1、 ANSI/TIA/EIA-455-201-2001 Approved: August 8, 2001 TIA/EIA STANDARD TIA/EIA-455-201 FOTP-201 Return Loss of Connectorized Polarization-Maintaining Fiber or Polarizing Fiber Pigtailed Devices and Cable Assemblies TIA/EIA-455-201 AUGUST 2001 TELECOMMUNICATIONS INDUSTRY ASSOCIATION The Telecommunicati
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6、or does it assume any obligation whatever to parties adopting the Standard or Publication. 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 s
7、afety and health practices and to determine the applicability of regulatory limitations before its use. (From Standards Proposal No. 3-4246, formulated under the cognizance of the TIA FO-6.9 Subcommittee on Polarization Maintaining Fibers, Connectors, and Components) Published by g211TELECOMMUNICATI
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11、-854-7179, International (303) 397-7956 Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Copyright Telecommunications Industry Association Provided by IHS under license with EIAN
12、ot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TIA/EIA-455-201iContents1. Introduction . 12. Normative references 33. Apparatus 34. Sampling and specimens . 75. Procedure . 76. Calculation or interpretation of results 117. Documentation 118. Specification informati
13、on 12ANNEX A. Comparison between this standard and other TIA, IEC or ITU standards13Figure 1. Types of Polarization-Maintaining Fiber 2Figure 2. Steps 5.5 through 5.6 . 9Figure 3. Steps 5.7 and 5.8 9Figure 4. Steps 5.9 and 5.10 10Table 1. Wavelength Requirements Of Optical Power Source 4Copyright Te
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15、 reproduction or networking permitted without license from IHS-,-,-TIA/EIA-455-201iii_Foreword_This Standard comes from TIA Project No. 4246 and was formulated under thecognizance of TIA subcommittee FO-6.9.This FOTP is part of a series of test procedures included within RecommendedStandard TIA/EIA-
16、455.This Standard describes a new test method. There is one informative annex to thisStandard.Key words: polarization-maintaining fiber, polarizing fiber, PMF, PZF, return loss, backreflection, interconnection device.Copyright Telecommunications Industry Association Provided by IHS under license wit
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18、EIA-455-2011FOTP-201Return Loss of ConnectorizedPolarization-Maintaining or Polarizing FiberPigtailed Devices or Cable Assemblies_1. Introduction_1.1 IntentThis Standard specifies a procedure for the measurement of the return loss of afiber optic interconnection on single mode, highly linearly biref
19、ringent opticalfiber, i.e. either polarization-maintaining (PM) fiber or polarizing (PZ) fiber. Theconnector can be mounted on the PMF/PZF pigtail of a component or part of acable assembly. Return loss, as used in this Standard, is the ratio of powerincident on, or entering the DUT, to the total pow
20、er reflected by the DUT,expressed in decibels. The method described in this Standard is the PMF/PZFequivalent of ANSI/TIA/EIA-455-107 with the return loss reported as a positivenumber.Alternately, this measurement is sometimes called “reflectance” for which thevalues are simply the negative of retur
21、n loss. Thus, “reflectance” is the ratio indecibels of the power reflected by the DUT, to the power incident on, or enteringthe DUT. The preferred terminology is “return loss” as will be used throughoutthe rest of this Standard.1.2 DefinitionsFor the purposes of this Standard, the following definiti
22、ons apply.Birefringence. The property of a material in which orthogonal light polarizationshave different indices of refraction, which cause the light at those polarizationsto travel at different speeds (also referred to as the fast and slow axes). Linearlybirefringent fiber maintains linear polariz
23、ation states along the length of the fiber.Unstable birefringence in standard single-mode fiber causes the states ofpolarization to behave in an unpredictable way. Polarization-maintaining fibersare a special class of single-mode fibers with a highly birefringent waveguidestructure that maintain the
24、 polarization states across the length of the fiber.Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TIA/EIA-455-2012Polarization-Maintaining Fiber (PMF). A class of highly linea
25、rly birefringentsingle-mode fiber, unlike the common variety of low birefringence, single-modefiber used in telecommunication networks. PMF is used to guide linearlypolarized light from point to point, that is, to ensure that polarization does notchange with distance. As shown in Figure 1, the biref
26、ringence of commercialPMF is stress-induced by placing the core between or within glass elements ofdifferent physical composition, or by forming a non-round core.Polarizing Fiber (PZF). A highly birefringent optical fiber in which only onepolarization state is propagated with low attenuation.Princip
27、al Optical Axes. Those optical axes for which the speed of light in alinearly birefringent material is a maximum or a minimum.Slow Axis. The optical axis of a PMF or PZF which is aligned to the stress rods(as in PANDA or Bow-tie fiber), the stress region (as in Oval stress region fiber),or the major
28、 axis of an elliptical core fiber. For PMF to be actually polarizationmaintaining, linearly polarized light must be aligned with one of the axes,commonly the slow axis. By convention, the anti-rotation key of the connectorshould be aligned with the slow axis as defined in FOCIS-4A and to be followed
