A Novel Mach-Zehnder Interferometer Using Eccentric-Core Fiber Design for Optical Coherence Tomography.

Qiao Xiong,Pengfei Wang,Xinglin Tong,Fang Liu,Chengwei Deng,Cui Zhang,Zhiyuan Zheng

doi:10.3390/s18051540

Abstract

A novel Mach-Zehnder interferometer using eccentric-core fiber (ECF) design for optical coherence tomography (OCT) is proposed and demonstrated. Instead of the commercial single-mode fiber (SMF), the ECF is used as one interference arm of the implementation. Because of the offset location of the eccentric core, it is sensitive to directional bending and the optical path difference (OPD) of two interference arms can be adjusted with high precision. The birefringence of ECF is calculated and experimentally measured, which demonstrates the polarization sensitivity of the ECF proposed in the paper is similar to that of SMF. Such a structure can replace the reference optical delay line to form an all-fiber passive device. A mirror is used as a sample for analyzing the ECF bending responses of the system. Besides, four pieces of overlapping glass slides as sample are experimentally measured as well.

Highlights

Optical coherence tomography (OCT) is a tomographic imaging technique with micron-scale resolution, which has revolutionized biomedicine since its introduction to imaging biological tissues such as human skin, retina and blood vessels [1,2,3,4]
Time domain optical coherence tomography (OCT) requires adjusting the length of the reference arm for real-time imaging
Fourier domain OCT requires setting the length of the reference arm for phase match with the sample arm and depth scanning [10]

Summary

Introduction

Optical coherence tomography (OCT) is a tomographic imaging technique with micron-scale resolution, which has revolutionized biomedicine since its introduction to imaging biological tissues such as human skin, retina and blood vessels [1,2,3,4]. Time domain OCT requires adjusting the length of the reference arm for real-time imaging. Fourier domain OCT requires setting the length of the reference arm for phase match with the sample arm and depth scanning [10]. Kushal et al reported a swept-source OCT system for pediatric bronchoscopy and they adjusted the reference arm delay length for providing a relative delay [11]. The optical path length of the reference arm was adjusted by the preset reference mirror position as precisely as less than 0.1 micrometers. Instead of the commercial single-mode fiber (SMF), the ECF is used as one interference arm of the implementation. Commercial single-mode fiber (SMF), the ECF is used as one interference arm of the implementation.

Theory

Experimental Setup

Results

Conclusions