1、CEN PRENa2591-FL 93 m 3404589 004bb30 348 AECMA STANDARD NORME AECMA AECMA NORM prEN 2591-FI Edition P 1 June 1993 DIT PAR LASSOCIATION EUROPENNE DES CONSTRUCTEURS DE MATERIEL AEROSPATIAL Technopolis - 175, rue Jean-Jacques Rousseau - F-92138 Issy-les-Moulineaux Cedex - Tl. (1 1 47.36.98.76 UDC : De
2、scriptors : ENGLISH VERSION Aerospace series Elements of electrical and optical connection Test methods Part FI - Optical elements Insertion loss Srie arospatiale Luft- und Raumfahrt Mthodes dessais Prfverfahren Pertes dinsertion Einf gungsdmpfung Organes de connexion lectrique et optique Partie FI
3、- Organes optiques Elektrische und optische Verbindungselemente Teil FI - Optische Elemente This “Aerospace Series“ Prestandard has been drawn up under the responsibility of AECMA (Association Europenne des Constructeurs de Matriel Arospatial It is published on green paper for the needs of AECMA-Mem
4、bers. It has been technically approved by the experts of the concerned Technical Committee following comment by the Member countries. Subsequent to the publication of this prestandard, the technical content shall not be changed to an extent that interchangeability is affected, physically or function
5、ally, without re-identification of the standard. After examination and signature of the AECMA Standard Checking Centie INPSI and formal agreement of the Officiai Services of the Member countries it will be submitted as a draft European Standard to CEN (European Cornmittee for Standardization) for fo
6、rmal vote. Nota - Extra copies can be supplted by B.N.A.E. - Technopolis 54 - 199, rue Jean-Jacques Rousseau - 921 38 ISSY-LES-MOULINEAUX CEDEX I Edition approved for publication Comments should be sent within cix months after the date of publication to C2 Chairman I AECMA I Technooolis - 175. rue J
7、ean-Jacoues Rousseau 1993-06-30 I 921 38 Issy-les-Moulineaux CedLx . FRAKCE I Mr. Le Cunff aecma 1993 CEN PREN*259L-F1 93 m 3404589 004bb31 284 m prEN 259 method, number of measurements to be averaged, preconditioning requirements, recovery procedure, number of channels to be tested in a multi-chann
8、el device, maximum value of insertion loss, maximum permissible standard deviation of insertion loss, launch conditions. -FI Page 3 1 Scope This standard specifies methods of measuring the insertion loss of optical connection elements (including permanent connections) and fibre optic couplers. These
9、 methods are suitable for single and multi-channel devices and hybrid configurations. It shall be used together with EN 2591. 2 Normative references EN 2591 Aerospace series - Elements of electrical and optical connection - Test methods - General 3 Preparation of specimens 3.1 Specimens shall be pre
10、pared as defined in the product standard and for each method of test : - the fibre ends shall comply with requirements of EN 2591 (Fibre end preparation and termination cleaning), - the fibre ends shall be fixed to the light launch and detector systems as defined in EN 2591, - the fibrekable used fo
11、r the test shall meet the requirements of the optical connection element, coupler or splice product standard, - movement of the fibreskables and temporary joints shall be minimized during the test Set-up and testing process, - the minimum bend radius of the fibrekable shall not be exceeded - the fib
12、re lengths shall be as stated unless otherwise defined in subsequent test requirements. 3.2 Unless otherwise indicated in the technical specification, the following details shall be specified : Previous page is blank 1) At the date of publication of this standard, general aspects of elements of opti
13、cal connection are covered by a draft amendment which is in preparation to the European Standard EN 2591. CEN PREN*259L-FL 93 3i104589 004bb32 LLO prEN 2591-FI Page 4 4 Apparatus It shall comprise : - - a Light Launch System (LLS) as defined in EN 2591, a Light Detector System (LDS) as defined in EN
14、 2591. In addition, the following apparatus shall be required depending upon the method used : a) temporary joints (ti) 1) the joints shall have a low insertion loss, good performance repeatability and have minimum 2) the mean insertion loss and standard deviation of the joints shall be specified in
15、 the product 3) the standard deviation of any temporary joint shall be one order of magnitude better than that reflection loss. Index matching material may be used. standard. stated in the product standard for the device under test. b) reference specimen 1) the dimensions and parameters shall be spe
16、cified in the product standard. 2) the mean insertion loss shall be specified in the product standard. 3) the standard deviation of the insertion loss shall be specified in the product standard. 5 Methods A number of methods may be used to measure insertion loss. However, the principle is basically
17、the same for each method. First, the amount of useful optical power which can be transmitted through the cable shall be measured without the specimens installed. Then, the specimen shall be inserted into the cable and the amount of useful power shall be measured again. The insertion loss shall be de
