Transmission properties of tapered optical fibres: Simulations and experimental measurements

Incoherent Light in Tapered Graded-Index Fibre: A Study of Transmission and Modal Noise

“…The experimental results, however do not agree with the COMSOL calculations as much lower transmission than GI tapers was seen. This is consistent with previous work [3]. The higher losses in the step index tapers is probably due to the destruction of the core/cladding interface during the tapering process for these fibres.…”

“…Hence, when GI fibre is tapered, the drop of transmission is seen at 𝑁𝐴 ef f > 𝑁𝐴 taper . This was also seen in COMSOL simulations which used EM waveguide calculations that are presented in [3]. In addition, the overall transmission of incoherent light for both untapered and tapered fibre is less than the coherent light results.…”

“…Tapered fibres are known to be compact and effective beam converters [1,2]. When used in fibre-fed spectrographs, they present a low-loss and compact alternative to other converters [2,3]. It is possible to heat and permanently stretch any fibre to narrow it down over a defined short length; thus, single mode (SM) fibres or multimode (MM) fibres can be tapered to meet the needs of a given application.…”

“…Our previous work examined the transmission of tapered gradedindex fibres as a function of effective numerical aperture (𝑁𝐴 ef f ) for monochromatic light [3]. Here, we expand this study by using a broadband (400-600 nm) incoherent illumination source, a Tungsten Halogen lamp.…”

“…Coherent light transmission results [3] indicate that graded-index tapered fibre is an effective candidate for transferring light into a spectrograph instead of using more complicated fabrication processes for example Photonic Lanterns [4,5] or multicore fibre [15]. Incoherent light testing was not performed in the taper investigations of the previous work.…”