Minimization of splice loss between a single mode fiber and an erbium doped fiber

The recent increase in the demand for higher bandwidth and transmission of data over longer distances has increased the demand for optical networking products like Erbium Doped Fiber Amplifiers (EDFAs). An EDFA is primarily used in long haul transmissions to amplify the weak optical signals. It involves the use of Single Mode Fibers (SMFs) and Erbium Doped Fibers (EDFs). Several issues are involved in the assembly of these fibers that is primarily carried out by means of fusion splicing. Studies indicated that the splicing of an SMF to another SMF is less sensitive to fusion splicing parameters, if they are selected within appropriate range. The losses obtained during the splicing of an SMF-SMF are small enough ('acceptable') i.e. they are within the prescribed loss budgets. However, splicing of dissimilar fibers such as an SMF to an EDF poses a new set of requirements on the splicing specifications. Due to the variation in physical properties of the two fibers, the splice loss between them is much higher as compared to that obtained between SMF-SMF. Such high losses accumulate at the end of the assembly process and could exceed the loss budgets specified by the OEM. Manufacturers of fusion splicers provide customized programs for splicing an SMF to an EDF. However, significant variation in the loss values had been observed between different batches of EDF. Although customized programs are available for this purpose, they need to be validated for different batches of EDF. This is a concern in the manufacturing environment, especially in an Electronics Manufacturing Service (EMS) provider's facility. Consequently, the objective of this research endeavor was to develop a systematic procedure to minimize the losses between an EDF and an SMF. The loss between an SMF and an EDF is a function of various splicing parameters. These parameters were identified through statistically designed experiments. Significant parameters were screened out and their interactions were studied. The aforementioned experiments and their results are discussed in this paper. Through this research effort, a systematic procedure for evaluating an EDF and identifying the parameters that could be used for a specific batch of fibers was developed. Guidelines for the characterization process are also discussed.