«WORKMANSHIP STANDARD FOR FIBER OPTIC TERMINATIONS, CABLE ASSEMBLIES, AND INSTALLATION Measurement System Identification: Metric (English) NASA-STD ...»
National Aeronautics and Space Administration
Washington, DC 20546
With Change 2
WORKMANSHIP STANDARD FOR FIBER OPTIC
TERMINATIONS, CABLE ASSEMBLIES, AND
Measurement System Identification:
Metric (English) NASA-STD 8739.5A – September 14, 2015 This page intentionally left blank.
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DOCUMENT HISTORY LOGDocument Status Approval Date Description Revision Baseline 1998-02-09 Initial Release Update references, add ‘requirement’ tags, and revalidate Change 1 2008-07-25 (JWL4) Editorial corrections to Foreword and paragraph 9.2.c.
Format Page numbers. Add reference to NASA-STD Change 2 2011-03-29
8709.22 in paragraphs 2.1.2 and 3.2.
(JWL4) The Workmanship Standard for Fiber Optic Terminations, Cable Assemblies, and Installation, NASA-STD-8739.5,
was revised to:
a. Reflect current NASA standards formatting b. Update language for seeking relief from the stated Revision A 2015-09-15 requirements c. Make it consistent with NASA-STD-8739.6 d. Implement other clarifications and corrections (JFP) Page 3 of 43 NASA-STD 8739.5A – September 14, 2015 This page intentionally left blank.
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FOREWORDThis Standard is published by the National Aeronautics and Space Administration (NASA) to provide uniform engineering and technical requirements for processes, procedures, practices, and methods that have been endorsed as standard for NASA programs and projects, including requirements for selection, application, and design criteria of an item.
This Standard is approved for use by NASA Headquarters and NASA Centers, including Component Facilities and Technical and Service Support Centers, and is intended to be applied on NASA contracts.
This Standard prescribes NASA’s process and end-item requirements for reliable fiber optic terminations, cables, assemblies, and the installation thereof.
This NASA-STD was developed by NASA Headquarters Office of Safety and Mission Assurance and the NASA Workmanship Standards Program. Requests for information, corrections, or additions to this Standard should be submitted to the National Aeronautics and Space Administration, Director, Safety and Assurance Requirements Division, Office of Safety and Mission Assurance, Washington, DC 20546 or via “Feedback” in the NASA Standards and Technical Assistance Resource Tool at http://standards.nasa.gov.
DOCUMENT HISTORY LOG
DEFINITIONS AND ACRONYMS
Abbreviations and Acronyms
Definitions Used in this Standard
TRAINING AND CERTIFICATION PROGRAM
FACILITIES, EQUIPMENT AND MATERIALS
Tools and Equipment
Storage and Handling
Parts and Materials Selection
Material Shelf Life Requirements
OPTICAL FIBER END PREPARATION
FIBER OPTIC SPLICING
FIBER OPTIC CABLE ASSEMBLIES
Post Assembly Testing
FIBER OPTIC ASSEMBLIES
Fiber Optic Connector Termination
Post Fiber Optic Connector Termination
Fiber Optic Routing
Fiber Optic Assembly Testing
FIBER OPTIC CABLE ASSEMBLY INSTALLATION
Design Requirements and Considerations for Fiber Optic Assembly Installation...... 34
QUALITY ASSURANCE PROVISIONS
APPENDIX A............... FIBER END-FACE INSPECTION CRITERIA AFTER POLISHING
APPENDIX B. TEST METHODS FOR THE VERIFICATION OF OPTICALFIBER FABRICATION PROCESSES
Figure 7-1. Parts of a Typical Optic Cable
Figure A-1. Bare Fiber - Back-Lit
Figure A-2. Bare Fiber - Back-Lit - Continued
Figure A-3. Fiber in Ferrule - Back-Lit
Figure A-4. Fiber in Ferrule - Back-Lit - Continued
Figure A-5. Fiber in Ferrule - Direct-Lit, No Core Illumination
FIBER OPTIC TERMINATIONS, CABLE ASSEMBLIES, AND INSTALLATIONSCOPE Purpose This Standard sets forth termination and cabling requirements for optical fiber and cable assemblies.
Applicability This Standard is approved for use by NASA Headquarters and NASA Centers, including Component Facilities, and Technical and Service Support Centers, and may be cited in contract, program, and other Agency documents as a technical requirement. This Standard may also apply to the Jet Propulsion Laboratory other contractors, grant recipients, or parties to agreements only to the extent specified or referenced in their contracts, grants, or agreements.
This standard applies to critical work, as defined by NPD 8730.5. Critical work is any task that if performed incorrectly or in violation of prescribed requirements poses a credible risk of loss of human life; serious injury; loss of a Class A, B, or C payload (see NPR 8705.4); loss of a Category 1 or Category 2 mission (see NPR 7120.5); or loss of a mission resource valued at greater than $2M (e.g., NASA space flight hardware, Government test or launch facility).
