Research On The Gain Characteristics Of Fiber Optical Parametric Amplifiers

Future optical communication systems need optical amplifiers with wide flat gain, also with wavelength conversion and optical reshaping functions. Fiber optical parametric amplifiers (FOPA) which take the high nonlinear fiber (HNLF) as its gain medium can fulfill this multifunction requirements.FOPA has the potential of providing several hundred nanometers flat gain bandwidth. However, the FOPA gain characteristics are affected seriously by the zero dispersion wavelength fluctuation due to the imperfectness of the fiber. Research on the gain characteristics of the FOPA will provide inspiration for designing new ways to optimize the FOPA.(1) The small gain characteristic of the single pump FOPA has been studied; also, factors influencing the gain and bandwidth are investigated in simulation. Beyond that, the noise characteristics have been analyzed simply in the end.(2) The influence of ZDW fluctuation on the gain characteristics of dual pump FOPA with different pump separations has been studied. Raman Effect is taken into consideration when the wide pump separation FOPA is discussed. Results show that, when the pump separation gets wider, the influence of ZDW fluctuation gets more serious. Particularly, FOPA becomes much more sensible to the ZDW fluctuation with Raman Effect. Raising the pump power is a good way to depress the ZDW fluctuation.(3) Gain characteristics of FOPA with an OBPF inserted has been investigated. The proposed inserting an OBPF scheme is completed and validated in the single pump FOPA. Simulation results show that the pump power conversion efficiency can be improved by about30%. While apply the scheme in the dual pump FOPA, we cannot get the expected gain improvements. In fact, half of the bandwidth has lost. In conclusion, inserting an OBPF in the FOPA has its limitation, it is not suitable for the dual pump FOPA.