Towards photonic innovation: a method of fabricating customizable compact optical fiber delay lines

We present a novel method, to our knowledge, for producing compact optical fiber delay lines (OFDLs) using single-mode fiber (SMF) wound on a 3D-printed spool. By applying a mass-based approach, the SMF length is accurately determined through a fiber mass-length correlation. Results demonstrate strong agreement between the OFDL length obtained via this mass method and traditional optical time-domain reflectometry. Additionally, the experimentally measured delay times align well with theoretical calculations, and the OFDLs show low insertion loss (<1dB), including contributions from ferrule connector/angled physical contact (FC/APC) connectors. This method offers a simplified and potentially scalable solution for fabricating compact OFDLs.