effect of a co_2 laser pulse on transmission through fog at visible and ir wavelengths

5
Effect of a CO 2 laser pulse on transmission through fog at visible and IR wavelengths Michael C. Fowler The extinction coefficientsof laboratory generated fog at 0.63 and 10.6 Aim are monitored during and after passage of a coaxial CO 2 laser pulse of 2-J/cm 2 fluence. Pulse passage causes a slight decrease in extinction at 10.6,4mand a marked increase in this quantity at 0.63 ,jm. This effect is consistent with the significant reduction in fog droplet size, caused by absorption of energy from the pulse. The data are analyzed to pro- vide the time dependence of particle size following pulse passage, and the inferred particle growth rate is consistent with the mechanism of recondensation, onto droplets which survive the pulse passage, of water vapor driven from the fog droplets by absorption of pulse energy. For any aerosol whose particle size is sig- nificantly altered by laser pulse passage, the effect of the pulse on light extinction is determined by initial aerosol particle size and index of refraction as well as the wavelength of the light to be transmitted. 1. Introduction The use of laser radiation to clear an optical path through fog has been of interest to physicists for more than a decade. The Mullaney et al. experiments and analyses dealt with the use of low intensity cw CO 2 laser radiation to improve visible wavelength transmission through fog, and Fowler et al. 2 studied the high inten- sity cw CO 2 laser/fog interaction as it related to thermal blooming. Lowder et al. 3 studied the transmission of high energy CO 2 laser pulses through fog, and Kafalas and Ferdinand 4 and Kafalas and Herrmann 5 docu- mented the occurrence of fog droplet shattering by high fluence CO 2 laser pulses. In this paper we describe the influence of a several J/cm 2 fluence CO 2 laser pulse on the transmissivity of fog at visible and infrared wave- lengths by monitoring the transmitted power of low power visible and infrared cw laser beams coaxial with the laser pulse. Section II describes the experimental arrangement used in obtaining the transmissivity data, and Sec. III describes the data. Analysis of the data is done in Sec. IV where we infer the temporal dependence of the effective fog droplet size following the laser pulse. The analysis indicates that the fog droplets are greatly reduced in size during the laser pulse. This reduction in size greatly increases the attenuation of visible ra- diation by the fog due to increased scattering. In con- The author is with United Technologies Research Center, East Hartford, Connecticut 06108. Received 20 April 1983. 0003-6935/83/192960-05$01.00/0. © 1983 Optical Society of America. trast, the size reduction only slightly decreases infrared attenuation. The analysis further indicates that, after passage of the laser pulse, the fog droplet size increases, and the rate of increase is consistent with the mecha- nism of recondensation of water vapor from the super- saturated irradiated medium onto the droplets. At the same time, the transmissivity recovers toward its prepulse value, finally reaching it when convection of the medium acts to clear the irradiated fog from the probe beam path. 11. Experimental Setup The experimental arrangement is shown in Fig. 1. The pulsed laser output, typically 5-7 J as measured at the calorimeter C, was focused so that its e-1 radius was 1.2 cm at the cell entrance and 0.8 cm at the end of the 6-m long propagation cell. Prior to entering the cell, the pulse encountered two beam splitters. The first had a reflectivity of 90% and was used to superimpose coaxially the laser pulse on the output of a low power electric discharge CO 2 laser which was chopped at 8 kHz. The second beam splitter was transparent to CO 2 laser radiation and superimposed the two CO 2 laser beams coaxially with the He-Ne laser beam as shown. The three beams passed through the cell which was filled with fog generated by acoustic shear atomizers manufactured by the Sonic Development Corp. and described by Dunphy. 2 Before an experiment, the fog generators were run, and the fog distribution in the cell was homogenized with a circulating fan not shown in the figure. During the run, the fog generators and fan were generally turned off, and the still fog was allowed to decay to the point of transparency for the two cw lasers. 2960 APPLIED OPTICS / Vol. 22, No. 19 / 1 October 1983

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Effect of a CO2 laser pulse on transmission through fog atvisible and IR wavelengths

Michael C. Fowler

The extinction coefficients of laboratory generated fog at 0.63 and 10.6 Aim are monitored during and afterpassage of a coaxial CO 2 laser pulse of 2-J/cm 2 fluence. Pulse passage causes a slight decrease in extinctionat 10.6 ,4m and a marked increase in this quantity at 0.63 ,jm. This effect is consistent with the significantreduction in fog droplet size, caused by absorption of energy from the pulse. The data are analyzed to pro-vide the time dependence of particle size following pulse passage, and the inferred particle growth rate isconsistent with the mechanism of recondensation, onto droplets which survive the pulse passage, of watervapor driven from the fog droplets by absorption of pulse energy. For any aerosol whose particle size is sig-nificantly altered by laser pulse passage, the effect of the pulse on light extinction is determined by initialaerosol particle size and index of refraction as well as the wavelength of the light to be transmitted.

