| The use of wavelength division multiplexers in optical networks can achieve the goal of making full use of fiber bandwidth resources.Designing high efficiency,low cost,multi-channel wavelength division multiplexers is a trend that is rapidly developing.In this paper,based on the principle of optical path folding,a novel dielectric film type wavelength division multiplexer is designed by using angle tunable filter,and its feasibility and reliability are analyzed.The main contents of the paper include:(1)Design of tunable filter: According to the six standards of channel frequency,insertion loss,bandwidth,isolation,polarization dependent loss(PDL)in the wavelength division multiplexing system released by ITU-T,combined with thin film matrix theory a tunable filter membrane system design system was constructed with the newly constructed evaluation function,and the change of the weighting factors of each parameter can obtain the optimal membrane system for different application requirements.Several membrane systems for LANWDM and DWDM systems have been obtained.The optimal wavelength range of the former is up to 17 nm,and the latter has a maximum tuning range of 12 nm.(2)Design of the optical system: Based on the reflective prism and the angle tunable filter,a multi-channel wavelength division multiplexing system with optical path folding is designed,which can reduce the product volume without changing its optical path.The use of an angle tunable filter enables multiplexing of multiple filters by a single filter,greatly increasing product productivity while reducing cost.(3)Design of the collimation system: According to the collimation characteristics of the curved lens to the Gaussian beam,the spherical collimating lens with the smallest aberration and the aspheric collimating lens are designed.The simulation result of ZEMAX shows that the collimating distance of the former reaches 94.46 mm,the divergence angle is 1.6% before collimation;the latter has a collimation distance of 114 mm and the divergence angle is 1.7%before collimation.(4)Simulation analysis of system reliability: The reliability simulation of the designed system was carried out by ANSYS.The results show that the weak points of the system are mainly distributed in the fiber tail,small prism,collimator bracket and hose.The simulation results of the collimator adhesive shape show that the length of the glue has little effect on the bonding effect;the width of the glue has a great influence on the bonding effect;the optimum bonding adhesive thickness is 0.028 mm.(5)System reliability test: 11 samples were produced for reliability tests such as impact,vibration,high and low temperature cycle and high temperature and high humidity.the product qualification rate is 100%. |
