deduce the rate equation for population changes and propagation equation for pump and signal beams.2. Adopting bi-directional pump of 980nm LD and 1480 nm LD, by the reflection of fiber loop mirror (FLM), we get a kind of novel super-fluoresces fiber source with ultra bandwidth and high output power. The bandwidth of ASE is 76.6 nm from 1524 to 1600.6 nm, which covers the communication window of C+L band. The total power of ASE is 22.1 mW and the conversion efficiency is 18.8%.3. The L-band signal amplifier had been achieved using two different schemes based on using backward ASE as pump resource. To the small signal at 1575 nm, the gain is 3.5 dB and 9.2 dB respectively.4. Using backward ASE as the second pump by the reflection of FLM, we get a kind of novel L-band EDFA. Compared with directional pump, the enhancement of flattened gain and output power is 5.33 dB and 3dB respectively.5. By reflecting C-band ASE with FLM, adding 980 nm LD at the input port and adjust power ratio of 1480 and 980 nm LD, during the range from 1565 to 1615 nm, the gain of the bi-direction pumped reflection L-EDFA are enhanced by 1.5-9.4dB, and the NF are descended by 1.3-9.4dB.6. The amplification characteristics of thulium-doped fiber amplifier (TDFA) have been studied using the basic theory of fiber amplifier. The connection between the thulium-doped fluoride fiber and silicon fiber is accomplished, and we study the TDFA and the reason that the expecting results haven't been achieved has been analyzed. The assumption of the Er-Tm co-doped silicon fiber has been presented, and we study the Er-Tm co-doped silicon in...