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An approach to the estimation of life cycle costs of a fiber-optic application in military aircraft
McGrath, John Michael; Michna, Kenneth Ralph
Monterey, California. Naval Postgraduate School http://ndl.handle.net/10945/20761
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= > ma i> ow m 3 ' () “U ~ — oO a) a a
John Michael McGrath
NAVAL POSTGRADUATE SCHOO
Monterey, Galifornia
THESIS
AN APPROACH TO THE ESTIMATION OF Piste CrChE COSTs OCF°A FIBER-OPTIC APPLICATION IN MILITARY AIRCRAFT
by
John Michael McGrath Kenneth Ralph Michna
September 1975 Thesis Advisor: Catia eee oles
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An Approach to the Estimation of Life Cycle Costs of a Fiber-Optic Applicatio
in Military Aircraft AU THOR(e) John Michael McGrath Kenneth Ralph Michna
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Master's Thesis; September 1975
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Naval Postgraduate School Monterey, California 93940
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. KEY WORDS (Continue on reveree eide if neceeeary and identity by biock number) Optical fibers, fiber optics, optical waveguides, light emitting diodes, PIN diodes, economic analysis, cost
effectiveness analysis, life cycle cost model
. ABSTRACT (Continue on reveree cide if neceseary end identity by biock number) As significant technological advances in fiber optics and
optical data transmission methods are being made, it is necessary to develop appropriate methods for estimating life cycle costs for alternative coaxial/twisted pair wire and optical fiber avionics. Measures of effectiveness are suggested for each alternative system. An approach, which
structures the technological and demand uncertainties of
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fiber optics, is developed through scenarios as a means of relating cost and effectiveness. It is suggested that Delphi and experience curve techniques be used in conjunction with ordered scenarios as a technological forecasting technique
for estimation of life cycle costs of fiber optics. In addition a review of the historical and technological background of fiber optics and their application to the Naval Electronics Laboratory Center (NELC) A-7 Airborne Light Optical Fiber Technology (ALOFT) Program is included.
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An Approach to the Estimation of Life Cycle Costs of a Fiber-Optic Application in Military Aircraft
by
John Michael McGrath Lieutenant Commander, United States Navy B.S., United States Naval Academy, 1962
Submitted in partial fulfillment of the requirements for the degree of
MASTER OF SCIENCE IN MANAGEMENT and
Kenneth Ralph Michna Lieutenant Commander, United States Navy A.B., Wabash College, 1965
Submitted in partial fulfillment of the requirements for the degree of
MASTER OF SCIENCE IN OPERATIONS’ RESEARCH from the
NAVAL POSTGRADUATE SCHOOL September 1975
E SCHOOL Y. CALIFC iA 93940
ABSTRACT
As significant technological advances in fiber optics and optical data transmission methods are being made, it is necessary to develop appropriate methods for estimating life cycle costs for alternative coaxial/twisted pair wire and optical fiber avionics. Measures of effectiveness are suggested for each alternative system. An approach, which structures the technological and demand uncertainties of fiber optics, is developed through scenarios as a means of relating cost and effectiveness. It is suggested that Delphi and experience curve techniques be used in conjunction with ordered scenarios as a technological forecasting technique for estimation of life cycle costs of fiber optics. In addition, a review of the historical and technological background of fiber optics and their application to the Naval Electronics Laboratory Center (NELC) A-7 Airborne Light Optical Fiber
Technology (ALOFT) Program is included.
TABLE OF CONTENTS
I. INTRODUCTION -------------------------------------
II. BACKGROUND ---------------------------------------
A.
