SAE AIR 6162-2017 Fusion Splicing for Optical Fibers.pdf

1、_ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising there

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3、ublication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-497

4、0 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/standards.sae.org/AIR6162 AEROSPACE INFORMATION REPORT AIR6162 Issued 2017-04 Fusion Splicing for Optical Fibers

5、RATIONALE The aerospace industry has successfully integrated fiber optics as a viable technology for transmission of light. Fiber optic connectors, both for new connections and field repairs, continue to present issues with acquisition and life cycle costs. Fusion splices can be used for permanent f

6、iber connections with a significant reduction in cost and improvement in loss and stability. Another application being discussed is the use of fusion splicing to splice pre-installed fiber optic cable assemblies onto pigtailed connectors, allowing non-terminated cables to be easily routed into a str

7、ucture and terminated during the final assembly phase. Specifically designed fusion splicers can be used in explosive environments found in aerospace. TABLE OF CONTENTS 1. SCOPE 5 2. REFERENCES 5 2.1 Applicable Documents 5 2.1.1 SAE Publications . 5 2.1.2 Military Specifications 5 2.1.3 Military Sta

8、ndards 5 2.1.4 ANSI Accredited Publications 6 2.1.5 Aeronautical Radio (ARINC) AEEC Committee, Fiber Optics Subcommittee (FOS) Publications . 6 2.1.6 Comit Europan de Normalisation (CEN) Publications . 6 2.1.7 IEC Publications 6 2.1.8 International Telecommunications Union Publications 6 2.1.9 Radio

9、 Technical Commission for Aeronautics (RTCA) Publications. 6 2.1.10 Telcordia Publications . 6 2.1.11 TIA/EIA Publications 7 2.1.12 Other Documents 7 2.2 Acronyms 8 3. BASIC FUSION SPLICING . 8 3.1 History . 8 3.2 Why Fusion Splicing? 10 4. THE FUSION SPLICING PROCESS 10 4.1 Fiber Preparation . 10 4

10、.1.1 Preparation 11 4.1.2 Cleaning 14 4.1.3 Cleaving the Optical Fiber . 15 4.2 Optical Fiber Fusion Splicer 17 4.3 Optical Fiber Alignment . 18 4.4 Arc Fusion . 20 4.5 Fusion Splicing Process 21 SAE INTERNATIONAL AIR6162 Page 2 of 52 4.6 Thermal Management and Profiles . 24 4.6.1 Mismatched Optical

11、 Fibers 24 4.7 Proof Test 24 4.8 Loss Estimation . 25 5. SPLICE PROTECTION AND RELIABILITY 26 5.1 Splice Protection . 26 5.2 Fiber Recoating . 27 5.3 Cable Restoration 28 5.4 Fusion Splices Enclosures 29 5.5 Reliability of Fusion Splices . 29 6. SPLICE LOSS EXPECTATIONS 32 6.1 Statistics of Single M

12、ode Optical Fiber Splice Loss 32 6.2 Statistics of Multi-Mode Optical Fiber Splice Loss 32 6.3 Factors Affecting Splice Reliability 33 7. OPTICAL FIBER AND MATERIAL COMPATIBILITY . 35 7.1 Optical Fiber Diameters, Coatings, and Fiber Optic Cables . 35 7.2 Polarization Maintaining (PM) Optical Fibers

13、36 7.3 Dispersion Compensating Optical Fibers 38 7.4 Amplifier and Laser Optical Fibers 39 7.5 Nonlinear Optical Fibers 39 7.6 Microstructured (PCF) Optical Fibers 39 7.7 Bend Insensitive Optical Fibers . 41 7.8 Hydrogen Loaded Optical Fibers . 41 7.9 High Temperature Optical Fibers 42 7.10 Non-Circ

14、ular Optical Fibers . 42 7.11 Radiation Tolerant Optical Fibers 42 7.12 Large Diameter Optical Fibers 42 7.13 Fluoride Optical Fiber 43 8. SPECIAL SPLICER FEATURES . 43 8.1 Field Splicers . 43 8.2 Laboratory Splicers . 44 8.3 Ribbon Splicers . 45 9. SPECIAL DEVICES FABRICATION BY FUSION SPLICERS 46

15、9.1 Splice-On Connectors . 46 9.2 Long Period Gratings 46 9.3 Tapers/Mode Field Expansion/Probes 47 9.4 Attenuators or In-Line Attenuation Splices 48 9.5 Interferometers 50 9.6 Ball Lenses 50 9.7 Fiber Scanning Systems . 50 9.8 Fiber Alignment Systems for Testing Fibers and Pigtailed Components 50 9

