Develop Small Spot Mini Gain Flat Filter

Signal amplified by EDFA exist different gain, which will cause error.So it isnecessary to add a gain flat filter to gain the signal. Miniaturized devices become atrend along with the market development. This paper designs a small gain flat filteraccording to technology of common Gain Flat Filter.First it introduces the application and background, several different technologiesand index conditions of Gain Flat Filter. It introduces the preparation principle andtechnology of the medium thin film filter. It calculates the relationship between thewavelength and incident Angle of the medium thin film filter in theory. The incidentangle is smaller, the wavelength greater. We can change the angle to control thewavelength shift, which provides the basis for design and produce.I get the conclusion from calculating the coupling efficiency of collimator gaussbeam——the key factor of increase IL is angular mismatch.And angular mismatch isrelated to size of spot.Smaller spot have smaller angular mismatch. This paperdevises a new small spot mini collimator combined with conclusion above andprinciple of C-lens.In theory, GFF have good performance assembled by this newcollimators.This paper designs two kinds of structure of small gain flat filter. I chose thestructure by parameter contrast, which has smaller waist radius、more stable structureand more simple process, The final size of the package is3.2*31mm.This article makes work flow and standards,proves small amount.Data indicatethis structure having little IL and stable TDL.Meanwhile I carry out reliabilitydemonstration such as beat、DH、TC. It does pass validation which proves thisstructure is feasible and satisfying for design requirement.This new gain flat filter passes the production feasibility verification andreliability validation, can batch production, achieve the design purpose.