HISTORICAL BACKGROUND ------------------------ 1. Background of Glass Fibers/Fiber Optics --
2. Background of NELC ALOFT Demonstration Program --------------- 2 eo
3. NELC A-7 ALOFT Demonstration Approach ----
4. A-7 ALOFT Demonstration Management Organizational Structure -----------------
III. FIBER-OPTIC TECHNOLOGY AND ITS APPLICATION
Po OR a eee A. GENERAL -------------- 2222-22222 eee ee ee B. FIBER OPTICS RELATED TECHNOLOGY --------------
i eteee iatten == ———-—----=—-=----------—----===- Peat asc —=—————— = — = — — 3. Multiplexing/Data Bug ------2-2--2--------
DESCRIPTION OF THE BASIC COMPONENTS OF A FIBER-OPTIC DATA TRANSFER SYSTEM -------------
1. General ---------------------------------- 2. Glass Fiber/Cables ----------------------- 3. Connectors/Couplers a = See = = elie
a. Connectors ------co- nooo ooo ooo ome oon
Boeecouprers for Data Bus Application --=-
igi EO 16
16
24
28
30
34
35 35 37
40
44 44 45 DZ DZ
58
De
4. Light Sources/Signal Drivers ------------- a. Light Emitting Diodes (LEDs) --------- b. Semiconductor Lasers ----------------- >. Signal Receivers/Detectors ---------------
SYSTEM DESCRIPTION OF FIBER OPTICS AS EMPLOYED IN THE A-7 ALOFT DEMONSTRATION ---------------
1. System Description -----------------------
IV. AN APPROACH FOR A COST-EFFECTIVENESS STUDY OF AVIONICS BATA LINK ALTERNATIVES ------------------
A.
ley
GENBRAD -------—-------~-~---~~--~-----=-------- MEASURES/LEVELS OF EFFECTIVENESS ------------- SOST AMAA AS “66283 reer 1. Life Cycle Costing ----------------------- 2. Cost Data Collection Effort -------------- COMBINING COST AND EFFECTIVENESS -------------
l. Ordering Uncertainties Through Scenarios -
a. scenario I -- A Neutral Context ------ b. Scenario II -- A Modestly Optimistic CE O@SR 2S SoS ons 5555S] Sse aS eee
c. Scenario III -- A Modestly Pessimistic Context ------------------
2. Constructing Cost-Effectiveness Curves from Scenarios ---------------+ ecco
Pe VOmGoOctinG EECHNIOURS FOR FIBER OPTICS ----------—
A.
Dee
GENERAL -------------------- o-oo ee eee
aN apa CHNMOUR el ===-os2— aoe eee
a0
DY,
62
65
85
C. THE EXPERIENCE CURVE TECHNIQUE --------------- iy
VI. SUMMARY AND CONCLUSIONS See ee ea 134 APPENDIX A, A-/ Navigation Weapons Delivery System
(NWDS) Schematics -------------------------- WSs
APPENDIX B, A-/7 ALOFT Component Requirements ----------- 140
APPENDIX C, A-/7 ALOFT Component Descriptions ----------- 144
~oenwixX D, Faber Optics Cost Data Collection ---------- 148
APPENDIX E, Industry Contacts for Fiber-Optic Convenes. 2 = aioe ios SaaS 153
APPENDIX F, Assumptions for an Economic Analysis of
eu: NONI SIE) C3 aaa ll LSy OE LTO PLD aaa ILS, ie omen LON (oie = >= ---<-- ss Sse sso ce a= - == === 162
Figure II-1l
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Prt -2 PEL -3 ee —4 ILI III -6 ek / III -8 eit —9 II1I-10 JUEIL Salk eh 2
met — 13
LIST OF FIGURES
Page Historical progress in low-loss seyeebdas: lowest attenuation achieved vs. year --------- IN A-7 ALOFT Demonstration milestones ---------- 29 A-7 ALOFT Economic analysis activity flow ---- 3] A-7 ALOFT Project Office organization Structure rrr r ee em re ren rer reece eer enrnren- 52 A-7 ALOFT economic analysis organization SEXYUCTULE --——— enn He mm nn nm men wn nn nw ww nn nen 38 Attenuation as a function of wavelength in a recent Corning low-loss optical fiber ------ 37 pe Iieemiadce cysoeeis. -——-—-—9-——-——————————— 39 Data multiplexing <<<<9--<-<<3-c<-<<<-e--------- 41 ivoeeweaireCrare data busvarchitecture =-----~- 43 ip ee lascee LAadehiber: —---=-—-——-—--——=————-=— 46 Large-core, solid-clad fiber ----------------- 47 eee Oden i Deis ae = ee a 47 Graded-index fiber -------------99------------ 48 Fiber-optic bundle ------------9e rrr nner 50 iitelnogcmea lCmCONMCC EONS (= =—-——==—-————— 53 i peroal ier optic slink Leplacement=—-----—-- 56 Stamdaca package = fiber-optic module ----=-<- 56 Pao MmeCmImmmOaehesmeOnInterlaACeS (=a ———sa—— > — 14 —> ye)
