SOI-Based Multi-Channel AWG with Fiber Bragg Grating Sensing Interrogation System

Siming Weng,Pei Yuan,Lianqing Zhu,Wei Zhuang,Dongliang Zhang,Fei Luo

doi:10.3390/photonics8060214

Abstract

For the development of minimized and high-rate photonic-integrated fiber Bragg grating interrogation (FBGI) systems, arrayed waveguide grating (AWG) has been widely used as one of the critical components. In this paper, we present an 8-channel SOI-based AWG for a photonic integrated FBG interrogation microsystem. The channel spacing of the AWG is designed to be 3 nm to meet a high-dynamic-range demodulation requirement. The core size of the fabricated AWG is about 335 × 335 μm2. The simulation results and experimental results are in high agreement, showing that AWG has a fine transmission spectrum with crosstalk below −16 dB, nonuniformity below 0.4 dB, insertion loss below −6.35 dB, 3 dB bandwidth about 1.3 nm and 10 dB bandwidth of 2.3 nm. The proposed AWG can be applied perfectly to the SOI-based AWG demodulation microsystem, exhibiting a large dynamic range of 1.2 nm, the resolution for measurements is 1.27 pm and a high accuracy of 20.6 pm.

Highlights

To monitor the structural health and external environment of civil engineering, rail transit, aerospace, etc., and to ensure their safe operation, many kinds of sensors have been developed and widely used, one of which is the fiber Bragg grating (FBG) sensor [1,2,3,4,5]
The existing commercial fiber Bragg grating interrogation (FBGI) based on discrete optoelectronic components, such as dynamic matched grating filters, tunable Fabry–Perot filters, CCDs, usually limit the development and application of FBG sensing technology because of their inferiorities in size and demodulation speed [4,11,12,13,14]
arrayed waveguide grating (AWG)-based photonic-integrated FBGI systems have gained attention because of their advantages of a compact structure, energy efficiency, and the possibility to realize high-speed interrogation, because the interrogation rate of the FBGI system is only affected by photodetector (PD) response time and AD sampling rate

Summary

Introduction

To monitor the structural health and external environment of civil engineering, rail transit, aerospace, etc., and to ensure their safe operation, many kinds of sensors have been developed and widely used, one of which is the fiber Bragg grating (FBG) sensor [1,2,3,4,5]. The central wavelength of the FBG’s reflected spectrum will shift with the variation of the environment, such as temperature, pressure, ultrasonic, etc. These physical parameters can be detected by demodulating the FBG wavelength.

Results

Conclusion