29、for other connector types, as shown in Figure 1.Fast Axis. The optical axis of a PMF or PZF which is orthogonal to the slowaxis. See Figure 1.Panda Bow TieOvalCoreOval StressRegionSlow axis(Aligned WithConnector Key)FastAxisFigure 1. Types of Polarization-Maintaining FiberDevice Under Test (DUT). Th
30、e specimen, or device, under test.Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TIA/EIA-455-20132. Normative references_The following standards contain provisions, which, thro
31、ugh reference in this text,constitute provisions of this Standard. At the time of publication, the editionsindicated were valid. All standards are subject to revision, and parties toagreements based on this Standard are encouraged to investigate the possibilityof applying the most recent editions of
32、 the standards indicated below. ANSI andTIA maintain registers of currently valid national standards published by them.ANSI/TIA/EIA 440-A Fiber Optic TerminologyANSI/TIA/EIA 455-A Standard Test Procedure for Fiber Optic Fibers, Cables, Transducers, Sensors, Connecting and Terminating Devices, and Ot
33、her Fiber Optic ComponentsANSI/TIA/EIA 455-80 FOTP-80, Cut-off Wavelength MeasurementProcedureANSI/TIA/EIA 455-107A FOTP-107, Determination of Component Reflectanceor Link/System Return Los Using a Loss Test SetANSI/TIA/EIA 455-180 FOTP-180, Measurement of the optical transfercoefficients of a passi
34、ve branching device (coupler)ANSI/TIA/EIA 604 Fiber Optic Connector Intermateability StandardANSI/TIA/EIA 604-4A FOCIS 4A, Fiber Optic Connector IntermateabilityStandard Type FC with APC and PolarizationMaintaining RequirementsTELCORDIA GR-326-CORE Generic Specification for Single ModeConnectors and
35、 Cable Assemblies (Issue 3)_3. Apparatus_The following apparatus and equipment are required to perform this test.Copyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TIA/EIA-455-2014
36、3.1 Optical light sourceThe optical power source shall be a diode laser, either modulated orunmodulated, whose center wavelength and spectral width shall be within theparameters provided in Table 1, unless otherwise specified in the DetailSpecification. In addition, the source shall not emit more th
37、an 0.1% (-30dB) ofits optical power at wavelengths shorter than the cutoff wavelength (per FOTP-80) of any of the fibers (SMF/PMF/PZF) incorporated in the measurementapparatus.Table 1. Wavelength Requirements Of Optical Power SourceNominal Wavelength Center Wavelength RMS Spectral Width1310nm 1310nm
38、 +/- 30nm 5nm1550nm 1550nm +/- 30nm 5nmThe optical power of the light source must either be stable over the duration ofthe test or normalized by means of a reference. Without a reference, theuncontrolled variation in source power must be less than 1% (0.05 dB) duringthe measurement.The source power
39、must be capable of meeting the dynamic range requirementsof the measurement when combined with the detector sensitivity. In addition,the power launched into the component must not be at such a high level as toinduce non-linear scattering at levels higher than 10 dB below the level of testsensitivity
40、 desired. Use of an isolator is optional, but is recommended for lasersources to ensure 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 testset-up into an interferometer. Additionall
41、y, if the Device Under Test (DUT) issufficiently reflective, a narrow line width source may be destabilized.3.2 Single-mode optical directional couplerThe coupler shall be fabricated from non-PMF/PZF single-mode fiber whosecore diameter, numerical aperture and cut-off wavelength most closely matches
42、the PMF/PZF of the DUT. The coupler shall also be polarization insensitive toprevent any dependence on the angular position at which the DUT is connected.The directional coupler (or splitter) may be of any convenient coupling ratio if theselecting coupling ration remains stable throughout the measur
43、ementprocedure. Use of a three port (1x2) coupler is recommended. The coupler mayCopyright Telecommunications Industry Association Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TIA/EIA-455-2015have additional inputs and outpu
44、ts provided the unused leads are terminated innon-reflecting terminations.The coupler performance shall be characterized for insertion loss and directivityin accordance with FOTP-180 for use in the calculations of Section 6.Characterization in accordance with FOTP-180 shall be for the same wavelengt
45、hthat return loss/reflectance is measured.3.3 Non-reflective terminationThe termination shall be an optical load which is fully absorbent and non-reflective (at least 6 dB above the minimum acceptance level of the DUT) whenapplied to unconnected leads from the DUT, or to unused leads of the coupler.
46、Index-matching materials (gels or fluids) are normally acceptable terminationsfor this test. Mandrel wraps can also be utilized. Provide sufficient turns arounda 10mm mandrel, or other suitable method, to achieve minimum of 40 dBattenuation.Some connector polishing techniques are known to affect a f
47、ibers index ofrefraction. These techniques may result in a termination with return loss in the40 dB to 50 dB range when index-matching materials are used to achieve a non-reflecting termination with a connector. If index-matching materials and/or othernear-zero reflecting terminations are used, extreme care must be used to ensurethe materials are removed completely from the connector upon completion ofthis procedure. Failure to do so could cause false readings and contaminationof this or other connector ends.3