Figure III-14
HiL-15
ny = 1
iy 2
Laser injection diode bonded to fibers ------- Optical circuit on a chip as envisioned
by Texas Instruments ------------------------- Economic analysis process --------------------
Hypothetical cost-effectiveness curves displaying dominance -------------------------
Hypothetical cost-effectiveness curves ------- Measures of effectiveness -------------------- Life cycle cost elements --------------------- Rupr OpEtecscable demand, by Scenarios: =---=-= Scenario/effectiveness/time matrices ---------
Scenario related cost-effectiveness curves ---
Sample Delphi questionnaire ------------------
The 80% experience curve on an arithmetic grid -------------------------------------- =e
The 80% experience curve on a logarithmetic grid -------------------------- oo en renner ee
itm@ecrated Cilrcules ExperlLence curve =====-=<-> Pomwiny lenlortde experience curve ---=-=----—- MECWeameacteri Stile Stable pattern -=--—=—-=—---—-— A typically unstable pattem -----------------
A characteristic unstable pattern after it has become stable ----------------------------
Hypothetical example of a fiber-optic cable experience curve --------cr rere oe
70
ree: Te 76 79 102 104
105
de
ACKNOWLEDGEMENT
The authors wish to express their appreciation to Associate Professor Carl R. Jones for his encouragement and assistance in this work.
The authors also wish to express their appreciation to LCDR J. R. Ellis, Mr. Roger Greenwell, and other personnel of NELC who unselfishly shared their time and materials to
mesist in this work.
10
I. INTRODUCTION
Present day avionics in military aircraft utilize twisted shielded pair wire and/or coaxial cable to transfer signal data. These data link subsystems reflect post-World War II state of the art in electronic development. Electronic signal transmission by this means exposes avionics to potential operational degradation and damage because of the suscepti- bility of metallic conductors to electromagnetic interference, radio-frequency interference, and nuclear-generated electro- magnetic pulse. Other sources of electronic interference such as cross-talk, ground looping, reflection, and short-circuit loading also degrade system operation.
A recent technological breakthrough in the field of fiber optics has made fiber-optic data link applications technically feasible, and perhaps desirable, for use in military aircraft avionics systems. Fiber optics technology does offer several significant advantages for avionics data link subsystems. The primary advantages are that it: (1) is not susceptible to electromagnetic interference (EMI) nor to electromagnetic pulse (EMP) associated with a nuclear blast; (2) does not generate EMI; (3) is isolated from ground plane signals; and
(4) is capable of higher data rate transmission.
Et
As a result of feasibility tests and demonstrations conducted or sponsored by Naval Electronics Laboratory Center (NELC), San Diego, approval was gained from the Assistant Secretary of the Navy for Research and Development to implement a two-year feasibility program to install fiber optics com- ponents (fiber-optic cables, light sources, light detectors, and connectors) in place of standard twisted pair wire and coaxial cable for selected components of the Navigation/
Weapons Delivery System (N/WDS) of an operational A-7E Corsair IL light jet attack aircraft. The program, called the A-7 Airborne Light Optical Fiber Technology (ALOFT) Demonstration, is a feasibility demonstration to determine the information transfer capability of an aircraft avionics system through point-to-point applications of fiber optics.
Concurrent with the A-/7 ALOFT Demonstration checkout, test and evaluation, an economic analysis was desired by NELC for the two alternative systems; coaxial cabling and fiber-optic cabling. These two alternatives, together with their associated components, will hereafter be referred to as "coax" and "fiber Spetcs.