For payload installation operations where Technical Order 1-1A-14, Installation and Repair Practices, Aircraft Electric and Electronic Wiring, is the baseline or primary design and quality standard, the applicable requirements herein are limited to those in Chapter 12, Fiber Optic Cable Assembly Installation.
Use of the term “supplier” applies to any entity who is manufacturing hardware in accordance with the requirements herein including NASA Centers and NASA contractors.
APPLICABLE DOCUMENTSGeneral The documents listed in this section contain provisions that constitute requirements of this Standard as cited in the text. The applicable documents are accessible via the NASA Standards and Technical Assistance Resource Tool at http://standards.nasa.gov or may be obtained directly from the Standards Developing Organizations or other document distributors.
NASA POLICY DOCUMENTS AND SPECIFICATIONS:
Definitions Used in this Standard Note: Definitions for SMA terms are found in NASA-STD 8709.22, Safety and Mission Assurance Acronyms, Abbreviations, and Definitions. Terms unique to this NASA-STD are listed below. Additional related terms and definitions can be found in EIA/TIA-440, Fiber Optic Terminology.
Adhesive: A polymeric compound, usually an epoxy, used to secure the optical fiber in a splice assembly or connector.
Back-lit: A method of illuminating the fiber end-face by launching incoherent light into the optical fiber core through the opposite end of the fiber.
Backscatter: The return of a portion of scattered light to the input end of a fiber; the scattering of light in the direction opposite to its original propagation.
Buffer: A material applied over the coating that may be used to protect an optical fiber from physical damage, providing mechanical isolation or protection, or both.
Bend Radius, Long Term: The minimum radius to which a cable, without tensile load, can be bent for its lifetime without causing broken fibers, a localized weakening of the fibers, or a permanent increase in attenuation.
Page 11 of 43 NASA-STD 8739.5A – September 14, 2015 Bend Radius, Short Term: The minimum radius to which a cable can be bent while under the maximum installation load without causing broken fibers, a localized weakening of the fibers, or a permanent increase in cable attenuation.
Cladding: The dielectric material surrounding the core of an optical fiber.
Cleave: The process of separating an optical fiber by a controlled fracture of the glass for the purpose of obtaining a fiber end that is flat, smooth, and perpendicular to the fiber axis.
Coating: A material put on a fiber during the drawing process to protect it from the environment.
Coupling Loss: The optical power loss suffered when light is coupled from one optical device to another.
Degas: The removal of entrapped bubbles from a viscous fluid by placing that fluid in a centrifuge or vacuum.
Direct-lit: A method of illuminating the fiber end-face by projecting a light source onto the fiber.
Ferrule: A mechanical fixture, generally a rigid tube, used to confine the stripped end of a fiber bundle or an optical fiber.
Fiber (Optical): A filament shaped optical waveguide made of dielectric material.
Fiber Optic Cable: A fiber, multiple fiber or fiber bundle in a cable structure fabricated to meet optical mechanical and environmental specifications.
Fiber Optic Connector: A fiber optic component normally assembled onto a cable and attached to a piece of apparatus for the purpose of providing interconnecting/disconnecting of fiber optic cables.
Glass Transition Temperature (Tg): The temperature above which an amorphous polymer displays viscous behavior caused by chain slip.
Insertion Loss: The optical attenuation caused by the insertion of an extra optical component into an optical system.
Installation Load, maximum: The maximum load which can be applied along the axis of a cable during installation without breaking fibers or causing a permanent increase in the cable attenuation.
Interferometer: An instrument that employs the interference of light waves for purposes of measurement.
Laser: A device that produces coherent optical radiation by stimulated emission and amplification.
Mode: In general, an electromagnetic field distribution that depends on wavelength of light and material properties of the traveling medium. In guided wave propagation, such as through a waveguide or optical fiber, a distribution of electromagnetic energy that satisfies Maxwell's Page 12 of 43 NASA-STD 8739.5A – September 14, 2015 equations and boundary conditions. In terms of ray optics, a possible path followed by light rays dependent on index of refraction, wavelength of light and waveguide dimensions.
Multi-mode Fiber: An optical fiber that will allow two or more bound modes to propagate in the core at the wavelengths of interest.
Optical Time Domain Reflectometry (OTDR) Backscattering Technique: A method for characterizing an optical fiber whereby an optical pulse is transmitted through the fiber and the optical power of the resulting light scattered and reflected back to the input is measured as a function of time.
Pistoning: The axial movement of an optical fiber within a connector or connector ferrule.
Refraction: The bending of a beam of light in transmission through an interface between two dissimilar media or in a medium whose refractive index is a continuous function of position, for example graded index medium.
Repair: Action on a nonconforming product to make it acceptable for the intended use.
Rework: Action on a nonconforming product to make it conform to the requirements.
Single-Mode Fiber: An optical fiber in which only the lowest order bound mode can propagate at the wavelength of interest.