16、.9 Fiber Cleaning . 51 9.10 Fiber End Polishing . 51 10. NOTES 52 10.1 Revision Indicator 52 SAE INTERNATIONAL AIR6162 Page 3 of 52 FIGURE 1 BASIC FIBER CONSTRUCTION WITH PRIMARY AND SECONDARY COATINGS/BUFFERS 10 FIGURE 2 TIGHT BUFFER VERSUS LOOSE TUBE CABLE CONSTRUCTIONS . 11 FIGURE 3 REMOVING CABL

17、E JACKET WITH A STANDARD CABLE STRIPPER. 12 FIGURE 4 REMOVING A 900 M LOOSE BUFFER TUBE . 12 FIGURE 5 TWO DIFFERENT THERMAL STRIPPERS FOR REMOVING HARD-TO-REMOVE SECONDARY COATINGS 13 FIGURE 6 REMOVING 250 M ACRYLATE PRIMARY COATING (COURTESY THORLABS) . 13 FIGURE 7 EXAMPLE OF PLASMA COATING STRIP (

18、COURTESY SAE INTERNATIONAL) . 14 FIGURE 8 CLEANING THE OPTICAL FIBER BY WIPING WITH A LINT FREE WIPE MOISTENED WITH OPTICAL GRADE SOLVENT . 14 FIGURE 9 TYPICAL ULTRASONIC CLEANER FOR OPTICAL FIBERS (COURTESY AFL) . 15 FIGURE 10 CLEAVING AN OPTICAL FIBER WITH A PRECISION CLEAVER 15 FIGURE 11 ANOTHER

19、TYPICAL PRECISION SINGLE FIBER CLEAVER (COURTESY FUJIKURA) 16 FIGURE 12 ULTRASONIC PRECISION SINGLE FIBER CLEAVER (COURTESY ERICSSON/YORK) 16 FIGURE 13 PROCESS OF FIBER CLEAVING 17 FIGURE 14 PLACING A PREPARED OPTICAL FIBER IN ITS FIBER HOLDER OR “CLIP” INTO A FUSION SPLICER . 17 FIGURE 15 X AND Y V

20、IEW IMAGES OF TWO OPTICAL FIBERS BEING ALIGNED BY A FUSION SPLICER . 18 FIGURE 16 SCHEMATIC DIAGRAM OF X-Y ACTIVE FIBER ALIGNMENT. 19 FIGURE 17 OPTICAL FIBERS ALIGNED, READY FOR FUSION 19 FIGURE 18 TYPICAL VOLTAGE VERSUS CURRENT PROFILE DURING ARC DISCHARGE AND FUSION . 20 FIGURE 19 ARC FUSING TWO O

21、PTICAL FIBERS TOGETHER . 20 FIGURE 20 SCHEMATIC ILLUSTRATION OF THE PROFILE ALIGNMENT SYSTEM (PAS) METHOD OF FIBER INSPECTION AND ALIGNMENT 22 FIGURE 21 PAS SYSTEM DETECTION OF DEFECTIVE OPTICAL FIBER END PREPARATION . 22 FIGURE 22 RESULTS OF OPTICAL FIBER END ANGLE MEASUREMENTS 22 FIGURE 23 SCHEMAT

22、IC ILLUSTRATION OF THE LID METHOD OF FIBER ALIGNMENT . 23 FIGURE 24 SPLICING MISMATCHED FIBERS 24 FIGURE 25 PAS PROCESS OF INSERTION LOSS ESTIMATION 25 FIGURE 26 HEAT SHRINK SPLICE PROTECTION SLEEVES 26 FIGURE 27 HEAT OVEN FOR HEAT SHRINK SPLICE PROTECTION SLEEVES 26 FIGURE 28 SPLICE PROTECTOR SHRUN

23、K ONTO FIBER SPLICE . 27 FIGURE 29 A TYPICAL FIBER RECOATING SYSTEM 27 FIGURE 30 THE PROCESS OF FIBER OR FUSION SPLICE RECOATING . 28 FIGURE 31 CABLE SPLICE RESTORATION EXAMPLE 29 FIGURE 32 FUSION SPLICE ENCLOSURE EXAMPLE (COURTESY FIS) . 29 FIGURE 33 SPLICING RESULTS WITH FIELD-WORTHY FUSION SPLICE

24、R ON SMF . 32 FIGURE 34 SPLICING RESULTS WITH FIELD-WORTHY FUSION SPLICER ON MMF 33 FIGURE 35 SCHEMATIC ILLUSTRATION OF FIBER WEAKNESS AWAY FROM THE ACTUAL JOINT. 34 FIGURE 36 LOCATION OF MMF OPTICAL FIBER SPLICE BREAKS UNDER TENSION, RELATIVE TO THE POINT OF FUSION 34 FIGURE 37 SCHEMATIC ILLUSTRATI

