TY - JOUR
T1 - Fundamental mode intensity evolution in tapered optical fibres
AU - Ek-Ek, J. R.
AU - Martinez-Pinon, F.
AU - Alvarez-Chavez, J. A.
AU - Ceballos-Herrera, D. E.
AU - Sanchez-Lara, R.
AU - Offerhaus, H. L.
N1 - Publisher Copyright:
© 2020 Astro Ltd.
PY - 2020/12/1
Y1 - 2020/12/1
N2 - The mode field intensity, spot size, central peak intensity evolution and adiabaticity are calculated for different points along the transition of an optical fibre taper that adiabatically tapers from the standard 125 nm down to 1 µm and then to 440 nm diameter for low loss operation at 1550 nm wavelength. The first section of the taper is evaluated using a weak guidance approximation. The second section is treated as a three-index layer structure (double-clad) and evaluated with eigenvalue equations for three refractive indices. The third and thinnest section of the taper is studied using an exact mode eigenvalue equation. The results show that the fundamental mode for the third section has a discontinuity at the fibre edge with a peak intensity larger than the intensity at the centre of the fibre. Since the guiding by the core disappears in the first section of the taper, the mode field does not simply reduce monotonously along the taper with the outer diameter of the fibre. By this novel approach, and for the first time, to the best of our knowledge, the taper shape that complies with the adiabaticity criterion, the mode intensity profile and the spot size (first Petermann definition) of the fundamental mode evolution, along their position on the taper are determined.
AB - The mode field intensity, spot size, central peak intensity evolution and adiabaticity are calculated for different points along the transition of an optical fibre taper that adiabatically tapers from the standard 125 nm down to 1 µm and then to 440 nm diameter for low loss operation at 1550 nm wavelength. The first section of the taper is evaluated using a weak guidance approximation. The second section is treated as a three-index layer structure (double-clad) and evaluated with eigenvalue equations for three refractive indices. The third and thinnest section of the taper is studied using an exact mode eigenvalue equation. The results show that the fundamental mode for the third section has a discontinuity at the fibre edge with a peak intensity larger than the intensity at the centre of the fibre. Since the guiding by the core disappears in the first section of the taper, the mode field does not simply reduce monotonously along the taper with the outer diameter of the fibre. By this novel approach, and for the first time, to the best of our knowledge, the taper shape that complies with the adiabaticity criterion, the mode intensity profile and the spot size (first Petermann definition) of the fundamental mode evolution, along their position on the taper are determined.
KW - Adiabaticity condition
KW - First peterman definition
KW - Fundamental mode evolution
KW - Optical fibres taper
KW - Spot size evolution
UR - http://www.scopus.com/inward/record.url?scp=85097224720&partnerID=8YFLogxK
U2 - 10.1088/1555-6611/abbe1e
DO - 10.1088/1555-6611/abbe1e
M3 - Artículo
AN - SCOPUS:85097224720
SN - 1054-660X
VL - 30
JO - Laser Physics
JF - Laser Physics
IS - 12
M1 - 126204
ER -