1、ANSI/TIA/EIA-455-107A-I999 Approved: February 8, 1999 TIAEIA STANDARD FOTP-107 Determination of Component Reflectance or LinWSystem Return Loss Using a Loss Test Set (Revision of EIATIA-455-107) MARCH 1999 TELECOMMUNICATIONS INDUSTRY ASSOCIATION Elsctrarn ir Industries Allia RCC Copyright Telecommun
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6、on. This Standard does not purport to address all safety problems associated with its use or all applicable regulatory requirements. It is the responsibility of the user of this Standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations
7、 before its use. (From Standards Proposal No. 2961-A, formulated under the cognizance of the TIA FO-6.3 Subcommittee on Fiber Optic Interconnecting Devices). Published by OTELECOMMUNICATIONS INDUSTRY ASSOCIATION 1999 Standards and Technology Department 2500 Wilson Boulevard Arlington, VA 22201 PRICE
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9、der license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TINEIA 455-1 07A FOTP-107 Determination of component reflectance or lin Wsystem return loss using a loss test set Contents . Foreword III Introduction . 1 Normative references 2 Apparat us . 3 Samp
10、ling and specimens 5 Procedure . 5 Calculation or interpretation of results 9 Documentation 9 Specification information . 10 Annex A (informative) 11 Annex B (informative) 16 Annex C (informative) 19 Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for Resa
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12、 FOTP-107 Determination of component reflectance or lin idsystem return loss using a loss test set Foreword (This Foreword is informative only and not part of this Standard.) This document comes from TIA Standards Proposal No. 2961, formulated under the cognizance of TIA FO-6.3, Subcommittee on Fibe
13、r Optic Interconnecting Devices. This FOTP is part of the series of test procedures included within Recommended Standard EIMIA-455. NOTE: This FOTP was previously published in EIMIA-455-1 07 as FOTP-I 07. There are two informative annexes. iii Copyright Telecommunications Industry Association Provid
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15、ithout license from IHS-,-,-TINEIA 455-1 07A FOTP-107 Determination of component reflectance or lin idsystem return loss using a loss test set 1 I nt rod uction 1.1 Intent This procedure is used to determine the ratio in decibels of the power reflected by the port of a component or assembly to the i
16、ncident power on the same port of that component or assembly when that component or assembly is introduced into a link or system. This ratio is termed “Return Loss“ when applied to a fiber optic system or link. Return loss, by convention, is a positive number. The ratio of reflected to incident powe
17、r is termed “Reflectance“ when applied to an individual component. Reflectance, by convention, is a negative number. 1.2 Scope This test procedure provides only a cumulative return loss for systems or links being tested. This procedure also provides a reflectance measurement for discrete components.
18、 If the reflectance for individual components in series within a system must be analyzed, FOTP-8 should be used in lieu of this procedure. This procedure offers two methods for measuring reflected power using a branching device and loss test set(s). These test methods may be destructive in nature an
19、d therefore not desirable for production testing. Annex A offers specialized variations of the test methods, for use in the non-destructive testing of connectorized assemblies. 1.3 Background It has been determined that returned power such as that caused by Fresnel reflections, when introduced to an
20、 optical system, can cause degradation to the transmitted signal or to the system light source or to both. Studies have indicated a need for a minimum specified return loss within optical systems based upon their transmission characteristics. This FOTP has been developed to provide a means of measur
21、ing return loss and reflectance. 1 Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TINEIA 455-1 07A 1.4 Limits of Usefulness This test procedure provides only a cumulative retur
22、n loss for components being tested. If the reflectance for individual components in series within a system must be analyzed, FOTP-8 should be used in lieu of this procedure. This procedure may be limited to testing components and fiberkable assemblies where the attached fiber can be placed in a mode
23、 filter or mandrel wrap. This test may not be able to be conducted on connectors or devices with fully enclosed fibers in a jacketed cable with a minimum bend radius greater than the mandrel wrap diameter. 2 Nor mat ive ref e re n ces Test of inspection requirements may include, but are not limited
24、to, the following references: E IA-440-A E I A/T I A-455-A FOTP-8 (ElA/TIA-455-8l1) FOTP-50 (EIA-455-50A) FOTP-54 (EIA/TIA-455-54A) FOTP-57 (EIA/TIA-455-57B2) FOTP-78 (EIA/TIA-455-78A) FOTP-I 80 (EIA/TIA-455-180) Fiber optic terminology Standard test procedures for fiber optic fibers, cables, transd
25、ucers, sensors, connecting and terminating devices, and other fiber optic components Measurement of splice or connector loss and reflectance using an OTDR Light launch conditions for long length graded-index optical fiber spectral attenuation measurements Mode scrambler requirements for over-filled
26、launching conditions for multimode fibers Optical fiber end preparation and examination Spectral attenuation cutback measurement for single-mode optical fibers Measurement of the optical transfer coefficients of a passive branching device (coupler) ) In the process of preparation. 2, In the process
27、of revision. Use EIA/TIA-455-57A until revision is complete. 2 Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TINEIA 455-1 07A 3 Apparatus The following apparatus and equipment
28、 are required to perform this test. 3.1 Optical power source The optical power source consists of a light source, either modulated or unmodulated, emitting wavelengths suitable for the devices tested as specified in the detail specification. The source power must be capable of meeting the dynamic ra
29、nge requirements of the measurement when combined with the detector sensitivity. Unless otherwise specified, light launch conditions shall be in accordance with FOTP-50, FOTP-54, or FOTP-78 (reference to these FOTPs does not preclude use of this procedu re for step-index fi bers). The stability of t
30、he source shall be sufficient to achieve the required accuracy. Unless otherwise specified in the detail specification, the power launched into the component must not be at such a high level as to generate non-linear scattering at levels higher than 10 dB below the level of test sensitivity desired.
