IEC 61300 2 43 Edition 2 0 2014 06 INTERNATIONAL STANDARD NORME INTERNATIONALE Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 2 43 Tests – Sc[.]
Selection of the reflection standard cord
The reflection standard plug (RP) shall be selected by the following procedure a) Set up an objective reflection standard cord as shown in Figure 1
The measurement setup for the open plug reflection standard is illustrated in Figure 1 The detector is calibrated to 14.7 dB, corresponding to the Fresnel reflection occurring at the interface between air and the silica fiber core The refractive index of air is 1.0, while that of the silica fiber is significantly different.
1,452 for single-mode fibre on condition ∆ = 0,3 %, λ = 1,31 àm
To enhance measurement accuracy, it is essential to utilize the actual parameters of the employed fibers Additionally, connect another objective reflection standard cord as illustrated in Figure 2, and proceed to measure the return loss.
The measurement setup for mated reflection standard cords involves using a pair of objective reflection standard cords, ensuring that their return loss from the mating point is defined as \(L_{rs} + \beta\) (in decibels) Here, \(L_{rs}\) represents the designed minimum return loss, and the value of \(\beta\) must be set to exceed 2 dB.
Cord screen testing
a) Connect the device under test (DUT) (cord) between the reflection standard plugs as shown in Figure 3
The measurement setup for cord screen testing involves measuring the return loss \( L_r \) in decibels from the two PC mating points The objective cord is classified as a screen tested cord when \( L_r \) exceeds \( L_{rs} \).
Pigtail cord screen testing
a) Connect the objective PC connector of DUT (pigtail cord) to one reflection standard plug as shown in Figure 4, and terminate pigtail fibre end
The measurement setup for pigtail cord screen testing involves measuring the return loss \( L_r \) in decibels from the mating point A pigtail cord is considered screen tested when \( L_r \) exceeds \( L_{rs} + \alpha \) in decibels, with \( \alpha \) set between 0.6 dB and 5 dB.
The following details, as applicable, shall be specified in the relevant specification:
– minimum return loss L rs (in decibels);
– condition of standard reflection plugs (the value of β in decibels);
– screening condition for pigtail cords (the value of α in decibels);
– attenuation of mating points between the reflection standard connectors and the objective connectors;
Screen testing of return loss of pigtails having PC fibre optic connector
This annex outlines the theoretical framework for screen testing return loss in pigtails, mirroring the process used for cords with PC fibre optic connectors The method involves selecting a pair of reference connectors and conducting a screen test on a measurement pigtail using these reference connectors This testing is performed under conditions established through simulation, taking into account the distribution of the high refractive index layer resulting from the polishing process.
This method introduces two key parameters, β and α Parameter β is utilized for selecting a pair of reference connectors, while parameter α serves as a criterion for screen testing measurement connectors Both parameters are meticulously determined through simulation to ensure that the return loss at the mating point surpasses a specified return loss, L rs, with a high probability when the screen-tested connectors are randomly connected.
– refractive index of fibre core n 1 is 1,452;
– refractive index of air n 2 is 1,0
The measurement and test procedures are initiated with the set-up illustrated in Figure A.1, which includes reference cords 1 and 2, with connectors 1a and 2a serving as reference points Connectors 3a and 3b are designated for the cord under test, while 4a is for the pigtail under examination Angled connectors with high return loss are represented by 1b, 2b, and 5b The optical source is denoted as S, the optical detector as D, and the optical coupler as BD Additionally, T represents a fibre termination that must exhibit a high return loss, achieved through the use of index matching material at the fibre end or by applying high attenuation techniques, such as a mandrel wrap.
Figure A.1 – Measurement set-up of the screen test method
P0 is the input power and P8, P1, P2 and P3 are the reflected powers The symbols , , ,
The procedure of the screen test method is as follows: a) A pair of reference plugs is selected
– Connect the connector 1b to the connector 5b, then measure the power P8 (see in
– Connect the reference connector 2a to the reference connector 1a, then measure the power P1 (see in Figure A.1)
The condition of selection is given by:
L rs < –10 log P1/P0 ≤ L rs + β (dB) (A.1) The measured power P0 can be described using P8, n 1 and n 2 as follows:
The second term of the right side represents Fresnel reflection of air, and equals 14,7 dB
Therefore Equation (A.1) can be rewritten as:
0 < –10 log P1/P8 + 14,7 – L rs ≤ β (A.3) b) The cord under test is screen tested using the pair of reference connectors
– Connect the cord under test 3 between the reference connectors 1a and 2a, then measure the power P2 (see in Figure A.1)
Reference cord 1 Adapter Reference cord 2 1b 1a
The criteria for the screen test of the measurement connectors are given by:
–10 log P2/P8 + 14,7 ≥ L rs + α (dB) (A.4) c) The pigtail under test is screen tested using one of the pair reference connectors
– Remove the reference connector 2a from reference connector 1a
– Connect measurement connector 4a to the reference connector 1a, then measure the power P3 (see in Figure A.1)
The criteria for the screen test of the measurement connectors is given by:
The parameters β and α are established through simulation to ensure that the return loss at the mating point significantly exceeds the specified return loss L rs with a high probability when the tested connectors are connected randomly.
