1、BRITISH STANDARD Fibre optic interconnecting devices and passive components - Basic test and measurement procedures Part 3. Examinations and measurements Section 19. Polarization dependence of return loss of a single-mode fibre optic component The European Standard EN 61300519 : 1997 has the status
2、of a British Standard ICs 33.180.20 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BS EN 1997 1997 31300-3-19 : EC 61300-3-19 : BS EN 613003-19 : 1997 This British Standard, having been prepared under the direction of the Electrotechnical Sector Board, was published under the
3、 authority of the Standards Board and comes into effect on 15 July 1997 O BSI 1997 ISBN O 680 27703 8 National foreword This British Stan- is the English language version of EN 6130W19 : 1997. It is identical with IEC 61300-3-19 : 1997. The UK participation in its preparation was entsusted by Techni
4、cal Committee EPLM, Fibre optics, to Subcommittee EPU6/2, Interconnecting devices and passive components, which has the responsibility to: - aid enquirers to understand the text, - present to the responsible internationalEuropean commit - the application of an index match material to the fibre end;
5、- attenuation in the fibre, for example with a mandrel wrap. 3.9 Data read-out/recording/processing devices This device provides a means to collect the transmitted power as the SOP is scanned, to perform the calculations, and to report the results at the end of the test. A computer-based system may
6、be used to fulfil this data acquisition and analysis function. 4 Procedure 4.1 Precautions 4:l.l of the requirements specified in 3.1 to 3.9 and in the detail specification. The apparatus and arrangement necessary to make these measurements shall meet all 4.1.2 Since the characteristics of the PA, B
7、D, DUT, and D are all functions of the wavelength of the source, the wavelength and other characteristics of the source are important and shall be ensured. STD-BSI BS EN b1300-3-L7-ENGL 1777 Lb24bb7 b25b87 780 Page 8 EN 61300-3-19 : 1997 4.1.3 The terminator is important for the measurement. Procedu
8、res to reduce the reflected power from the detectors and temporary joints to an acceptable level shall be used as described in 3.8. 4.1.4 Movement of any of the fibres or apparatus during the measurement may affect the state of polarization and lead to measurement error. Therefore, care should be ta
9、ken to ensure that no movement of the fibres or apparatus is allowed. 4.1.5 Cladding modes shall be stripped at the entry and exit ports of each element of the apparatus. If this is not accomplished by the fibre coating, cladding mode strippers are required. See also notes 1 and 2 of 4.3.9. 4.2 Meth
10、od A - All states of polarization 4.2.1 Measure the transfer coefficients T23 (from port 2 to part 3), 12, Ti4 of the branching device (refer to annex A of IEC 875-1) to make sure that the BD meets the requirements specified in 3.4 (see figure 3). The source for these measurements shall be the same
11、as that used in measuring the polarization dependence of the return loss of the DUT. IEC 274197 Figure 3 - 2 x 2 polarization independent branching device (BD) 4.2.2 Configure the measurement set-up as shown in figure 4 with the elements specified in 3.1 to 3.9. The structure of PA is shown in figur
12、e 1. The precautions described in 4.1 shall be followed in configurng the test set-up and in performing the measurements. Figure 4 - Measurement set-up 4.2.3 After ensuring the stability of the test Set-up, maximize the detected signal Pl, by rotating the linear polarizer. Fix the rotation angle of
13、the P plate. 4.2.4 Rotate the quarter-wave plate Q by 10“ or some other incremental angle specified in the detail specification through 180“ while measuring P2 versus 6 and 9, the angular orientations of Q and H respectively. 4.2.5 detail specification. Rotate the half-wave plate H by 10“ or some ot
14、her incremental angle specified in the 4.2.6 Repeat steps 4.2.4 and 4.2.5 until the half-wave plate has been rotated through 180“. 4.2.7 Read and record the detected values of P2 and Pl at the same values of and q. 4.2.8 Without adjusting or disturbing the test arrangement, cut the fibre at TJ3 and
15、remove the DUT from the test. 4.2.9 Insert the reference fibre as shown in figure 5. Read and record the detected power P2 for each value of 0 and cp. Figure 5 - Measurement set-up 4.2.10 The polarization dependence of return loss is calculated as follows: 4.3 Method B - Linear polarization only 4.3
16、.1 Repeat step 4.2.1. 4.3.2 Configure the measurement set-up as shown in figure 4 with the elements specified in 3.1 to 3.9. The structure of PA is shown in figure 2. The precautions described in 4.1 shall be followed in configuring the test set-up and in performing the measurements. All of the laun
17、ch fibre shall be deployed in a straight line configuration. The length of fibre between the launch and the DUT shall be less than 1/8 of a fibre beat length to ensure the linear polarization state is maintained at the DUT. If this is not known, the length shall be less than 3 m. 4.3.3 rotating the
18、linear polarizer. Fix the rotation angle of the P plate. After ensuring the stability of the test set-up, maximize the detected signal, Pl, by 4.3.4 The detected power, P2(cp), is recorded as the linear state of polarization is rotated through 180, where cp is the angular orientation of the state of
19、 polarization. The incremental angular adjustment shall be chosen to ensure that the required accuracy for the determination of the maximum and minimum transmitted power is achieved. 4.3.5 The input fibre shall not be disturbed for the duration of the measurement procedure to ensure that the state o
20、f polarization launched into the DUT is not altered. 4.3.6 Without adjusting or disturbing the test arrangement, cut the fibre at TJ3 and remove the DUT from the test. 4.3.7 Insert the reference fibre as shown in figure 5. Read and record the detected power P2() and Pl). 4.3.8 minimum values of the
21、ratio are each determined with P2 and P1 at the same values of ip. Record the maximum and minimum values of the ratio P2/P1. These maximum and Page 10 EN 61300-3-19 : 1997 4.3.9 The polarization dependence of return loss is calculated as follows: NOTES 1 power PD, that is launched into the DUT. The
22、formula is effective provided that the splitting ratio of ED T,2 is equal to i,., .e power P, equals the PD = (TldT12)Pl. 2 of the DUT. It is assumed that the return loss of the test Set-up is polarization independent and is much higher than that 5 Details to be specified The following details, as a
23、pplicable, shall be specified in the detail specification: - Source peak wavelength and spectral width - Method to be used - Description of polarization adjuster - Incremental adjustment angle of the half-wave plate - Description of polarization independent branching device used - Description of the
24、 reference fibre - Pigtail lengths - Performance requirements - Any deviations from the test procedure. Page 11 EN 61300-3-19 : 1997 Annex ZA (normative) Normative references to international publications with their corresponding European publications This European Standard incorporates by dated or
25、undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only w
26、hen incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies (including amendments). NOTE: When an international publication has been modified by common modifications, indicated by (mod), the relevant ENIHD applies. Publication - Y
27、ear Title EN/HD - Year IEC 875-1 1996 Fibre optic branching devices Part 1 : Generic specification BS EN 61300-3-19 : I 1997 IEC 61300-3-19 : I BSI - British Standards Institution BSI 389 Chiswick High Road London w4 4AL ;SI is the independent national body responsible for preparing British Standard
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