31、 A light-emitting diode (LED) or an injection laser having the required radiation band are examples of sources which may be specified. Wavelength-selective filters may be used if necessary to limit optical spectral width. Use of an isolator is optional, but is recommended for laser sources to ensure
32、 stable operation. The optical power source should not be a single-spectral-line laser. Single-spectral-line lasers may have a coherence length long enough to turn the test set-up into an interferometer. Additionally, if the Device Under Test (DUT) is sufficiently reflective, a narrow linewidth sour
33、ce may be destabilized. 3.2 Optical directional coupler The directional coupler (or splitter) may be of any convenient coupling ratio if the selected coupling ratio remains stable throughout the measurement procedure. Use of a three port (1x2) coupler is recommended. The coupler may have additional
34、inputs and outputs provided the unused leads are terminated in non-reflecting terminations. The coupler shall be polarization-insensitive to prevent any dependence on the angular position at which the DUT is connected. The coupler performance shall be characterized for insertion loss and directivity
35、 in accordance with FOTP-I80 for use in the calculations of Section 6. Characterization in accordance with FOTP-I 80 shall be for the same wavelength that return loss/reflectance is measured. 3 Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo r
36、eproduction or networking permitted without license from IHS-,-,-TINEIA 455-1 07A 3.3 Non-reflective termination The termination shall be an optical load which is fully absorbent and non-reflective (at least 20 dB below the desired level of test sensitivity) when applied to unconnected leads from th
37、e DUT, or to unused leads of the coupler. Index matching materials (gels or fluids) are normally acceptable terminations for this test. Mandrel wraps can also be utilized. Provide sufficient turns around a 1 O mm mandrel, unless otherwise specified in the detail specification, to achieve a minimum o
38、f 40 dB attenuation. Some connector polishing techniques are known to affect a fibers index of refraction. These techniques may result in a termination with reflectance in the -30 dB to -40 dB range when index matching materials are used to achieve a non-reflecting termination with a connector. If i
39、ndex matching materials are used, extreme care must be used to ensure the materials are removed completely from the connector upon completion of this procedure. Failure to do so could cause false readings and contamination of this or other connector ends. 3.4 Detector(s) This unit shall consist of a
40、n optical detector, its fiber pigtail (if any), and any associated detection electronics. The precise characteristics shall be compatible with the measurement requirements and shall be specified in the detail specification. The device shall be linear (to within 5% over the power levels to be measure
41、d) and stable to k 1% (0.05 dB) over the measurement period. The detector shall have a reconnection repeatability to within 0.05 dB. The detector shall have sufficient active area and be placed sufficiently close to the output to capture all of the light exiting the output fiber. The detector shall
42、have sufficient dynamic range to make the necessary measurement. The detector should be capable of handling bare fiber ends and, where applicable, connectorized ends. 3.5 Temporary joints Use extremely low loss, low reflectance and repeatable units since all connectors or splices used in the test wi
43、ll influence the test results. When practicable, fusion splices or low reflectance mechanical splices are recommended due to their low loss and low reflectance. The reflectance of the connection to Port 3 of the coupler shall, unless otherwise specified in the detail specification, have a reflectanc
44、e at least 20 dB below the minimum reflectance to be measured. Index matching materials are highly recommended for use at all interfaces not under test. 3.6 Data read-out/recording/processing devices Provide a means to collect the power readings as it is measured by the detector. If desired, provide
45、 a means to perform the calculations and to report the results at the end of the test. A computer-based system may be used to fulfill this data acquisition and analysis function. 4 Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction o
46、r networking permitted without license from IHS-,-,-TINEIA 455-1 07A 4 Sampling and specimens The test sample or Device Under Test (DUT) shall be that specified in the Detail Specification. 5 Procedure 5.1 General test requirements The following general requirements apply to Methods A and B as appro
47、priate. 5.1 .I Fiber end preparation Whenever a fiber is cut during the procedure steps which follow (for making termination or connections, or for preparing for temporary joints), properly prepare the cut fiber end following the requirements of FOTP-57 in order to obtain a smooth end and endface at
48、 the desired angle (typically 90) from the fiber axis. 5.1.2 In-line adapters When testing connectors, appropriate in-line adapters may be used as needed for connecting to power sources, detectors, etc., provided they meet the requirements of 3.5. 5.1.3 Index-matching materials To meet the requireme
49、nts of 3.5, index-matching materials are recommended for use at all interfaces and terminations not under test. 5.1.4 Application of source power and measurement of output power Whenever source power is applied or output power is measured, use the wavelength specified in the Detail Specification. 5.2 Method A. Determination of DUT return loss/reflectance using two detectors 5