The basic format of an economic analysis involves the deter- mination of the cost and effectiveness of competing alternatives. A life cycle cost model, as defined by NELC and Naval Postgrad- uate School (NPS) students is used as the costing basis for the
Ivo alternatives. 12
A contractor will perform the costing of the coax alterna- tive. He will also determine the measures of effectiveness for both the coax and fiber optics systems. Naval Postgraduate School students will perform the costing effort of the fiber optics alternative. The authors of this thesis perform a preliminary costing effort for the fiber optics alternative by developing an approach to costing fiber optics as an emerging technology. NPS students and NELC systems analysts personnel will coordinate future efforts toward the desired objective of numerical estimation of fiber optics life cycle costs.
As a baseline thesis for follow-on NPS theses students, the authors have discussed the historical and technological background of fiber optics as well as the background of the A-7 ALOFT Demonstration. A general discussion of a cost- effectiveness analysis is presented together with possible measures of effectiveness (MOEs) for data transfer.
Since fiber optics cost data is either non-existent or available only on a prototype basis, the authors' basic approach to costing fiber optics is done through scenarios. Scenarios offer a means of ordering the uncertainties of an emerging technology. They define the possible futures of the fiber optics industry and its related technology. Three sample scenarios developed by the authors provide specific time-
related estimates as to civilian/military demand, growth rates,
Ls
standardization and technological development. These repre- sentative scenarios are meant to provide the basis from which cost estimates could be made.
Two exploratory techniques, Delphi and experience curves, are discussed as they pertain to the costing of an emerging fiber-optic technology. A sample Delphi questionnaire is developed as a means of soliciting forecasts from a panel of experts in order to deal with specific uncertainties associated with fiber optics. (e.g. When will production bases be established for fiber optics components?) The information gained from the Delphi survey can be used to refine the estimates contained in the scenarios as well as minimize the number of possible scenarios.
Experience curve evidence is discussed as a means for fore- casting unit cost reduction as the fiber optics experience base accumulates. The information required for using experience curves is provided by the scenarios. Experience curves can then be used as a means of predicting the cost behavior of components relating to fiber-optic technology.
It is felt by the authors that these techniques; scenario- writing, Delphi and experience curves, can be combined as a cost-predictive method to estimate component prices of an emerging technology such as fiber optics. These techniques
can then provide a means of estimating costs for the life cycle
14
cost model elements used in a cost-effectiveness study. Not only will the fiber-optic component procurement costs be estimated, but the costs to operate and maintain a fiber-optic system will also be determined through future efforts.
This thesis, then, is the first step in developing a cost- effectiveness study which could aid in making decisions concerning the use of coax or fiber optics in the next series of military aircraft to be designed and built (VAX, VFX, VPX, etc.).
It is the basic conclusion of the authors that the emerging fiber-optic technology deserves full and continuing effort and attention by research and development (R&D) agencies. Even if the results of initial cost-effectiveness studies are such that the decision is made to not use fiber optics in the next generation of aircraft, the authors feel that it would be a mistake to cut back or reduce fiber optics R&D funding. The military services are pursuing extremely meaningful and productive research and development in a field containing great potential for future benefits to the military services in general. It is expected that fiber optics will be used in some future generation of military aircraft and weapons systems. These future weapons systems would be the beneficiaries of
today's efforts from the development of this emerging technology.
15
II. BACKGROUND
A. HISTORICAL BACKGROUND 1. Background of Glass Fibers/Fiber Optics
Glass has been used in a multitude of applications from very early times. The earliest glass objects come from Egypt and are dated from circa 2500 B.C. The first vessels of glass were manufactured in Egypt under the 18th dynasty, particularly from the reign of Amenhotep II (1448-20 B.C.) onward. The possibility of drawing hot glass into threads was recognized in the Rhineland during the late Roman empire as well as in ancient Egypt and such threads were wound around vessels as a decoration.
