Low-noise broadband light generation from optical fibers for use in high-resolution optical coherence tomography

Yimin Wang,Zhongping Chen,Ivan Tomov,Hyungsik Lim,J Stuart Nelson,Frank Wise

doi:10.1364/josaa.22.001492

Abstract

Broadband light generation from a single-mode optical fiber was developed for high-resolution optical coherence tomography (OCT). No noise amplification was observed for light broadened by self-phase modulation. The investigation showed that the intensity noise of light broadened by self-phase modulation in a single-mode optical fiber was much lower than that of continuum light from a microstructure fiber (MSF). The spectral width of a femtosecond input laser pulse was successfully broadened by a factor of 11, and a coherence length of 3.7 microm was achieved with this source. The application of light broadened by a single-mode optical fiber and MSF was compared for use in OCT imaging. The results showed that a single-mode fiber with a small core diameter is a useful way to generate low-noise, broadband light for high-resolution OCT imaging.

Highlights

Optical coherence tomography (OCT) can be used to perform in vivo, high-resolution cross-sectional imaging of microstructures in transparent as well as turbid biological tissues.[1,2] Longitudinal resolution, governed by the source coherence length, is inversely proportional to the light source bandwidth
The investigation showed that the intensity noise of light broadened by SPM in a single-mode fiber was much lower than that of light from a microstructure fiber (MSF)
The imaging ability of light broadened by a single-mode fiber and a MSF were compared

Summary

INTRODUCTION

Optical coherence tomography (OCT) can be used to perform in vivo, high-resolution cross-sectional imaging of microstructures in transparent as well as turbid biological tissues.[1,2] Longitudinal resolution, governed by the source coherence length, is inversely proportional to the light source bandwidth. Superluminescent diodes (SLDs) are often used for OCT imaging and typically have 10– 15 ␮m longitudinal resolution.[3] achieving fast imaging speed with a high signal-to-noise ratio (SNR) requires more than the milliwatt-level power typically available from SLDs. the limited optical bandwidth of SLDs precludes imaging on a cellular level. Nonlinear microstructure fibers (MSFs) can generate an extremely broadband continuum light spectrum from the visible[800] nmto the near infrared1.6 ␮mby using low-energy femtosecond (fs) pulses.[10] This is achieved because of the waveguide dispersion characteristics of the fibers, which shift the zero-dispersion wavelength to shorter wavelengths, and the small core diameters, which provide tight mode confinement.

ANALYSIS

EXPERIMENT

Findings

SUMMARY