1、TINEIA STANDARD ANSI/TIA/EIA-455-157-1994 Approved: December 5, 1994 Reaffirmed: mly 18, 2000 FOTP-157 Measurement of Polarization Dependent Loss (PDL) of SingleMode Fiber Optic Components TINEIA-455457 MAY 1995 - TELECOMMUNICATIONS INDUSTRY ASSOCIATION /- Representing the tekcommuuimions indoniy in
2、 iuoci11i0rI wiIh the ElecImnic IndusInes Aiinnec Elartionic Industrisa Alliance Copyright Electronic Industries Alliance Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NOTICE TLAIEL4 Engineering Standards and Publications are
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6、, nor 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 appropriat
7、e safety and health practices and to determine the applicability of regulatory limitations before its use. (From Standards Proposal No. 4639, formulated under the cognizance of the TIA FO-6.3 Subcommittee on Fiber Optic Interconnecting Devices.) This Document was reaffirmed by the American National
8、Standards Institute (ANSI) on July 18,2000, and by the TIA. Published by TELECOMMUNICATIONS INDUSTRY ASSOCIATION 1994 Standards and Technology Department 2500 Wilson Boulevard Arlington, VA 22201 PRICE: Please refer to current Catalog of PUBLICATIONS or call Global Engineering Documents, USA and Can
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11、HS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Copyright Electronic Industries Alliance Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TINEIA-455-1 57 FOTP-157 Measu
12、rement of polarization dependent loss (PDL) of single-mode fiber optic components Contents Foreword . introduction Applicable documents . Apparatus . Sampling and specimens . Procedure Calculations or interpretation of results . Documentation . Specification information Annex A . Comparison between
13、FOTP-157 and IEC. ISO. and ITU requirements iii 1 2 3 6 6 10 11 11 12 i Copyright Electronic Industries Alliance Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TINEIA-455-1 57 This page left blank. ii Copyright Electronic Indu
14、stries Alliance Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TINEIA-455-1 57 FOTP-I 57 Measurement of polarization dependent loss (PDL) of single-mode fiber optic components Foreword (This Foreword is informative only and is
15、 not part of this Standard.) This test procedure is from TIA Standards Proposal No. 3099, formulated under the cognizance of TIA FO-6.3, Subcommittee on Interconnecting Devices) This FOTP forms a part of the series of test procedures included within Recommended Standard EIATIA-455. There is one anne
16、x, which is informative. Key words: polarization dependent loss, polarization, all states, linear. iii Copyright Electronic Industries Alliance Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TINEIA-455-1 57 This page left blan
17、k. iv Copyright Electronic Industries Alliance Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TINEIA-455-1 57 1 Introduction 1.1 Intent The intent of this test is to determine the sensitivity of single-mode fiber optic compone
18、nts to changes in polarization. 1.2 Scope This procedure can be applied to any single-mode passive component, including connectors, splices, couplers, attenuators, isolators and switches. It is used to measure the total range of insertion loss, da, due. to changes in polarization of the launch state
19、. This procedure can also be used to measure the polarization dependence of isolated ports. For branching devices, it can also be used to measure the total range of coupling ratio, ACR(i). It cannot be used to measure polarization maintaining components or to measure the polarization dependence of r
20、eturn loss. Two methods for measuring the polarization dependence are described. Method A will determine the maximum polarization sensitivity over all possible polarization states including linear, circular and elliptical. Method B will determine the maximum polarization sensitivity over all linearl
21、y polarized launch states. Method A is preferred, particularly for any device in which the polarization state of light passing through the device is changed. If Method 6 is used, characterization using all polarization states is recommended to ensure that it is adequate for a particular component. M
22、ethod B will generally understate the polarization sensitivity of devices which are not dependent on linearly polarized light. Therefore, it is not recommended for tests where the device under test (DUT) has not been characterized to be sensitive to purely linear polarized light. 1.3 Description 1.3
23、.1 Method A Light is launched into the input port of the device under test such that linear, circular, and elliptical states of polarization with different axes of orientation can be adjusted while the power from the output port is monitored. The input power is also monitored by tapping some of the
24、power through a polarization- independent branching device. By adjusting for the maximum and minimum power through the component, the polarization sensitivity of the insertion loss can be obtained. For branching devices, it can also be used to measure the total range of coupling ratio. 1 Copyright E
25、lectronic Industries Alliance Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TINEIA-455-1 57 1.3.2 Method B Linearly polarized light is injected into the launch end of the (DUT). The launch lead of the device shall be deployed
26、 in a straight line without any external stresses, e.g. bends, twists, kinks, or tension. This is necessary because the state of polarization carried in the fiber is altered by external stresses.l The return leads may be deployed with bends as long as they are large enough not to induce bend loss (e
27、.g., bend diameters greater than 90 mm, or approximately 3.6 inches). If the state of polarization is altered by a bend in the output optical path, the polarization dependent loss should not be altered since there are no polarization sensitive components in the output optical path. The linear state
28、of polarization of the launch is typically rotated through a minimum of 180“ while the power from the output of the device under test is measured. If the launch power varies as a function of the launched state of linear polarization, this variation may be referenced out. The power from the source ma
