Research On Reducing Slow Optical Transmission Loss In Erbium-doped Fiber By Using Cascade Structure

The slowing down of the transmission of light has become a hot topic of research in recent years,attracting the research interest of most scholars and experts.As we all know,the transmission speed of light is 2.99792458×108 m/s,which is the fastest speed in the universe,and it has been transmitted at an unchangeable speed.Before the optical signal was studied by people,electrical transmission was a very important signal transmission method,which was later replaced by it.Compared with electrical signals,optical signals have a wide transmission range,carry a large amount of information,and are less susceptible to interference.In recent years,people have been working on the slow light theory in nonlinear optical crystal materials.The materials used are thulium-doped fiber,ytterbium-doped fiber,ruby,alexandrite crystal,and erbium-doped fiber,etc.,and slow light phenomenon appears in these materials.But in fact,the energy of light attenuates to a certain extent after a certain amount of transmission,which limits the development of slow light transmission technology to a large extent.The emergence of Erbium Doped Fiber Amplifier(EDFA)can just make up for the problems caused by optical power loss.Therefore,the EDFA is used to amplify the power of the optical signal in the transmission process to achieve higher efficiency in the application.Compared with other methods,erbium-doped fiber has the advantages of room temperature operation,controllable delay,small device size,simple device and high-efficiency detection.It has a promising future.This article is mainly aimed at the theoretical analysis of optical power amplification using EDFA on the basis of ensuring the slow light time delay for simulation and simulation calculation.Therefore,it is necessary to study some practical application issues,such as the relationship between the output signal optical power and the placement of the pump,and some parameters of the pump and optical fiber.The specific research content of this article includes:Briefly introduce the relevant parameters of slow optical transmission loss.The basic theory of slow optical transmission loss is briefly explained.According to the Coherent Population Oscillation(CPO),the three-level system of erbium ions is selected,and starting from the metastable rate equation and transmission equation of erbium ions,the erbium-doped cascade structure of 1480 nm and 980 nm mixed pumps is reduced.The speed of light under the optical fiber slows down the transmission loss for theoretical research.Based on theory,by discussing the gain curve of erbium-doped fiber with 1480 nm and 980 nm hybrid pump cascade structure,it is possible to better judge whether the erbium-doped fiber medium is in the absorption state or the gain state,so as to judge whether the speed of light is slowed or advanced spread.Then compare the power loss of 1480 nm and 980 nm hybrid pump cascade structure erbium-doped fiber,and 1480 nm and 980 nm hybrid pump single erbium-doped fiber structure.It is concluded that as the pump power ratio(Pump ratio,PR=P1480:P980)increases,the power loss generated by the former is smaller.By changing the placement mode of the erbium-doped fiber pump of the 1480 nm and980nm hybrid pump cascade structure,the obtained output signal optical power is also significantly different.It is concluded that the optical power of the output signal placed before the erbium-doped fiber with a hybrid pump cascade structure of1480 nm and 980 nm is higher.This results in a smaller loss factor and a larger time delay.When the pump power ratio is 1,1480 nm and 980 nm hybrid pump cascade structure erbium-doped fiber is placed before the structure,the length ratio(Length ratio,LR=L1:L2,where L1,L2 represent 1480 nm and 980 nm respectively When the first-stage fiber length and the second-stage fiber length in the hybrid pump cascade structure erbium-doped fiber are smaller,the output signal optical power becomes larger,and the signal optical loss coefficient is correspondingly small.Finally,a new structure is proposed for optimizing slow optical loss-dual 1480 nm hybrid pump cascade structure erbium-doped fiber.Through comparison and analysis,it is found that the dual 1480 nm hybrid pump cascade structure erbium-doped fiber can reduce the output signal optical power loss.The performance is more obvious.