In the past two decades, the field of information transmission has revolutionized technologically. Currently, the preferred mode for commercial long distance telecommunication is fiber optics. Enabled by the solid state laser and the production of low cost optical fibers with reasonably low attenuation, this revolution is expanding a variety of related areas viz. sensors and computing. This paper gives an insight to the military implications of the fiber optics technology.

1. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
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DETAILED ANALYSIS OF FIBER OPTIC NETWORKS
AND ITS BENEFITS IN DEFENSE APPLICATIONS
Himanshu K. Patel1
, Shalin S. Shah2
1,2
Nirma Institute of Technology, Ahmedabad - 382 481
ABSTRACT
In the past two decades, the field of information transmission has revolutionized
technologically. Currently, the preferred mode for commercial long distance telecommunication is
fiber optics. Enabled by the solid state laser and the production of low cost optical fibers with
reasonably low attenuation, this revolution is expanding a variety of related areas viz. sensors and
computing. This paper gives an insight to the military implications of the fiber optics technology.
I. INTRODUCTION
Until the late 1970s, telecommunications systems depended on the advances in electronics to
provide improved performances at a lower cost. As the fiber optics technology emerges, soon
communication links set up using copper cables will be obsolete. Owing to the advantages fiber optic
networks have over copper cable networks, it has already replaced them in many applications,
including telephony, computing, media, communication, medical applications, instrumentation, and
gradually proceeding towards the military aspect. Systems Planning and Analysis, Inc., under
sponsorship from the United States Navy, Office of Naval Research (ONR), has developed a
structural health monitoring system for large-scale structures, based on fiber Bragg grating (FBG)
sensors.[1]
A brief comparison between the fiber optic and copper cable has been shown in Table 1.
II. MILITARY APPLICATIONS
Commercially, fiber optics technology has been a tremendous hit but on the contrary, the
military applications have not been fully exploited as yet. With the recent advancement in the fiber
optics tech, the military can benefit substantially from this technology with less investment.
For secure communications, high bandwidth applications and large step-out distances fiber
optic technology is superior to electrical data transfer.[2, 13, 14]
The higher end characteristics of the
optical fibers make them even more desirable for military applications. These attributes include
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immunity to electromagnetic interference, relative security from eavesdropping, the ability to span
long distances without repeaters, and low cable weight.[3]
But additional requirements like wider
operating and storage temperatures, and the ability to withstand severe vibration, shock and other
mechanical stress has imposed restrictions on the use of fiber optics and hence limited their viability.
Also, the lack of readily available hand tools, parts, training, etc for installation, maintenance and
repair of systems in the field acts a big hindrance. But this scenario is fast changing due to the
proliferation of a variety of commercial systems. By and large, the technologies which need
improvisation are simply more rugged prototypes of the commercially available technologies with
increased tolerance on the physical aspect.[4]
Table 1
Characteristics Fiber Optic Copper Cable
Weight Low Heavy
Dimensions Small Moderate
Attenuation (Loss) Low Moderate
Range Big Small to Medium
Data Rate High over long Limited for long
distances distances
Electro-magnetic None Yes
Sensitivity
Cross Talk None Critical
Potential Not necessary Necessary
Equalization
Lightning Protection Not necessary Necessary
EMP Damage None Big
Electro-Optical Necessary Not necessary
Conversion
Security in Explosion Yes No
Endangered
Environment
Installation/Handling Minimum Bend RadiiNo crushing
The most promising applications of this technology in the defense sector are in weapons
systems, sensors, surveillance systems, optical computing systems and information transmission
aboard vehicles Fiber Optic Guided Missile (FOG-M) is a weapon system currently being developed
and researched rigorously[10]
. This is a medium range, lock-on-after-launch weapon system to be
used against helicopter and other ground vehicles. A similar fiber optic guided missile system is also
under development for the Navy. Fiber optics can be used extensively for a variety if sensing and
surveillance applications due to their rugged characteristics and the ability to monitor a panorama of
physical parameters. For example, underwater submarine surveillance can be improved as a result of
the high sensitivity obtained using an acoustic inferometer made from optic fiber. Moreover,
replacement and maintenance costs can be substantially reduced if one used the sensors owing to
their extremely rugged structures.