Figure A.2 illustrates the relationship between β and α, established by the requirement that the return loss at the mating point surpasses a specified value L rs with a 99% probability The simulation results for pigtails are represented by white circles, while black circles denote the results for cords, with the lines indicating first-order regression The data reveals that the return loss of randomly concatenated cords exceeds L rs (in decibels) with a 99% probability when α is greater than or equal to 0.4β – 2.0 Consequently, the parameters β and α must be determined based on this condition.
Figure A.3 illustrates the cumulative probability of return loss prior to screen testing, while Figure A.4 depicts the cumulative probability of return loss for pigtails that underwent screen testing, adhering to the conditions outlined in Equation (A.5) with the reference cord chosen as per the specifications of the equation.
(A.1) The parameters L rs , β and α are set at 45 dB, 5 dB and 2 dB, respectively For pigtails, the probability exceeds 99 % when the return loss L rs is greater than 45 dB
Figure A.3 – Cumulative probability of return loss before test
Figure A.4 – Cumulative probability of return loss after test
For effective screen testing of pigtails, it is crucial that the fiber surface condition of one reference connector closely matches that of the paired reference connector.
Figure A.5 illustrates the relationship between the differences in P4 and P5, as well as the differences in α a and α b P4 and P5 represent the reflected power of the paired reference connectors, with power measurements conducted as outlined in Figure A.6, where the symbols maintain consistent meanings.
The parameters \( \alpha_a \) and \( \alpha_b \) represent individual criteria indicating that the return loss of randomly concatenated connectors, chosen based on the individual reference connector, surpasses a specified value \( L_{rs} \) with a 99% probability under certain conditions.
–10 log P2/P8 + 14,7 ≥ L rs + α a (dB); or –10 log P2/P8 + 14,7 ≥ L rs + α b (dB)
Figure A.5 shows that the fibre surface condition of the reference connector 1a is almost equal to that of the reference connector 2a when the difference between the measured power
P4 and P5 is small The power P4 and P5 shall satisfy the following condition to obtain the small difference between α a and α b within 1,0 dB:
C um ul at iv e pr ob abi lit y (% )
C um ul at iv e pr ob abi lit y ( % )
Figure A.5 – Relationship between power and α
Figure A.6 – Measurement set-up of the reflected powers
IEC 61300-1, Fibre optic interconnecting devices and passive components – Basic test and measurement procedures – Part 1: General and guidance
5.1 Choix du cordon de réflexion de référence 18
5.2 Essai de sélection des connecteurs montés sur cordons 18
5.3 Méthode de sélection des connecteurs à fibres amorces 19
Annexe A (informative) Sélection en fonction de l’affaiblissement de réflexion des fibres amorces optiques ayant des connecteurs PC pour fibres 20
Figure 1 – Montage de mesure pour fiche de réflexion de référence en position ouverte 18
Figure 2 – Montage de mesure pour cordons de réflexion de référence accouplés 18
Figure 3 – Montage de mesure pour essai de sélection des connecteurs montés sur cordons 19
Figure 4 – Montage de mesure pour essai de sélection des connecteurs à fibres amorces 19
Figure A.1 – Montage de mesure de la méthode d'essai de sélection 21
Figure A.3 – Probabilité cumulative de l’affaiblissement de réflexion avant essai 23
Figure A.4 – Probabilité cumulative de l’affaiblissement de réflexion après essai 23
Figure A.5 – Relation entre puissance et α 24
Figure A.6 – Montage de mesure des puissances réfléchies 24
DISPOSITIFS D’INTERCONNEXION ET COMPOSANTS PASSIFS À FIBRES OPTIQUES – PROCÉDURES FONDAMENTALES D’ESSAIS ET DE MESURES –
Partie 2-43: Essais – Sélection des connecteurs PC pour fibres optiques unimodales en fonction de leur affaiblissement de réflexion
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Choix du cordon de réflexion de référence
La fiche de réflexion de référence (RP) doit être choisie par la procédure suivante a) Disposer un cordon de réflexion de référence objectif comme représenté à la Figure 1
Figure 1 illustrates the measurement setup for the reference reflection sheet in the open position Adjust the detector to 14.7 dB, capturing the Fresnel reflection between air and the silica core of the fiber, as shown in the figure The refractive index of air is 1.0, while the refractive index of the silica fiber is 1.452 for single-mode fibers, under the condition of ∆ = 0.3% and a wavelength of λ = 1.31 µm.