18、fined as the decrease in the amount of transmitted optical power and shall be expressed as a ratio in decibels (dB). The launch conditions shall be defined in EN 2591. 5.1 Method 1 It shall be limited to a single measurement. It shall involve making the initial power measurement in a continuous (unb
19、roken and without temporary joints) fibre. The fibre shall then be broken, the specimen inserted and the power measured again. This method requires a new length of fibre as well as the preparation and interfacing of the fibre to the LLS and IDS for each specimen measured. a) Initial measurement Set-
20、up, see figure 1. L = (2f0,I) m Figure 1 CEN PREN*257L-F1 93 3404587 004bb33 057 W prEN 2591-FI Page 5 b) Measure power Po c) Cut fibre length L into two equal sections. The preparation of fibre ends shall comply with EN 2591. Install the specimen as shown in figure 2. Specimen ILLSI _ n _ pi Figure
21、 2 d) Measure power Pi. e) Calculate the insertion loss using the following equation Pi Insertion loss (dB) = -10 log - Po 5.2 Method 2 This method shall apply to pig-tailed arrangements. It shall use two temporary joints. NOTE : The results will depend on the quality of the two joints and fibres. I
22、n some situations, a negative value of insertion loss may be measured. a) Initial measurement Set-up, see figure 3. LI and L3 shall not exceed 5 m L2 = (2 f 0,l) m Figure 3 b) Measure power Po c) Remove fibre L2 and replace it with the pig-tailed specimen as shown in figure 4. Figure 4 d) Measure po
23、wer Pi e) Calculate the specimen insertion loss using the following equation : Pi Insertion loss (dB) = -10 log - Po NOTE : Half of the temporary joint can be an optical face on the LLS or LDS, which means LI and L3 can be zero. prEN 2591-FI Page 6 5.3 Method 3 This method is intended to minimize th
24、e ambiguities created by fibre parameter mismatches. It shall be limited to measuring pig-tailed arrangements and involve the use of temporary joints. Although it incorporates a temporary joint, the measurement shall not be dependent on the reproducibility of the joint. a) Initial measurement Set-up
25、, see figure 5. 1 = L2 = (1 10,l) m L355m Figure 5 b) Measure power Pi. c) Cut the fibre between the temporary joint and the specimen at location L1 as shown in figure 6. L1 = (0,5 f 0,l) m Figure 6 d) Remove the specimen and its attached fibres from the test circuit. e) Prepare the fibre end of L1
26、as defined in EN 2591. Couple it to the LDS as shown in figure 7. f) Measur Figure 7 power Po g) Calculate the specimen insertion loss using the following equation : Pi Insertion loss (dB) = -10 log - Po 5.4 Method 4 This method shall apply to specimens with integral cable terminations (patch cord)
27、and uses a reference specimen. a) Initial measurement Set-up, see figure 8. L1 = L2 = (1 rt0,I) m Figure 8 CEN PREN*25L-Fl 93 m 3404587 0046635 72T m prEN 2591-FI Page 7 I b) Measure power Po. I c) Disconnect the reference specimen and insert the test specimen as shown in figure 9. L352m Figure 9 d)
28、 Measure power Pi. e) Calculate the insertion loss using the following equation : Pi Insertion loss (dB) = -10 log - Po 5.5 Method 5 This method shall be limited to evaluating a connector set adaptor. It shall involve the use of two Reference connector Plugs RP and Reference Adaptor RA of known perf
29、ormance. a) Initial measurement Set-up, see figure 1 O. LI = L225r-n Figure 10 b) Measure power Po. c) Remove RA and replace it with the Adaptor A to be measured as shown in figure 11. d) Measure power Pi. Adaptor gmpj Figure 11 e) Calculate the insertion loss of A using the following equation : Pi
30、Insertion loss (dB) = -10 log - Po NOTE : In this method, the resultant value shall be the additional loss that the adaptor under test produces, compared to that associated with the reference adaptor, in power level (Po). This method may yield loss values that are negative (apparent gain for the ada
31、ptor) and care shall be used in interpreting the results. CEN PREN*2591-F1 93 = 3404587 004bb3b 8bb = -FI Page 8 prEN 259 5.6 Statistical assessment of insertion loss - Connectors A more valid assessment of the performance can be achieved by calculating the mean and standard deviation of a number of
32、 measurements. The number of measurements and the method for remating the connector when making multiple measurements depends on the nature of the particular connector family and arrangement. The following procedure for remating shall be followed : a) The connector set shall be completely uncoupled
33、and recoupled for each measurement. b) Non-keyed connector sets shall be relatively rotated 1 20 between components and multiple measurements made at each location. c) Single keyed connectors shall have multiple measurements made at the keyed position. d) Multi-keyed connectors shall have multiple m
34、easurements made at each keyed position. e) Patch cord connectors : in combination with the above rotations, reverse the orientation of the patch cord with respect to the direction of propagation of the light and the fixed plugs and adaptors. The number of measurements to be made relative to the above positions shall be specified in the product standard. 5.7 Requirements Insertion loss and standard deviation shall not exceed values specified in the product standard.