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Fiber optics used in neural networks is a leading technology which is on the mind of every
major defense contractor. Though it is still in the research stage, many applications have already
been identified, including target recognition, sonar classification and target tracking. The weapons
systems will be revolutionized if the task of designing a neural network can be accomplished.
Such inherent advantages of fiber-optics make them an integral part of military vehicles.
Ground, sea, and air vehicles can all benefit if this technology is implemented in the foreseeable
future. Also owing to the reduced weight of fibers as compared to copper cables and their immunity
to electromagnetic interference, they are being considered for aircraft design too.[5]
The trends in fiber-optic devices are towards low-loss fibers with greater resistance to
damage, semiconductor lasers with low dispersion and greater tenability, and a variety of optical
control devices with high speed and which integrate well with electronics.[13,14]
This does no harm to
its military applications. The military shall only benefit as such developments continue. Military
applications of fiber optics have been displayed in Table 2.
III. COMMUNICATIONS
From the security perspective, the use of for military communications is unparalleled.
Because no electro-magnetic fields are produced, eavesdropping is impossible. Hence it provides
unparalleled use for all types of communications. The Intrusion Detection Optical Communications
(IDOC) system is being built for the Air Force by Hughes Microelectronics Systems Division to link
two computer systems or local area networks. This system has recorded a transmission rate of up to
12megabits/sec, over distances up to 1.5km. This system will automatically shut down if the signal is
disrupted. Researchers at the Rome Air Development Center (RADC) at Hanscom Air Force Base
are working to increase the system’s capabilities to 100megabits/sec over a distance of 35km.
A version of this system can be employed if fiber optic connectors could be made that are
easy to install and uninstall. A fiber optic communications network could be installed and the units
could be installed in the field could establish a secure communications link to the network by simply
“plugging in”.
Fiber optics could also be employed in the military to establish a temporary short-range
communication link.[6]
Table 2
Application Category System Benefits of Fiber
Communications Intrusion Detection Allows non-encrypted
Optical system
Communications Improved security
(IDOC) System
Weapons FOG-M High data rate
AAWS-M EMI/RFI immunity
FOG-S Reduced vulnerability
PDAMS of launcher
Sensors - Nuclear High pressure sensor Ability ti sense in
Testing particle generation
phase
Ranges in excess of 10
kbar
Accurate tracking of
impulses

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Image probes Combustor flame Compactness and
probes Reliability
Withstands high
temperatures
Surveillance Ariadne Program High sensitivity
Submarine Can hold up in
corrosive sea
environment
UAV R&D stage Covert Operation
Airborne Platform Fly-by-light system Weight/space savings
Avionics
Radar Phased array Capability to exploit
parallelism of array
Aircraft stress R&D Stage Light weight
monitoring Small size
Real time monitoring
Optical Computing Neural Networks Massive parallelism
Shipboard Information system Weight/space savings
Damage control system Low cost
(in tandem with sensor EMI/RFI immunity
network) Ability to hold up in
corrosive sea
environment
High data rate
No spark hazard
Ability to service line
cable
Navigation Fiber Optic Gyroscope Small size
(FOG) Light weight
Low power
Ruggedness
Potentially modest cost
Potentially great
accuracy

