| Standardization field | Electrical engineering
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| Technical committee | BAS/TC 30- Electric cables |
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| Term (EN) | bound mode |
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| Definition (EN) | In an optical fibre, a mode whose field decays monotonically in the transverse direction everywhere external to the core and which does not lose power to radiation.
Notes.
1 — Where the refractive index decreases with distance from the axis and where there is no central refractive index dip a bound mode is one for which :
n(a)k ≤ β ≤ n(0)k
where β is the imaginary part (phase coefficient) of the axial propagation coefficient,
n(a) is the refractive index at r = a, the radius,
n(0) is the refractive index at r = 0,
k is the angular free space wavenumber 2 π/λ and λ is the wavelength.
2 — Bound modes correspond to guided light rays in the terminology of geometric optics.
3 — In a multimode fibre, the power in bound modes is predominantly contained in the core of the fibre. |
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| Term (FR) | |
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| Definition (FR) | |
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| Term (DE) | |
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| Definition (DE) | |
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| Term (BS) | |
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| Definition (BS) | |
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| Term (HR) | |
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| Definition (HR) | |
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| Term (SR) | granični mod |
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| Definition (SR) | U optičkom vlaknu, režim rada kod koga polje opada monotono u poprečnom pravcu svuda van jezgre i koje ne gubi snagu zračenja.
Napomene
1 – Gdje indeks prelamanja opada sa udaljavanjem od ose i gdje ne postoji centralni propad indeksa prelamanja, granični mod je jedan za koji važi:
n(a)k ≤ β ≤ n(0)k
gdje je β imaginarni dio (fazni koeficijent) koeficijenta aksijalnog prostiranja,
n(a) je indeks prelamanja za r=a radijus,
n(0) je indeks prelamanja za r=0;
k je ugaoni talasni broj slobodnog prostora 2 π/λ i λ talasna dužina.
2 – Granični modovi odgovaraju vođenim svjetlosnim zrakama u terminologiji geometrijske optike.
3 – Kod multimodnog vlakna, snaga kod graničnih modova je dominantno sadržana u jezgri vlakna. |
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| Date | 2017-08-09 |
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| Standards | BAS IEC 60050-731:2017 |
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