The accuracy of the measurement can be enhanced by considering the actual parameters of the fibers used Additionally, it is important to connect another reference reflection cord as illustrated.
Figure 2, et mesurer ensuite l’affaiblissement de réflexion;
Figure 2 illustrates the measurement setup for coupled reference reflection cords To use the objective pair of reference reflection cords, their reflection loss from the coupling point must be L rs + β (in decibels), where L rs represents a predefined minimum reflection loss Additionally, the value of β should be adjusted to exceed 2 dB.
Essai de sélection des connecteurs montés sur cordons
a) Raccorder le dispositif en essai (DUT) (cordon) entre les fiches de réflexion de référence comme représenté à la Figure 3
Figure 3 illustrates the measurement setup for testing the selection of connectors mounted on cords The reflection loss, denoted as L_r (in decibels), is measured from the two coupling points PC A cord is deemed selected when the reflection loss L_r exceeds the threshold L_rs.
Méthode de sélection des connecteurs à fibres amorces
a) Raccorder le connecteur PC objectif du DUT (cordon à fibre amorce) à une fiche de réflexion de référence comme indiqué à la Figure 4, et raccorder l'extrémité à fibre amorce
The measurement setup for testing the selection of fiber optic connectors involves measuring the reflection loss \( L_r \) in decibels from the coupling point A fiber optic pigtail is considered selected when \( L_r \) exceeds \( L_{rs} + \alpha \) in decibels, where the adjustment of the value of \( \alpha \) should be within a specified range.
Les détails suivants doivent, le cas échéant, être stipulés dans la spécification applicable:
– affaiblissement de réflexion minimal L rs (en décibels);
– condition des fiches de réflexion de référence (valeur de β en décibels);
– condition de sélection pour cordons à fibre amorce (valeur de α en décibels);
– affaiblissement des points d'accouplement entre les connecteurs de réflexion de référence et les connecteurs objectifs;
Sélection en fonction de l’affaiblissement de réflexion des fibres amorces optiques ayant des connecteurs PC pour fibres
This annex outlines the theoretical foundation for selecting launch fibers based on reflection loss The initial concept mirrors that of selection tests for optical fibers with PC connectors: a reference connector pair is chosen, and the measurement launch fiber undergoes a selection test using the reference connector under specific conditions determined by a simulation This simulation accounts for the distribution of the high-refractive-index layer created during the polishing process.
This method introduces two parameters, β and α The parameter β is used to select a pair of reference connectors, while parameter α serves as a criterion for testing the selection of measurement connectors Both parameters are carefully determined through simulation to ensure that the reflection loss at the coupling point exceeds a specified reflection loss, L rs, with a high probability when the connectors undergoing selection tests are connected randomly.
Cette méthode part des hypothèses suivantes:
– l'indice de réfraction du cœur de la fibre n1 est 1,452;
– l'indice de réfraction de l'air n 2 est 1,0
Le montage de mesure et les procédures d'essai seront représentés en premier lieu La
Figure A.1 illustrates the setup featuring reference cords 1 and 2, with 1a and 2a representing the reference connectors Points 3a and 3b correspond to the connectors of the test cord, while 4a is the connector of the test launch fiber Connectors 1b, 2b, and 5b are angled connectors that exhibit high reflection loss S denotes the optical source, D is the optical detector, and BD represents the optical coupler T is a fiber termination that must have high reflection loss; to achieve this, it is advisable to apply an index-matching adhesive at the fiber's end or introduce high loss in the fiber, for instance, by winding it on a mandrel.