In the 18th century, fine threads were prepared from a heat softened glass rod by using a "spinning wheel" process. The next development was a mechanized drawing process by attaching the fiber from the heat-softened rod to the surface of a large revolving drum. In 1908, G. von Pazsiczky replaced the rods with a refractory glass-melting chamber that had a series of holes in the bottom to provide drawing points. A different method of production was developed in 1929 whereby the application of centrifical force forced the glass through
radial serrations resulting in a tangled mass of fibers. /16/
16
It is entirely possible that early Egyptian and Grecian Glassblowers observed the phenomenon of multiple total internal reflections in conducting light along transparent glass cylinders, and in fact, there are a number of unsubstantiated historical claims. However, the earliest recorded scientific demonstration of the phenomenon of total internal reflection was recorded by John Tyndall at the Royal Society in England in 1870. In his demonstration, he used an illuminated vessel of water to show that when a stream of water was allowed to flow through a hole in the side of the vessel, light was conducted along the curved path of the stream. D. Hondros and P. Debye followed the work of Tyndall by doing some theoretical studies on optical wave propagation in fibers in 1910, but little else was done in the way of experimentation.
The phenomenon described by Tyndall was disregarded and lay dormant until 1927, when J.L. Baird in England and C.W. Hansell in the United States considered the possibility of using uncoated fibers in the field of television to transmit and scan an image. They were followed closely by H. Lamm of Germany who used a crude assembly of quartz fibers to demon- strate the basic image and light transmission properties of fibers. Activity in this area then all but ceased for two
decades. [25/
17
Quite unrelated to previous experiments with glass fibers as light conductors, manufacturing methods for producing glass fibers were being perfected. For example, in 1938 the Owens-Illinois Glass Company joined with the Corning Glass Works to form a new independent glass fiber firm. The company, the Owens-Corning Fiberglass Corporation, developed large- scale production methods to produce glass fibers. The spun glass method allowed continuous threads to be drawn from bushings provided with 100-400 small orifices. The threads falling from these orifices were gathered together and passed over a sizing pad onto a spool on a high-speed winder. The resulting fiber had a diameter of around 0.00022 in. ne Material contained in one glass marble 3/4 in. in diameter would yield about 97 miles of single filament). /15/
A new burst of activity began in the year 1951, when A.C.S. van Heel in Holland and H.H. Hopkins and N.S. Kapany at the Imperial College in London independently initiated studies on the transmission of images along an aligned bundle of flexible glass fibers. Kapany, B.I. Hirschowitz, and others then developed optical insulation techniques which solved most of the previous light-loss problems. The resultant glass- coated glass fibers were for many years a standard optical element for use in fiber optics. Kapany continued his work and
in 1956 first applied the term "fiber optics" by defining fiber
18
optics as "the art of the active and passive guidance of
light (rays and waveguide modes), in the ultra-violet, visible,
and infrared regions of the spectrum, along transparent fibers
through predetermined paths." /25/
During the ten year period from 1957 to 1967, interest
and experimentation increased such that significant develop-
ments and applications were made in the following areas:
ile
Z
Waveguide mode propagation.
Coupling phenomenon in adjacent fibers.
The use of scintillating fibers for tracking high energy particles.
Skew ray propagation along fibers.
The use of fiber optics as field flatteners, Focons, and image dissectors in ultra-high-speed photography.
Extension of the spectral range of fiber optics in the infrared region.
Combining the field of lasers and fiber optics in lasing fibers, fiber amplifiers, hair trigger operation in fiber lasers, and light switching by waveguide "beating."
Poobicatdon ot fiber optics to various photo- electronics devices, data processing, and photo-
copying systems. In this field of photoelectronics
ILS,
alone, fiber optics have been applied in multi- stage image intensifier coupling, high resolution cathode ray tubes, end window vidicons, and various forms of scan converters.
Application of fiber optics to the field of medicine: cardiac catheter assemblies to record and observe oxygen saturation of the blood; application of fiber-optic endoscopes for appli- cation to gastroscopy, bronchoscopy, rectroscopy, and cystoscopy; hypodermic probes; in vivo cardiac oximeter; laser coagulator for treatment of remote tissues using fiberscopes; scintillating fibers for radiology; endoscopes for the inspection of the pericardium, thoracic cavity, bone joints,
living fetus and peritoneal cavity. [25/ [36/
However, before 1967, in the field of electronics,
glass fibers were not Seriously considered as a communications medium for transmission over even moderate distances (about 1 km) because of high attenuation losses associated with glass Primary emphasis prior to 1968 was on image trans- mission devices of short length (5m) and illumination devices. *Attenuation, or loss of light in a glass fiber, is expressed
in terms of decibels per kilometer (dB/km). This subject will be discussed in more detail in Section III.
