Hu, D.J.J.; Liu, L.; Dong, H.; Zhang, H. Design of a Broadband Fiber Optic Mode Coupler for Multimode Optical Coherence Tomography. Photonics 2023, 10, 162. https://doi.org/10.3390/photonics10020162
Abstract:
In this paper, we propose an optical fiber-based broadband mode coupler for multimode optical coherence tomography (OCT) in the O-band (1.26-1.36 μm). The proposed device uses a tapered few-mode fiber (FMF) to lower the effective mode index of the selected higher-order mode, which can be phase matched to the fundamental mode of the single-mode fiber (SMF). The tapered FMF and the SMF are side polished to reduce the core-to-core separation to achieve efficient mode coupling. Key design parameters such as the tapering ratio of the FMF, FMF core to SMF core separation, coupler length, and coupling ratio in the O-band are studied thoroughly. Higher-order modes of the FMF will be effectively coupled from the fundamental mode of SMF in the sample arm of the multimode OCT system. The reflected signals of the higher-order modes from the sample will be separated into several single-mode signals using the same fiber device before interfering with the reference light, which was not possible before. The proposed fiber device will be a key component to efficiently achieve multimode OCT operation with better signal collection efficiency and improved penetration depth for deep tissue imaging.
License type:
Attribution 4.0 International (CC BY 4.0)
Funding Info:
This research / project is supported by the Ministry of Health’s / National Medical Research Council - Open Fund Individual Research Grant
Grant Reference no. : MOH-000384
This research / project is supported by the Ministry of Education Singapore - Academic Research Funding Tier 2
Grant Reference no. : MOE-T2EP30120- 0001
This research / project is supported by the Ministry of Education Singapore - Academic Research Funding Tier 1
Grant Reference no. : RG35/22