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  978-1-4577-1343-9/12/$26.00 ©2012 IEEE 1

Engineering of Fiber Optics Infrastructure

Abstract – Fiber optic technology is making significant

advances for use in a number of air and space platforms. Many

of these applications involve integration into systems which

make extensive use of optical fiber for high bandwidth signal

transmission. The large signal transmission bandwidth of

optical fiber has a large and positive impact on the overall

weight of the cable harness. Several current air and space

platforms that use fiber optic systems include commercial and

military aircraft, unmanned aircraft, the International Space

Station and several NASA and international space exploration

systems. Substantial sources of variability may be introduced

in the fiber optic connectors and termini that are designed into

each piece of equipment unless the design specifications

adequately identify operating and storage environments, use

widely recognized standards for fiber optic cable assembly

manufacturing and testing. At each development and

manufacturing stage, from design through manufacturing,

each type of fiber optic connector and termini may require

unique fixtures for processing and inspection. Involving

personnel from design through installation, together with

suppliers, may help avoid significant costs for equipment and

minimize or eliminate costly defects. Fiber optic technologies

do not require significant power and complex electronics whileallowing signal processing to be located close to the networked

applications. There are many benefits of fiber optic systems for

air and space applications, including minimal electromagnetic

interference and environmental effects, lightweight and smaller

diameter cables, greater bandwidth and the ability to be easily

upgraded. This paper presents an overview of defining fiber

optic system and component performance by identifying

operating and storage environmental requirements, using

appropriate standards to be used in fiber optic cable assembly

manufacturing and inspection, interacting with component

manufacturers for interoperable hardware, developing

inspection methods and fixtures compliant with the selected

standards and developing a quality plan that assures

satisfaction of every design requirement.

 Keywords – Fiber Optics, Fiber Optic Connectors and Termini,

Bandwidth, Insertion and Return Loss, End Face Geometry

and Interferometry

I.  INTRODUCTION

urrent generation fiber optic technology is making

significant advances for use in a number of air and

space systems, including data transfer and communications,

fiber optic enabled sensors, electro-optical distributed

aperture systems and integrated diagnostics, prognostics,

and health management [1].

Cable strength, weight hardness and flexibility need to be

 balanced for each application Fiber optics offer minimal

electromagnetic interference (EMI), minimal

electromagnetic environmental effects (E3), lightweight

cables (compared to Cu), smaller diameter cables (compared

to Cu), greater bandwidth (compared to Cu), no grounding

or shorting concerns and upgradeable without replacing

cable harnesses. Fiber optic systems, due to its data rate

 performance, small size, and lightweight will continue to

 provide and revolutionize performance for many air and

space systems in the future.

II. HARSH EVIRONMENTS FOR FIBER OPTICS

There are many benefits of fiber-optic systems for air andspace applications, and for operation in harsh environments.

Cables used underwater may be exposed to corrosion,

moisture, high pressure, high forces in the axial and lateral

directions and low to high temperatures (-2°C to +36°C). An

armored cable jacket that will protect the fiber may be

required. Fiber optic cable assemblies used underground are

subject to high ambient and low temperature (-40°C to

+70°C), temperature cycling, high shock/impact, high

Ronald Pirich, Senior Member, IEEE , Northrop Grumman Aerospace Systems, Bethpage, NY 11714 

ron.pirich@ngc.com  and

John Mazurowski, Senior Member, IEEE ,

Pennsylvania State University Electro-Optics Center, Freeport PA 16229

C

Air   SpaceGround

UndergroundUnderwater

 

Figure 1. Environments for fiber optics.

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vibration, high pressure, exposure to hot or corrosive fluids

and exposure to hazardous gases, such as methane. On the

ground, fiber optic cable assemblies may have exposure to

dust, chemical and biological contaminants, vibration and

shock, temperature (e.g., icing), water/chemical emersion,

electromagnetic and radio frequency interference in a

temperature range of -90°C to +60°C. In aircraft

environments, temperature cycling over range of −54°C to

55°C (on aircraft) and -40°C to 85°C (in storage), vibration,shock, electromagnetic and radio frequency interference can

 be expected. In the space environment, temperature cycling

over a range of -200°C to +200°C, broad range of radiation

type and dose rate (protons, electrons, gamma, other forms

of radiation) is present.

II. FIBER OPTIC FAILURES

The selection of fiber optic cable assemblies and their

reliability is the most important consideration of the system

design and subsequent requirements [2]. Fiber optic cable

reliability is directly related to the frequency of cable

failures. Quantitative data should be collected and evaluatedto determine why and when failures occurred and to identify

design options which can be made to avoid these failure

conditions. An understanding of fiber-optic device failure

modes and mechanisms is critical to insuring unit reliability,

improving the manufacturing process, and allowing design

flexibility of the overall fiber-optic system.