20
The first serious interest for communications was expressed by K.C. Kao of Standard Telecommunications Laboratories in England in 1968. At that time, technology was paced by the ability of industry to draw fibers of long length and low tess. /32/
In 1967-68, laboratories began development programs Beomacvelop low-loss fiber optics in response to inquiries from telecommunications laboratories. An attenuation level of 20 dB/km was set as an acceptable goal (Figure 1-1), since that level of performance was believed to be compatible with existing telecommunication systems configurations and would be sufficient to tip the economic scales in favor of optical
waveguides. /8/
S
: 10,000
=) e
rT
= | 0 i
i= |
ra) "e
= lO “e,
Oo @
gf otacsteace oe -
,o lOy LEVEL REQUIRED FOR = *
aa EFFECTIVE COMIVUNICATION :
= ° g tt yp
o IgG? IS6e 1969 1970 IS7TIl 1972 197% 1974 1975
YEAR
Figure II-1 Historical progress in low-loss waveguides: lowest attenuation achieved vs. year
21
At that time the fiber optic communication technology, involving multimode fiber optic bundles and discrete semi- conductor sources (light-emitting diodes, LEDs) and detectors (silicon positive intrinsic-negative diodes, PINs), received great stimulation and impetus from the announcement in November 1970 by Corning Glass Works of glass-fiber waveguides with 20 dB/km attenuation at a wavelength of 820 nanometers (nm). (Commercial-grade fibers up to that time had about 1000 dB/km attenuation). In 1971, Bell Laboratories developed liquid- core low-loss fibers with losses less than 20 dB/km out to 1100 nm. (/35/
- In August, 1972, the Corning Glass Works announced that they had surpassed the attenuation goals by developing fibers with an attenuation loss of 4 dB/km at wavelengths of 850 and 1060 nm. Losses between 600 and 900 nm were all below 12 dB/km. /8/ By August 1974, Bell Labs had developed a fiber- optic cable with an attenuation loss of only 2 dB/km at 1060 om. [6/
The development of low-loss fibers was not the only obstacle to overcome, however. Even the mundane problems of making connectors that worked and figuring out ways to repair a broken fiber in the field looked like serious roadblocks. There were so many problems as late at 1972 that few expected
fiber-optic systems to find anything but specialized applications
LS
until the 1990s. However, most of the earlier problems have been under parallel attack in dozens of laboratories around
the world, most notably in Russia, Japan and western European countries. The stumbling blocks of 18 months ago have virtually disappeared. ''This is one of the fastest-moving technologies
I've ever seen,"
says Don Alexander, who monitors cable develop- ments from International Telephone & Telegraph Corp.'s head- quarters in New York. /26/
"A lot of things have come to pass in one and a half
years instead of five,"
agrees Herbert A. Elion of Arthur D. Little, Inc., who has been working on optoelectronics since 1968. Elion, who has been working on fiber optics with a group of 27 clients from four continents -- both companies and govern- ment agencies -- says that spending for development efforts in fiber-optic systems topped $100 million in the past year (1974). He expects it to double in 1975-76. "People argue about the time scale," he says. ‘Some projects have been advanced from 1979 to 1976." [26/
Technologically, it appeared that it was feasible to use fiber optics in communication and data link systems. With unlimited potential for future application and the door already cracked, it only remained for both industry and the military to
expend time, effort and money in research and development programs
in order to start reaping the benefits offered by fiber optics.