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IV. WEAPON SYSTEMS
The only fiber optic weapon that is currently being developed is the FOG-M. The FOG-M is
a medium range (~20-40 km), lock-on-after-launch weapon system to be used against helicopters and
ground vehicles. FOG-S, another fiber optic guided weapon, is also being proposed for the Navy. A
fiber guided weapon for the AAWS-M (Advanced Anti-armor Weapon System-Medium) , which is a
short range man portable weapon, has also been proposed. It is supposed to be used primarily against
tanks.[7]
Both the FOG-M/S and the AAWS-M concepts are hit-to-kill weapons and use a man in the
loop for guidance. A camera has been installed in the nose of the missile which sends back a picture
to the gunner during its flight. This is done with the help of a fiber optic cable paid out from the
missile during flight. Also, through the fiber link, guidance commands are transmitted from the
gunner’s position to the missile. A single-mode fiber with a silica core is doped with germanium or
phosphorus, a pure silica cladding, and an ultraviolet clear polymer coating to protect the fiber from
damage, are typically used. The outside diameter of the fiber is 200-250 microns.
This weapon is made possible only by the fiber data link. Copper cables are rendered useless
in this case because high bandwidth is required to transmit a picture which is unavailable when
copper cables are used. For a fiber optic guided weapon to function, the fiber is supposed to pay out
at missile velocities without breaking. Fiber pay out speeds up to 600 ft/sec have been successfully
demonstrated in tests. The maximum theoretical pay out speed is approximately 2,600 ft/sec.
The Air Force and the Navy are also considering a fiber guided weapon to be dispensed from
an aircraft. A possible tactical application of fiber optics technology is to use aircraft to drop buoys
into the ocean with fiber optic guided missiles. The buoys would have either a fiber optic or radio
link to the aircraft or a radio link to the ship or land base. When any enemy ship or plane moves into
their range, these missiles can be launched. This technique can be used to deny both aircraft and
ships to a fairly large section of ocean.
V. SURVEILLANCE/SENSORS
Owing to their rugged characteristics and ability to monitor a wide range of physical
parameters, fiber optic sensors offer great promise in a variety of future sensing and surveillance
applications. Table 3 lists the currently measured performance parameters for some fiber optic
sensors.
The use of fiber optics technology in battlefield surveillance has many possibilities. Since
fiber optic sensors are compact, rugged, and extremely sensitive to a variety of parameter, they are
used in the battlefield environment[12]
. For example, a pressure sensor buried in a road or a seismic
sensor along the road could determine the number of vehicles that pass a point or it can also help in
recognizing the type of vehicle based on the pressure readings. Moreover, underwater submarine
surveillance could be improved by using optical fiber to make an acoustic inferometer. Also, the
maintenance and replacement costs due to the corrosive sea environment will be reasonably reduced
due to the rugged nature of these sensors. Fiber sensors can also be used to monitor a number of
engine parameters including temperature, pressure, engine speed, and so on during the flight.
Another possible use of fiber optics for surveillance is unmanned air vehicles (UAVs) with a
fiber optic data link between the vehicle and a ground station. One can then transmit guidance
information to the vehicle and images from the vehicle to the ground station via the data link. The
primary advantages of using a fiber optic link are immunity to jamming and EMI and covert
operations.

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Table 3
Parameter of Interest Measured Performance
Hydrophone 20 dB – 1 micropascal
(pressure)
Pressure 0-300 mm Hg
Magnetic field 10-9
Gauss, 1mW optical power
Gyroscope 10-3
/h, 1mw optical power
(rotation)
Position 10-3
in. resolution
(displacement)
Vibration 10-6
-10 g
(acceleration)
Flow 10-6
-10-5
m/s
Liquid level 0.5 mm
Oil Pollution Monitor 15 ppm
Temperature 0-100 degrees
pH 6.8-7.4
VI. OPTICAL COMPUTING
As optics become a major networking media in all communications needs, optical
interconnects will inevitably play an important role in interconnecting processors in parallel and
distributed computing systems.[8]
Several Government institutions and Defense Academies are
working on optical computing. Efforts are under way to produce a device that can automatically
recognize a target using optical signal processing. In this system, only phase information would be
used to recognize the target in real time.[9]
Neural Networks is an application of the fiber optics technology in the field of optical
computing. A lot of research work is being carried out in this are because of its unparalleled
parallelism. The manmade neural networks are composed of a variable resistor and a feedback loop
to change the resistance depending on the output. Many applications of the neural networks are:
• Target recognition
• Word recognition
• Sonar classification
• Target tracking
• Robotics
Examples of military tasks where neural networks can be employed are:
• Detection of relocatable strategic weapons and recognition of ground features by means of
satellite sensors.
• Stealth aircraft detection by infrared search-and-track systems.
VII. FIBER OPTICS ABOARD VEHICLES
Fiber optics is well suited for use aboard military vehicles because of its inherent advantages.
Currently, a lot of emphasis has been given to making the aircraft or ship lighter. As compared to the
copper cables, fiber optics are lighter and hence better suited. Also, the fibers are immune to EMI

