Fiber Coupler Manufacturing Equipment

The thesis presents a method to enlarge the dynamic range and improve accuracy of low optical signal for manufacturing equipment of fusing fiber coupler, by using Log Amplifier with software and hardware modifications.In the fusing optical coupler process, the uncertainties like fiber thermal inertia, mechanical inaccuracy, ambient temperature changing and airflow disturbance make it difficult to get a precise performance on coupling ratio and insertion loss. These uncertainties are more critical to the manufacturing of optical coupler with low coupling ration. In practice, the issue disturbs the approach to higher yield rate and eventually, harms the competitive power in the market.From the view of modifying and improving fusing optical coupler workstation, the thesis introduces the theory and manufacturing process of optical coupler, with a survey on the history and actuality of the device. Two models used to analyze optical coupler are introduced, as well as the parameters and typical values used to characterized the device. Further, the thesis compares the fusing optical coupler with PLC splitter. The thesis also presents the experiment and analysis to demonstrate the effects on water peak loss, caused by using Hydrogen and Oxygen flame in the fusing process.Specifically, the thesis discusses the coupler manufacturing equipment on the elongating motion control, Hydrogen-Oxygen flame fusing and packaging technique. The hardware and software approach to control fusing temperature profile by pre-setting mass flow rates of H₂ and O₂ are demonstrated in detail. The modifications on motion control and quartz tube temperature control for better epoxy curing are also addressed.To optimize the OE converting performance, a Log amplifier is introduced to enlarge the dynamic range and improve low optical converting accuracy. The optical performance of Log Amplifier is compared with that based on linear amplifier circuit. The method to eliminate the optical and electrical noises is discussed, following by the algorithm modification on coupling cycle counting. The experiments are documented and carefully analyzed. The upgraded equipment can fulfill the requirement for 0.1% optical coupler production and have a dynamic range larger than 33dB.At the end of the thesis, the works to optimize the coupler manufacturing equipment are summarized, with the forecast to further actions.