Zo
2. Background of NELC A-/7 ALOFT Demonstration Program
Man has employed optical means in military communica- tions since ancient times. Early writers, such as the Greek historian Polybius (c. 205-125 B.C.), refer to the employment of visual signaling, including flags and smoke signals. Flag and light codes for naval communications were developed by sea forces during the sixteenth century. In 1875, the U.S. Navy began experimenting with electric lights for signaling. By 1916, Rankine had patented a voice communicator utilizing a vibrating mirror to modulate the optical carrier. The Navy developed a cesium vapor lamp which could be amplitude-modulated electrically at voice frequencies in 1944. Despite considerable effort and ingenuity, however, practical systems were limited to audio bandwidths until about 1961. By 1970, three advances of potential significance were reported: the development of the first injection laser which operated continuously at room temperature, the development of the first continuously operating dye laser, and the production of the first low-loss fiber optics transmission lines. These, and other electro-optical advances, such as light emitting diodes (LEDs), helped set the stage for fiber-optic communications systems. /33/
While visiting England in 1970, Dr. John M. Hood, a former student of H.H. Hopkins, recognized the suitability and
timeliness of fiber-optic techniques for naval and military
24
applications. Upon his return from England, he was instru- mental in having a Fiber Optics group established in the Electromagnetics Technology Department at NELC. The group, funded by internal research and development funds, was dedi- cated to the development of a practical technology for meeting the problems arising from the specific uses that fiber optics offers to the Navy. It was clear that a natural and obvious application was to improve the internal data links of military aircraft. It was also recognized that the potential for ship- board use was just as great. By mid-1971, various agencies of the Department of Defense (ONR, ARPA, NAVELEX and NAVAIR) had committed funds for continuing fiber-optic research. In April 1973, a Fiber Optics Development Plan was promulgated at NELC, setting forth a program for identifying and meeting the Navy's needs in the fiber optics field. This plan then became the official NAVAIR-NAVELEX development plan. It has since been superseded by the proposed DOD Tri-Service Technical Application Area Plan for Fiber Optics Communications Technology, Gated 25> March 1975. At the time of this writing, the plan has been agreed to at the working level but not yet approved at the command level. /14/
In January 1973, NELC entered into a contract with the Federal Systems Division of IBM Corporation under contract
number N00123-73-C-1665 for the design, fabrication and
ILS:
laboratory testing of a high speed, multiplex fiber-optic data link to interconnect the tactical computer and head-up display from an A-/ aircraft. The work was performed at the IBM Electronics Systems Center at Owego, New York, during the
period February to May, 1973. The final report was completed mine 1973 by H.C. Farrell and RN. Jackson. {14/ In partic- ular, the tests, made on the link between the ASN-91 computer and the Head-Up Display (HUD) took the form of performance comparisons between the fiber-optic link and the original conventional shielded wire cable, as well as experiments on special properties of the optical link. The results were conclusive: in a noise-free environment there was no detectible difference in performance between the two types of interfaces; in the presence of an electrical noise generator, however, the output display was unaffected when the signal was received via the optical channel, but it incurred serious deterioration
when the shielded cable was used. Part of the laboratory tests in this contract tested the link through the full requirements of MIL-STD-461 and MIL-STD-462 (military standard specifications on Electromagnetic Interference (EMI) and Radio Frequency Inter- ference (RFI). These tests results were the first quantitative validation that fiber optics were definitely immune to RFI and
EMI. /14/
26
The results of the IBM tests were made known to program review officials in the Navy Department and the Department of Defense. These officials recognized the need of a major feasi- bility demonstration to design and implement fiber-optic links at a full scale system level for test and evaluation. At this time, NELC made a proposal to Commander, Naval Air Systems Command (NAVAIR), for a two year program to install fiber optics in place of standard twisted-pair and coax cabling in the navigation/weapons delivery system (N/WDS) of an A-7 aircraft for test demonstration and evaluation purposes. Subsequent to this request, Dr. Malcolm R. Currie, Director of Defense Research and Engineering, submitted a memo, dated 6 August 1973, to the Assistant Secretary of the Navy for Research and Develop- ment in which he expressed confidence in the role of fiber optics technology for naval applications and thereby urged prosecution a pLocram for exploiting it. /12/
This request culminated in approval by the Assistant secretary of the Navy for Research and Development and subse- quent funding-go-ahead by OPNAV 982 and AIR360 for the imple- mentation of the A-7 Airborne Light Optical Fiber Technology (ALOFT) Demonstration. The project was initially funded in March 1974 under AIRTASK A360360G/003C/4W41X1-001. /14/
In July 1974, the Chief of Naval Material, assigned
the Naval Air Systems Command lead responsibility through
Fi
FY 1976 for the development of the fiber optics technology to fulfill military systems needs and applications. Commencing in FY 1977, the Naval Electronics Systems Command is designated to assume lead responsibility of the fiber optics development program. /11/ 3. NELC A-7 ALOFT Demonstration Approach
As soon as the AIRTASK was received by NELC in March 1974 to initiate the ALOFT Project, NELC managers and engineers consolidated plans and objectives into a formalized Development Approach. The project was to consist of a two-year program with a milestone schedule as outlined in Figure II-2. The major project phases were as follows:
(1) A six-month system analysis and design effort to be performed in part under NELC contracts to define the system performance requirements, to design the system, and to provide a system installation plan.