Figure A.1 – Montage de mesure de la méthode d'essai de sélection
P0 est la puissance d'entrée et P8, P1, P2 et P3 correspondent aux puissances réfléchies
Les symboles , , , indiquent les conditions de connexion
La procédure pour la méthode d'essai de sélection est la suivante: a) On choisit une paire de fiches de référence
– Connecter le connecteur 1b au connecteur 5b, mesurer ensuite la puissance P8
– Connecter le connecteur de référence 2a au connecteur de référence 1a, ensuite mesurer la puissance P1 (voir à la Figure A.1)
La condition du choix est donnée par:
La puissance mesurée P0 peut être décrite en utilisant P8, n 1 et n 2 comme suit:
Le second terme de la partie droite représente la réflexion de Fresnel de l'air et elle est égale à 14,7 dB C'est pourquoi l'Equation (A.1) peut être réécrite comme suit:
0 < –10 log P1/P8 + 14,7 – L rs ≤ β (A.3) b) Le cordon en essai est soumis à l'essai de sélection en utilisant la paire de connecteurs de référence
– Connecter le cordon en essai 3 entre les connecteurs de référence 1a et 2a, puis mesurer la puissance P2 (voir à la Figure A.1)
Cordon de référence 1 Raccord Cordon de référence 2 1b 1a
Raccord Fibre-amorce en essai
Les critères pour l'essai de sélection des connecteurs de mesure sont donnés par:
–10 log P2/P8 + 14,7 ≥ L rs + α (dB) (A.4) c) La fibre amorce en essai est soumise à l'essai de sélection en utilisant une des paires de connecteurs de référence
– Enlever le connecteur de référence 2a du connecteur de référence 1a
– Connecter le connecteur de mesure 4a au connecteur de référence 1a, mesurer ensuite la puissance P3 (voir à la Figure A.1)
Les critères pour l'essai de sélection des connecteurs de mesure sont donnés par:
The parameters β and α are determined through simulation to ensure that the coupling point's reflection loss exceeds the specified reflection loss L rs with a high probability when the tested connectors are randomly connected.
Figure A.2 illustrates the relationship between β and α, derived from the condition that the reflection loss at the coupling point exceeds a specified value L rs with a 99% probability The white circles represent simulation results for the fiber pigtails, while the black circles denote those for the cords The lines indicate first-order regression lines The figure demonstrates that the reflection loss of randomly concatenated cords exceeds L rs (in decibels) with a high probability.
99 % avec la condition de α ≥ 0,4β – 2,0 Les paramètres β et α doivent être déterminés en fonction de cette condition
Figure A.3 illustrates the cumulative probability of reflection weakening prior to selection tests In contrast, Figure A.4 depicts the cumulative probability of reflection weakening after the fibers have undergone a selection test, as defined by Equation (A.5), utilizing the reference cord selected according to Equation (A.1) The parameters L rs, β, and α are set to specific values.
45 dB, 5 dB et 2 dB, respectivement Pour les fibres amorces, la probabilité dépasse 99 % si l'affaiblissement de réflexion L rs est plus supérieur à 45 dB
Figure A.3 – Probabilité cumulative de l’affaiblissement de réflexion avant essai
Figure A.4 – Probabilité cumulative de l’affaiblissement de réflexion après essai
For the fiber selection test, it is crucial that the surface condition of one reference connector in the pair closely matches that of the other reference connector Figure A.5 illustrates the relationship between the difference in P4 and the relevant parameters.
P5 and the difference between α a and α b represent the reflected powers of the reference connectors in pairs These powers are measured as illustrated in Figure A.6, where the symbols have the same meaning as in Figure A.1 The parameters α a and α b serve as individual criteria, indicating that the reflection loss of randomly selected concatenated connectors using the individual reference connector exceeds a specified value L rs with a probability of 99% under the given conditions.
–10 log P2/P8 + 14,7 ≥ L rs + α a (dB); ou –10 log P2/P8 + 14,7 ≥ L rs + α b (dB)
Figure A.5 illustrates that the surface condition of the fibers in reference connector 1a closely resembles that of reference connector 2a when the difference between the measured powers P4 and P5 is minimal To achieve a small difference of approximately 1.0 dB between α a and α b, the powers P4 and P5 must meet the following condition.
P rob abi lit é cum ul at iv e ( % )
P rob abi lit é cum ul at iv e ( % )
Figure A.5 – Relation entre puissance et α
Figure A.6 – Montage de mesure des puissances réfléchies
Raccord Fibre-amorce en essai
IEC 61300-1, Dispositifs d'interconnexion et composants passifs à fibres optiques –
Procédures fondamentales d'essais et de mesures – Partie1: Généralités et lignes directrices