Photonic Integrated Transmitter for Brillouin Optical Time-Domain Analysis

Abstract

Brillouin optical time-domain analysis (BOTDA) is a powerful distributed fiber-optic sensing technique, widely used in various fields. However, its widespread adoption is hindered by bulky and costly discrete-component systems. Photonic integration technology offers a compelling solution to this challenge. In this paper, we demonstrate a highly integrated BOTDA transmitter, realized through the hybrid integration of an indium phosphide (InP) distributed feedback (DFB) laser chip with a silicon-on-insulator (SOI) photonic integrated circuit (PIC). This in-house-designed SOI PIC comprises three main functional sections: light selection and distribution, pump light generation, and probe light generation. The integrated BOTDA transmitter supports various modulation schemes, while a conventional single-pulse configuration is adopted in this work for system performance evaluation. A Brillouin frequency shift (BFS) uncertainty of (Formula presented.) is achieved over a (Formula presented.) standard single-mode fiber, with a spatial resolution (SR) of (Formula presented.) and 1000 times of averaging. At a higher SR of (Formula presented.), a BFS uncertainty of (Formula presented.) is realized over a (Formula presented.) sensing fiber with 1000-time averaging. To the best of our knowledge, this work presents the first dedicated on-chip BOTDA transmitter, offering a promising path toward compact, scalable, and cost-effective BOTDA solutions.