25、ON OF SPLICE WEAKENING DUE TO MOISTURE 34 FIGURE 38 THREE BASIC STRESS-INDUCING CONFIGURATIONS FOR PM OPTICAL FIBER . 36 FIGURE 39 COMPARISON OF STRESS MEASUREMENTS VERSUS FIBER ROTATION FOR THREE PM OPTICAL FIBERS, COMPARED WITH SMF . 37 FIGURE 40 POLARIZATION-MAINTAINING FUSION SPLICER (COURTESY A

26、URORA OPTICS) 38 FIGURE 41 EXAMPLES OF SOLID CORE PHOTONIC CRYSTAL FIBER 40 FIGURE 42 DIAGRAM OF A PCF PREFORM STACK AND FIBER DRAW (A) PCF PREFORM IS CREATED BY STACKING GLASS RODS (B) PCF PREFORM IS DRAWN IN A FIBER DRAW TOWER (C) PARTIALLY DRAWN PCF PREFORM 40 FIGURE 43 (A) SAGNAC INTERFEROMETER

27、TEMPERATURE DEPENDENCE COMPARISON BETWEEN CONVENTIONAL PM FIBER AND PM-PCF (B) CROSS SECTION OF THE COMMERCIALLY AVAILABLE PURE SILICA PM-PCF USED IN THE EXPERIMENTATION . 41 FIGURE 44 IMAGE OF A TYPICAL FIELD FUSION SPLICER (COURTESY FURUKAWA) 43 FIGURE 45 FIELD FUSION SPLICER BEING USED ON A CLOSU

28、RE ON AERIAL STRAND 44 FIGURE 46 MINIATURE AUTOMATIC FIELD FUSION SPLICER RUGGEDIZED TO SAE STANDARD AS6479/2 . 44 FIGURE 47 TYPICAL LABORATORY OR PRODUCTION FUSION SPLICER (COURTESY FURUKAWA) 45 FIGURE 48 SCHEMATIC ILLUSTRATION OF MASS OR RIBBON FUSION SPLICING . 45 FIGURE 49 REPRESENTATIVE SPECTRU

29、M OF A LONG PERIOD GRATING 46 SAE INTERNATIONAL AIR6162 Page 4 of 52 FIGURE 50 DIAGRAM OF THE ARC-INDUCED LONG PERIOD GRATING WRITING PROCESS, MONITORED BY AN OPTICAL SPECTRUM ANALYZER (OSA) 47 FIGURE 51 CHARACTERISTIC HOUR GLASS SHAPE OF A TAPERED SPLICE 47 FIGURE 52 TAPERED FIBER JUST BEFORE TIP S

30、EPARATION . 48 FIGURE 53 SPLICE GEOMETRY OF AN ATTENUATOR 48 FIGURE 54 RELATIONSHIP BETWEEN ATTENUATION AND PRE-FUSION FIBER OFFSET FOR SINGLE MODE FIBERS . 49 FIGURE 55 BALL LENS MADE ON THE END OF A 600 M DIAMETER SILICA FIBER 50 FIGURE 56 PROTOTYPE PRECISION FIBER ALIGNMENT SYSTEM FOR COMPONENT T

31、ESTING WITH TEMPORARY INDEX-MATCHED JOINTS (COURTESY AURORA OPTICS) . 51 FIGURE 57 POLYIMIDE-COATED FIBER WITH CENTER PORTION ARC-CLEANED 51 TABLE 1 REMOVAL METHODS FOR HARD-TO-REMOVE COATINGS . 13 TABLE 2 REPRESENTATIVE PERFORMANCE DATA ON FUSION SPLICES AND RESTORATIONS ON MIL-SPEC SIMPLEX FIBER O

32、PTIC CABLES 30 TABLE 3 TYPICAL SPLICING CAPABILITIES OF FUSION SPLICERS DESIGNED FOR MIL/AERO APPLICATIONS 35 SAE INTERNATIONAL AIR6162 Page 5 of 52 1. SCOPE This document provides an orientation to fusion splicing technology for optical fibers and fiber optic cable. It is intended for managers, des

33、igners, installers, and repair and maintenance personnel who need to understand the process of fusion splicing. This technology is widely used in telecommunications and industrial applications, and is finding acceptance in aerospace applications. 2. REFERENCES 2.1 Applicable Documents 2.1.1 SAE Publ

34、ications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org. ARP5061 Guidelines for Testing and Support of Aerospace, Fiber Optic, Interconnect Systems AS5382 Aerospace Cable, Fiber