Some common fiber optic cable assembly failure attributes,

as shown in Figure 2, include contaminated termini, poorly

 polished fiber connectors, excessive fiber apex offset,

 broken fibers, broken connector alignment sleeves, improper

choice of the fiber optic cable cladding and outer jacket and

inadequate termini cleaning after connector disconnect.

III. FIBER OPTIC CABLE ASSEMBLY

REQUIREMENTS AND STANDARDS

Optical performance requirements establish that systems

will perform correctly. A good fiber optic design includes a

link budget. Fiber optic hardware is designed with respect to

its environment. Components meant for different

environments may be physically incompatible. Guidance for

assembly and installation (including proper cleaning,

testing, tie downs and clamping) should be defined.

Cleanliness is of utmost importance for optical devices. Use

of proper cleaning methods does not reduce performance.

The system designer should establish consistent

requirements for fiber optic components consistent over all

suppliers.

Widely recognized standards are used to assure that

requirements are aligned with requirements, i.e., understood

and used by suppliers at all levels. Examples of some

commonly used government and commercial standards are

shown in Figures 3 and 4.

IV. FIBER OPTIC PROCESS MAP

It is important to determine and justify whether performance

against each requirement is guaranteed by design,

guaranteed by statistical process performance or guaranteed

 by test or inspection. The worst case scenario is that defects

are being produced and you cannot detect them.

Process validation ensures that a process consistently

 produces a product that meets its specifications. It is an

important component in the design, prototyping and

manufacturing process and one, if done correctly, that can

GovernmentPublications

MIL-PRF-29504Termini,FiberOpticConnector,Removable,GeneralSpecification

MIL-PRF-38999 Connector, Electrical, Circular, Miniature, High Density, QuickDisconnect,(Bayonet, Threaded, and Breech Coupling) Environment Resistant,RemovableCrimpandHermeticSolderContacts,GeneralSpecification

MIL-PRF-85045Cables,FiberOptics(Metric),PerformanceSpecification

MIL-PRF-49291Fiber,Optical(Metric),PerformanceSpecification

MILSTD130IdentificationMarkingofU.S.MilitaryProperty

MILSTD1678

NAVAIR01-1A-505-4 (T.O.1-1A-14-4, TM11500-323-23-4) InstallationandtestingPracticesforAircraftOpticCabling

 

Figure 3. Widely recognized government fiber opticcomponent and assembly standards [4].

Contaminated Termini

Poorly Polished Fiber

Connector 

Broken Fiber 

Excessive Apex Offset

Broken Alignment Sleeves

Inadequate Termini

Cleaning  

Figure 2. Attributes of fiber optic failures in

harsh environments [3].

CommercialRecognized Publications

- EIA/TIA-455-xxStandard Test Procedure for Fiber Optic Fibers,

Cables, Transducers, Sensor Connecting and Terminating Devices,and Other Fiber Optic Components

- ANSI/EIA/TIA-598 Optical Fiber Cable Color Coding

- IPC/WHMA-A-620Requirements & Acceptance for Cable & Wire

Harness Assemblies- IPC 8497-1 Cleaning Methods and Contamination Assessment forOptical Assembly

- IEEE STD 1202-2006 Standard for Flame- Propagation Testing ofWire and Cable

- UL 910Standard for Safety Test for Flame-Propagation and Smoke

Density-Values for Electrical and Optical Fiber Cables Used in

Spaces Transporting Environmental Air 

Figure 4. Widely recognized commercial fiber optic

component and assembly standards [4].

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save a considerable amount of time, money, rework and

resources. The key to a successful process validation is a

thorough understanding of the cable assembly

requirements, suitable production materials and

components, the manufacturing process, which includes

adhering to recognized standards, cable assembly and

measured test data (e.g., insertion and return loss,

temperature and structural durability either through test-to

failure or similarity with previous assemblies) and fiberoptic cable assembly installation (including proper cleaning,

testing, tie downs and clamping). An appropriate method to

understand the process is through process mapping [5].

A process map, as shown in Figure 5, is used to document

efficacy and to identify waste. Generally recognized metrics

for fiber optic infrastructure include physical attributes at

the cable assembly level including end face quality, such as

end face geometry, apex offset, radius of curvature and fiberheight, as well as optical performance for the cable

assembly such as insertion and return loss.

V. FIBER OPTIC CABLE ASSEMBLY TESTING

Testing of fiber optic cable assemblies has been

continuously improving over the last several years, as

shown in Figure 6.

Instruments include light meters, which qualitatively

measures light continuity in a fiber optic cable assembly.

Power meters measure the overall cable assembly insertion

and return loss. Optical Time Domain Reflectometry(OTDR) injects a series of optical pulses into the cable

assembly and measures the cable assembly’s length and

overall attenuation, including splice and mated-connector

losses. Optical Frequency Domain Reflectometery (OFDR)

uses a swept laser source and an interferometer to measure

the amplitude and phase response of reflected light as a

function of distance, with up to 10 micron spatial resolution

[6]. OFDR has the high sensitivity required to detect

Rayleigh backscatter (> 130 dB) and thus use standard

single mode fiber as the transducer. OFDR technology can

 be used to diagnose and troubleshoot the sensor fibers and

optical networks used for data transmission in both single

mode and multimode fiber. OFDR offers a significant

improvement in diagnostic capabilities when compared tousing a light source, power meter or OTDR. This is due to

the OFDR’s combination of high spatial resolution, high

sensitivity and zero dead-zone.