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and lightning strikes, making electrical shielding unnecessary. Optical fiber networks can prove to be
a very important factor in phased array radar system. It can also revolutionize the navigation market
when Fiber Optic Gyroscopes (FOGs) become available in the market[11]
. Also, fiber signal paths are
very well suited for use on shipboards. This is because extreme EMI levels, electrical problems,
flooding, and corrosive environment make fiber a natural choice for data transfer aboard ships.
VIII. ACRONYMS
AAWS-M Advanced Anti-armor Weapon System - Medium
EMI Electromagnetic Interference
EMP Electromagnetic Pulses
FOG Fiber Optic Gyroscope
FOG-M Fiber Optic Guided Missile
FOG-S Fiber Optic Guided Skipper
HMMWVHigh Mobility Multipurpose Wheeled Vehicle
IDOC Intrusion Detection Optical Communications
MLRS Multiple Launch Rocket System
RADC Rome Air Development Center
RFI Radio Frequency Interference
TBM Tactical Ballistic Missile
UAV Unmanned Aerial Vehicle
IX. REFERENCES
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monitoring system: rough sea trials testing of the RV Triton”, OCEANS '02 MTS/IEEE,
Vol3. Pg. 1806-1813
2. Jones, R.T.; Thiraviam, A., “Reliability of Fiber Optic connectors”, OCEANS 2010, Seattle,
Dec.2010
3. “A Rand Note N-2866-RC Military Applications of Fiber Optics Technology”, Joseph F.
Benzoni, David T. Orletsky.
4. “A Lot of Fiber Optics’ Likely to Fly on NASP”, M. W.Matthews (ed.) Military Fiber Optics
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5. Pandhi, Sushil N., “The Universal Data Connection”, IEEE Spectrum.
6. Sherrets, Larry, Lightguide Digest, Vol. 1
7. Mondrick, Alexander, and James Wright, “Fiber Optic Communication Systems for the U.S.
Army”.
8. Yuanyuan Yang; Jianchao Wang, “Sparse WDM optical interconnects under wavelength-
based model”, OCEANS '02 MTS/IEEE, Vol3. Pg. 1806-1813
9. “Researchers Foresee Sharp Increase in Military Photonics Applications:, Donald Fink (ed.),
Aviation Week and Space Technology.
10. Tang Lin Ming Hai (Phisical Department, University of Science and Technology of China
Hefei 230026);A Survey of Applications of Optoelectronic Technology in Modern
war[J];OPTOELECTRONIC TECHNOLOGY & INFORMOTION;1999-05
11. S. E. Webster, A. D. Bowen, Woods Hole Oceanographic Institution ; Feasibility Analysis of
an 11,000 m Vehicle with a Fiber Optic Microcable Link to the Surface;IEEE Explore.
12. K. T. V. Grattan and B. T. Meggitt, eds., Optical Fibre Sensor Technology II;Devices and
Technology, Chapman and Hall, London, 1998.

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13. Patel H. K., “Hollow Waveguides - significant class of infrared fiber optics”, Proeedings of
National Conference on Emerging Trends in Instrumentation Systems, January, 2006.
14. Patel H. K., Desai M. D., “Infrared Fiber Optics: A Qualitative Comparison”, Proceedings of
National Conference on Sensors (NCS’05), 2005.
15. Bhumit P. Patel and Rohit B. Patel, “Comparison of Different Modulation Formats For 8
Channel Wdm Optical Network At 40 Gbps Datarate With Non-Linearity” International
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2014, pp. 37 - 51, ISSN Print: 0976-6480, ISSN Online: 0976-6499.
16. Elham Jasim Mohammad and Gaillan H. Abdullah, “Soliton Optical Fibers Supercontinuum
Generation Near The Zero Dispersion” International Journal of Industrial Engineering
Research and Development (IJIERD), Volume 4, Issue 1, 2013, pp. 52 - 58, ISSN Online:
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