29、y be measured through an equivalent 180“ cycle using a cut-back length from the input of the device under test or using an equivalent length of fiber similar to the device under test in substitution, as long as equivalence to the cutback measurement can be demonstrated. 2 Applicable documents The fo
30、llowing documents form a part of this FOTP to the extent specified herein: E IA-440-A . E I A/TI A-455-A FOTP-34 (EIMIA-455-34) FOTP-77 (ElMIA-455-77) FOTP-171 (EIMIA-455-1 71) FOTP-180 (EIA/TIA-455-180) Fiber Optic Terminology Standard Test Procedures for Fiber Optic Fibers, Cables, Transducers, Se
31、nsors, Connecting and Terminating Devices, and Other Fiber Optic Components Interconnection Device Insertion Loss Tests Fabricating and Qualifying a Higher-Order Mode Filter for Single-Mode Fiber Measurements Attenuation by Substitution Measurement - for Short-Length Multimode Graded-Index and Singl
32、e-Mode Optical Fiber Cable Assemblies Measurement of the Optical Transfer Coefficients of a Passive Branching Device (Coupler) Rashleigh,R.C., “Origins and Control of Polarization Effect in Single-Mode Fiber,“ Joumd of Lightwave Technology, vol, LT1 #2, June 1983, pp 312-331 2 Copyright Electronic I
33、ndustries Alliance Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-I TINEIA-455-1 57 3 Apparatus The following apparatus and equipment are required to perform this test: 3.1 Optical source An optical source capable of producing
34、 the spectral characteristics defined in the detail specification (both wavelength and spectral width) shall be used. Unless otherwise specified in the Detail Specification, the spectral width shall be less than 10 nm. The source power must be capable of meeting the dynamic range requirements of the
35、 measurement when combined with the detector sensitivity. The power, polarization state, and wavelength stability of the source shall be sufficient to achieve the desired measurement accuracy over the course of the measurement. An example of such a source is a tungsten bulb combined with a spectrall
36、y filtering monochromator. For some applications, a narrow linewidth source such as a single longitudinal mode laser may be used. This may be important for isolation measurements. NOTE: Multimode lasers may not provide sufficient polarization stability required for this measurement . 3.2 Excitation
37、unit (E) This unit consists of a passive optical system which transmits the optical power to the component. Means shall be provided to ensure that the DUT is single- moded at the wavelength of the measurement. A bend in the output pigtail of the DUT may be used to filter any second order mode power.
38、 An example of a higher order mode filter is defined in FOTP-77. 3.3 Temporary joint (TJ) This is a method, device, or mechanical fixture for temporarily aligning two fiber ends into a reproducible, low loss joint. This may be a direct optical launch into the pigtail or a splice onto the sources pig
39、tail. Typically, a fusion splice is used after the polarization adjuster since mechanical splices may exhibit some polarization sensitivity if the endfaces are not perpendicular to the fiber axis. The stability of the temporary joint shall be compatible with the required measurement precision. 3.4 P
40、olarization adjuster The source must be polarized to at least 10-2 extinction ratio unless otherwise specified in the Detail Specification. If the source is not already polarized to this level, use a polarizer to maintain this extinction ratio over the range of wavelengths of the measurement. 3 Copy
41、right Electronic Industries Alliance Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TINEIA-455-1 57 w- Mo nochromato r 3.4.1 Method A Provide a means to reproducibly adjust the polarization of the launch through all possible s
42、tates. The alignment of the system shall be adequate to ensure the reproducibility of launched power for the same orientation of the polarizer. The example in Figure 1 shows a linear polarizer (P), a half-wave retardation plate (H), and a quarter-wave retardation plate (Q) mounted on rotation stages
43、 and inserted into a collimated optical path produced at the output of the monochromator. Other means to reproducibly adjust the state of polarization are permitted, e.g. in-line fiber polarization controllers or other polarization instrumentation. Among the alternative methods of polarization adjus
44、tment, one design entails coiling a length of optical fiber around a circular paddle2, in such a way.as to minimize bending loss while inducing birefringence to create a fiber wave plate. Adjusting the number of turns about the paddle, and the radius of the paddle, controls the relative retardation
45、thereby producing half or quarter wave plates. Rotation of the paddle about an axis co-linear with the incoming/outgoing fiber and parallel to the diameter of the paddle is equivalent to the conventional means of rotating a wave plate. Additional paddles may be required to increase the spectral oper
46、ating range of the polarization adjuster. Note that this method requires the use of a source with a high degree of polarization and verification of the measurement precision may be required. P HQ Rotation Stages XYZ Translation Stage Figure 1 - Launch Apparatus Example for Method A 3.4.2 Method B Pr
47、ovide a means to launch linearly polarized light and rotate it through at least 180. The alignment of the system shall be adequate to ensure the reproducibility of launched power for the same orientation of the polarizer. The example in Figure 2 shows a linear polarizer (P) and a half-wave retardati
48、on plate (H) mounted on rotation stages and inserted into the collimated optical path produced at the output of the monochromator. Other means to reproducibly rotate the state of polarization are permitted, e.g. in-line fiber polarization controllers or other polarization instrumentation. See 3.4.1
49、for a brief description of one technique. 2H.C. Lefevre, Electronic Letters, September 25, 1980, Volume 16, Number 20, Pages 778-781. 4 Copyright Electronic Industries Alliance Provided by IHS under license with EIANot for ResaleNo reproduction or networking permitted without license from IHS-,-,-TINEIA-455-1 57 PH H-p i 0 07z,Mount Monochromator Lamp no Rotation Stages
