The Design And Fabrication Process Of Glass-based Ion-exchange Optical Power Splitter

Ion-exchange is a traditional effective method for manufacturing glass-based waveguides. Comparing to other glass-based waveguides manufacturing method, Ion-exchange is low cost, low propagation loss, compatible with fiber, low internal stress, environmental stability, even capable for doping Er+ optic amplifier. Ion-exchange is a good choice for mass manufacturing of passive optical device.Optical power splitter is a basic device used in PON(Passive Optical Network). Its performance indicators include insertion loss, uniformity, PDL(Polarization Dependence Loss), environmental stability.Through investing the microstructure design of the optical power splitter, this paper proposed three key points:1st. the selection of the curvature radius,2nd.Y-branch design precautions, and 3rd. the length of straight waveguide before the Y-branch. The 1st and 2nd points influence device length and insertion loss. The 3rd point influence the uniformity of the power distribution.Using typical single-mode waveguide Ag+-Na+ exchange process, this paper have measured relationship of waveguide radius and insertion loss.We have improved design of 1X8 splitter, shortened the device to 12.5 mm while keeping good performance. Experimental results have proved the design successful. The fabricated device is low insertion loss as less as 10 dB, good uniformity as less as 0.3 dB. The reference straight waveguide’s insertion loss is as less as 0.5 dB.We have also improved design of 1×16 and 1×32. Length of improved 1×16 device is 15 mm. Length of improved 1×32 device is 24 mm.The process is controllable, good tolerance, good repeatability. In order to get qualified device, we may keep the waveguide single-moded, narrower than 8μm, deeper than 14μm.