TY - JOUR
T1 - Incoherent light in tapered graded-index fibre: a study of transmission and modal noise
AU - Choochalerm, Piyamas
AU - Martin, Bill
AU - Jones, Hugh
AU - Usher, Sarah
AU - Wright, Thomas
AU - Yerolatsitis, Stephanos
N1 - © 2022 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license, http://creativecommons.org/licenses/by/4.0/
PY - 2023/1/30
Y1 - 2023/1/30
N2 - We investigated the impact of taper length on light transmission through tapered graded-index fibres. We tested commercial fibres from Thorlabs and a custom graded-index fibre using both coherent and incoherent light sources. Our experimental results show optimum performance for taper transition lengths of 25 mm, although our simulations suggest further improvement may be possible for even shorter transition lengths. We also measured the modal noise power fluctuations caused by bending the fibre. Here, we observe that the custom fibre tapers have the highest transmission but suffer from the most modal noise. Accordingly, we find that the commercial graded-index fibre tapers promise practical usage as a beam mode-field converter, as they have lower power fluctuations but retain relatively high transmission if compared to commercial small core step-index fibre.
AB - We investigated the impact of taper length on light transmission through tapered graded-index fibres. We tested commercial fibres from Thorlabs and a custom graded-index fibre using both coherent and incoherent light sources. Our experimental results show optimum performance for taper transition lengths of 25 mm, although our simulations suggest further improvement may be possible for even shorter transition lengths. We also measured the modal noise power fluctuations caused by bending the fibre. Here, we observe that the custom fibre tapers have the highest transmission but suffer from the most modal noise. Accordingly, we find that the commercial graded-index fibre tapers promise practical usage as a beam mode-field converter, as they have lower power fluctuations but retain relatively high transmission if compared to commercial small core step-index fibre.
KW - Adiabatic tapered fibre
KW - Fibre transmission
KW - Graded-index fibre
KW - High-resolution spectrograph
KW - Incoherent light source
KW - Modal noise
KW - Numerical aperture characterisation
UR - http://www.scopus.com/inward/record.url?scp=85145595156&partnerID=8YFLogxK
U2 - 10.1016/j.yofte.2022.103140
DO - 10.1016/j.yofte.2022.103140
M3 - Article
AN - SCOPUS:85145595156
SN - 1068-5200
VL - 75
SP - 1
EP - 9
JO - Optical Fiber Technology
JF - Optical Fiber Technology
M1 - 103140
ER -