Endface geometry defines fiber optic terminus end face

 parameters radius of curvature, apex offset, and fiber height,

as seen in Figure 7. The development and implementation of

Figure 7. Geometry and optical path for end

face interferometer [7]. 

Light MeterPower Meter

OTDR

OFDR

End Face Interferometry

Insertion and Return Loss

 

Figure 6. Fiber optic cable assembly performance testing.

Cable

Installation

Measured and

Observed Data

Approvals and Sign

Offs

Locations where

Components & Cable

Assembly are Stored

Cable

Components

Cable

Assembly

Production

Materials

Recognized and Draft

Standards

Cable Assembly

Requirements

 

Figure 5. Fiber optic process map.

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interferometry for end face geometry inspection allows the

 precise measurements fiber radius of curvature, apex offset

and fiber height as well as the return loss associated with the

fiber optic assembly.

VII. SUMMARY

The key to a successful process validation for fiber optic

cable assemblies is a thorough understanding of cableassembly requirements, suitable production materials and

components, the manufacturing process, which includes

adhering to recognized standards, cable assembly and

measured test data (e.g., insertion and return loss,

temperature and structural durability either through test-to

failure or similarity with previous assemblies) and fiber

optic cable assembly installation (including proper cleaning,

testing, tie downs and clamping) [8].

An important tool to understand the process is through

 process mapping. Process validation ensures that a process

consistently produces a product that meets its specifications

It is an important component in the design, prototyping andmanufacturing process and one, if done correctly, that can

save a considerable amount of time, money, rework and

resources

REFERENCES

[1]  R.G. Pirich and P. Anumolu, “Next-Generation Fiber-Optic

Technology Enablers for Manned & Unmanned ISR Platforms,” 2008IEEE Avionics Fiber-Optics and Photonics Conference, pp. 3-4, 2008.

[2]  C. Volk, J. Lincoln and D. Tazartes, “Northrop Grumman's Family of

Fiberoptic based Inertial Navigation Systems,” Position, Location,And Navigation Symposium, 2006 IEEE/ION, 2006.

[3]  R.G. Pirich, “Fiber optics for Use in Air and Space Harsh

Environments,” 2011 IEEE Avionics Fiber-Optics and PhotonicsConference, pp. 3-4, 2011.

[4]  R.G. Pirich and K. D’Ambrosio, “Systems, Applications and

Technology Conference (LISAT), 2011 IEEE Long Island,” pp. 1-4,2011.

[5]  R.G. Pirich and J. Mazurowski, “Concurrent Engineering In Fiber

Optic Infrastructure,” 2011 Defense Manufacturing Conference,2011.

[6]  P. Toste, “Optical Backscatter Reflectometer™ Benchtop”, Luna

Technologies, Inc., 2010.

[7]  After “Aerospace Standard 5675 Characterization and Requirements

for New Aerospace Fiber Optic Cable Assemblies”, February 6, 2011.

[8]  MIL-STD-1678/5, Department Of Defense Standard Practice: FiberOptic Cabling Systems Requirements And Measurements (Part 5:

Design Phase And Legacy Measurements) 28 May 2010.

Ronald Pirich  is a Northrop Grumman Technical Fellow responsible for

electromagnetic environmental effects (E3), chemical, biological, nuclear,radiological and explosives (CBNRE) warfare

defense and advanced coatings at Northrop

Grumman’s Aerospace Systems Advanced Programs& Technology / Technology Development Center.

His current efforts include advanced fiber optics, E3

modeling, multi-mission sensor integration,threat/vulnerability/risk assessment, development of

advanced coatings for air and space applications and

 point and standoff sensors for the detection andclassification of various CBNRE threats and

associated wireless communications, modeling and simulation. Dr. Pirich

received his BS in Physics/Mathematics, MS and PhD in Physics from theState University of New York and a Post-Doctoral Research Fellowship

from the University of Cincinnati.

John Mazurowski  is a Senior Research Engineer in the Fiber Optics,

Photonics, and Engineering Division of the the Penn State Electro-Optics

Center. John has also worked in several engineering positions, previously in the Corning Photonics

Division in support of assemblies manufacturing,

advanced manufacturing engineering, andcomponents, was a member of the technical staff at

Biocontrol Technology, where he supervised the

design and transition of multi-channel cooled photodetector arrays for medical applications in spectroscopy and was a

member of the engineering staff at the General Electric ElectronicsLaboratory where he worked on assignments in millimeter wave device and

circuit characterization, materials characterization, and MBE crystal growth

of III-V heterostructures for HEMT, PHEMT, HBT, and optical devices.