35、 Optic AS5675 Characterization and Requirements for New Aerospace Fiber Optic Cable Assemblies - Jumpers, End Face Geometry, Link Loss Measurement, and Inspection AS5750 Loss Budget Specification for Fiber Optic Links AIR6031 Fiber Optic Cleaning AIR6258 Fiber Optic Sensors for Aerospace Application

36、s AS6479 Splicer, Fusion, Fiber Optic, Aerospace 2.1.2 Military Specifications Copies of these documents are available online at http:/quicksearch.dla.mil. A-A-59799 Commercial Item Description: Fusion Splicer and Cleaver, Optical Fiber MIL-PRF-24623/6 Splice, Fusion, Fiber Optic Cable, Protector MI

37、L-PRF-24623/7 Splice, Mechanical, Simplex Fiber Optic Cable, Aircraft MIL-PRF-49291 Optical Fiber, (Metric) General Specification for MIL-PRF-85045 Cables, Fiber Optic, (Metric) General Specification for 2.1.3 Military Standards Copies of these documents are available online at http:/quicksearch.dla

38、.mil. MIL-STD-810G Environmental Engineering Considerations and Laboratory Tests MIL-STD-1678 Fiber Optics Test Methods and Instrumentation MIL-STD-46855 Human Engineering Requirements for Military Systems, Equipment, and Facilities NAVAIR 01-01A-505-4 Installation Demokan, M.S.; Wei Jin; Yiping Wan

39、g; Chun-liu Zhao, “Fusion Splicing Photonic Crystal Fibers and Conventional Single-Mode Fibers: Microhole Collapse Effect,“Lightwave Technology, Journal of, vol.25, no.11, pp.3563,3574, Nov. 2007. 4 Sanghera, J., Infrared Fiber Optics, CRC Press: Boca Raton, FL. 1998. SAE INTERNATIONAL AIR6162 Page

40、8 of 52 2.2 Acronyms CTE Coefficient of Thermal Expansion FBG Fiber Bragg Grating FW Fusion Welder IFOG Interferometric Fiber Optic Gyroscope kV Kilovolt LDF Large Diameter Fiber LID Local Injection And Detection LPD Long Period Grating MFD Mode Field Diameter MM Multimode MMF Multi-Mode Fiber OTDR

41、Optical Time Domain Reflectometer PAS Passive Alignment System PCF Photonics Crystal Fiber PM Polarization Maintaining SMF Single Mode Fiber TIG Tungsten Inert Gas (Welding) 3. BASIC FUSION SPLICING 3.1 History In the 1970s engineers realized that if optical fibers could be welded together, end-to-e

42、nd, superior splices could be achieved, with consistently low insertion loss and low back reflection. An early method tried was to align the two fibers with each other with micrometer-driver positioners, under a microscope, heat the two ends with a hydrogen torch, and push the ends together as quick

43、ly as possible. This method was used to install fiber cables for the Lake Placid Winter Olympic Games in 1976. With manual control, however, this was a very difficult process to perform successfully. Failures tended to outnumber successes. By 1978 IBM first published the results of experiments in fu

44、sing optical fibers with electric arcs. This was basically tungsten inert gas (TIG) welding, applied to silica fibers. Given precise alignment fixtures, an electric arc could be developed, applied, and controlled precisely enough in the lab to make good welded (fused) joints with reasonably high yie

45、ld. Engineers working at Sandia National Labs then converted the technique into a manufacturable product, forming a new company called Orionics Products. Orionics pioneered the first portable, self-contained, commercially-available arc fusion splicer; since the technique was based on TIG welding, th

46、ey named it “FW” for Fusion Welder. Fiber alignment was still performed manually by the user, but the heat was applied by a high voltage arc which was precisely controllable in time and current. Over the years the welding/fusion splicing technique has been repeatedly and highly refined: Precise v-gr

47、oove alignment to relieve the user from aligning manually Automatic precision optical fiber alignment mechanisms (piezoelectric) Automatic control of arc current and time Video imaging SAE INTERNATIONAL AIR6162 Page 9 of 52 Extension of the technique from multi-mode optical fibers to single mode opt

48、ical fibers Local Injection and Detection (LID) to allow power-peaking optical fiber alignment Image processing for automatic optical fiber alignment LID power processing for automatic optical fiber alignment Loss estimation based on image processing Loss estimation based on coupled power Splicing s

49、pecialty optical fibers (bend-resistant, PCF, Er-doped, large core, NZDF, small core (4 m), etc. Ever smaller and more rugged packages Rotational alignment and splicing of polarization-maintaining optical fibers Splicing several optical fibers at once, in parallel (e.g., 4, 8, 12, or 24) Splicing multi-core optical fibers Splicing high-power optical fibers (cores up to 1 mm) Splicing mismat