(2) A six-month contractual effort to fabricate and checkout the demonstration system in the contrac- tor's system integration laboratory.
(3) A three-month test and evaluation program of the demonstration system while installed in an A-/
ground simulator.
28
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(4) An eight-month test and evaluation phase of the demonstration system including aircraft modifica- tion, ground check, and flight test while installed im an A-/ test aircrare.
(5) Funds permitting, an economic analysis is to be performed concurrently with the checkout, test and evaluation of the demonstration system; the objec- tive of which will be to analyze the comparative cost and performance benefits of the fiber-optic system versus a wire interconnect system.
The possibility of utilizing Naval Postgraduate School students' theses efforts to conduct independent research and give complimentary support to the economic analysis was first discussed by NPS students and NELC (Code 1640) in early 1974. The resulting proposals of theses investigations in this area proved desirable to both NELC and NPS. See Figure II-3 for A-7 ALOFT economic analysis activity flow.
4°, A-7 ALOFT Demonstration Management Organizational otructure
The A-7 ALOFT project is assigned to NELC under the Aircraft Internal Communications Project Office, Code 1640.
A project has been established within Code 1640 for the manage- ment of this project. The basic ALOFT organizational structure
is shown in Figure II-4.
30
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Under the current program effort in the A-/ ALOFT project the economic analysis function will be expanded to include some in-house management along with Naval Postgraduate support and contractual assistance. This structure is shown in Figure II-5, which does not present the other organizations
(see NELC-TD 369 for full organization).
~ NELC CODE 1640
ECONOMIC ANALYSIS MANAGER NELC CODE 230
NPGS SUPPORT CONTRACTOR
Picume ti=5 A-7 ALOFT economic analysis organization structure
55
felis FIBERVOPTICS TECHNOLOGY AS APPLIED TO DATA LINK SYSTEMS
A. GENERAL
Recent breakthroughs in fiber-optic technology have made the application of fiber-optic waveguide systems to military information transfer entirely possible and feasible. The area of avionics data transfer will possibly be the first major application or beneficiary of fiber-optic technology. Several military utilization applications have been studied and a number of feasibility demonstrations have been made. These studies have pointed up dramatic performance and potential cost advantages for a wide range of system applications.
Engineers at the Naval Electronics Laboratory Center have summarized the important properties of fiber optics as follows: [30/
(1) Cross-talk immunity between fibers and fiber cables.
(2) Security from signal leakage and tap-in attempts.
(3) No electrical grounding problems.
(4) No short circuits which could damage terminal equipment.
(5) No ringing problems.
(6) Large bandwidth for size and weight. The increase in
bandwidth, combined with crosstalk/noise immunity,
makes miltiplexing at high data rates possible.
34
(7)
(8)
(9) (10)
Gy) (12)
(13)
Small size, light weight (glass is 1/6 the weight of copper), and flexibility - thus, ease of installation. Potential low cost - when considering common factors such as size, flexibility, equivalent bandwidth, and manufacturing quantity. The strategic availability and cost of copper as compared to glass will play a future role.
High temperature tolerance (500 to HOOO-C) .
Safety in combustible areas and hazardous cargo areas