1. Introduction

The use of laser radiation to clear an optical paththrough fog has been of interest to physicists for morethan a decade. The Mullaney et al. experiments andanalyses dealt with the use of low intensity cw CO2 laserradiation to improve visible wavelength transmissionthrough fog, and Fowler et al. 2 studied the high inten-sity cw CO2 laser/fog interaction as it related to thermalblooming. Lowder et al.3 studied the transmission ofhigh energy CO2 laser pulses through fog, and Kafalasand Ferdinand 4 and Kafalas and Herrmann 5 docu-mented the occurrence of fog droplet shattering by highfluence CO2 laser pulses. In this paper we describe theinfluence of a several J/cm 2 fluence CO2 laser pulse onthe transmissivity of fog at visible and infrared wave-lengths by monitoring the transmitted power of lowpower visible and infrared cw laser beams coaxial withthe laser pulse. Section II describes the experimentalarrangement used in obtaining the transmissivity data,and Sec. III describes the data. Analysis of the data isdone in Sec. IV where we infer the temporal dependenceof the effective fog droplet size following the laser pulse.The analysis indicates that the fog droplets are greatlyreduced in size during the laser pulse. This reductionin size greatly increases the attenuation of visible ra-diation by the fog due to increased scattering. In con-

The author is with United Technologies Research Center, EastHartford, Connecticut 06108.

Received 20 April 1983.0003-6935/83/192960-05$01.00/0.© 1983 Optical Society of America.

trast, the size reduction only slightly decreases infraredattenuation. The analysis further indicates that, afterpassage of the laser pulse, the fog droplet size increases,and the rate of increase is consistent with the mecha-nism of recondensation of water vapor from the super-saturated irradiated medium onto the droplets. At thesame time, the transmissivity recovers toward itsprepulse value, finally reaching it when convection ofthe medium acts to clear the irradiated fog from theprobe beam path.

11. Experimental Setup

The experimental arrangement is shown in Fig. 1.The pulsed laser output, typically 5-7 J as measured atthe calorimeter C, was focused so that its e-1 radius was1.2 cm at the cell entrance and 0.8 cm at the end of the6-m long propagation cell. Prior to entering the cell,the pulse encountered two beam splitters. The first hada reflectivity of 90% and was used to superimposecoaxially the laser pulse on the output of a low powerelectric discharge CO2 laser which was chopped at 8kHz. The second beam splitter was transparent to CO2laser radiation and superimposed the two CO2 laserbeams coaxially with the He-Ne laser beam as shown.The three beams passed through the cell which wasfilled with fog generated by acoustic shear atomizersmanufactured by the Sonic Development Corp. anddescribed by Dunphy.2 Before an experiment, the foggenerators were run, and the fog distribution in the cellwas homogenized with a circulating fan not shown in thefigure. During the run, the fog generators and fan weregenerally turned off, and the still fog was allowed todecay to the point of transparency for the two cw lasers.

2960 APPLIED OPTICS / Vol. 22, No. 19 / 1 October 1983

PROPAGATION CELL

Fig. 1. Schematic of apparatus.

During this time, the pulsed laser operated at a rate of0.1 Hz. The throughput of this laser was sampled withthe salt wedge, WI, onto a 32 element pyroelectric lineardetector array, designated LDA in the figure. Eachelement of the LDA was 0.9 mm wide so that the LDAoutput provided a 32-mm wide spatial profile of thelaser pulse fluence transmitted through the fog. TheLDA output was stored on videotape, digitized andstored on a computer disk for analysis. The cw beamswere sampled by reflecting a portion of each off a sur-face of the salt wedge W2 onto a detector. For the CO2laser, the detector D was a gold-doped germaniumphotoconductor whose output was amplified using alock-in voltmeter, designated L in the figure, and re-corded on the chart recorder R. The He-Ne beam wasdirected onto a photodiode, P, whose active area andrise time were 1.0 cm2 and 0.4 ,usec, respectively, andthis output was also recorded either on R or on an os-cilloscope.

Ill. Experimental Results

A. Pulsed Laser Transmissivity

In Fig. 2(a) we show the linear pyroelectric detectorarray output for both a laser pulse transmitted throughthe empty propagation cell, denoted Jo, and a pulsetransmitted through the cell filled with fog, denoted J.The LDA output is a spatial profile of the transmittedpulse fluence, and the quantity ln(Jo/J) is equal to theproduct of the extinction coefficient, e, of the fog for theradiation and the cell propagation length 1. We alsoshow the value of El derived from the profiles Jo and Jin Fig. 2(b), along with the Jo profile. We see that eldecreases with increasing laser fluence, being -1.2 forthe maximum Jo value which was -2 J/cm 2 at the cellentrance and 1.6 at Jo values below 1 J/cm2. Thesedata show that the laser pulse was able to alter the op-tical characteristics of the fog, decreasing the degree of10.6-Mtm extinction by 25% on a time scale comparableto the laser pulse width, which was 2-,usec(FWHM) inthese experiments.

B. Probe Laser Transmissivity

Figure 3 is a time history of the CO2 and He-Ne probelaser power transmitted through the fog filled cell ir-radiated with 2-J/cm2 peak pulsed CO2 laser fluence.In this particular experiment the prepulse values of Elexperienced by the CO2 and He-Ne beams are 0.14 and0.77, respectively. Following passage of the pulse, the

transmitted cw CO2 power increases to a value whichcorresponds to a value of 0.097 for el, a 30% decrease inthis quantity. This is consistent with the change ob-served in the pulsed laser transmission, and we associatethe 300-msec rise time in the recorded CO2 power signalwith the response time of the chart recorder. In con-trast, the El value for the He-Ne laser probe beam ex-periences a 260% increase following passage of the pulse.This rapid increase is followed eventually by a slow,several second long, decrease in El which eventuallyreturns to its base line value which is slowly decreasingdue to decay of the fog in the cell. In a third experi-ment, we left the fog generators on, thereby setting upconvective mass transport of fog in the cell. In this case,the change in el at 0.63 ,um occurred only in the form of

a)

DETECTORSIGNAL - mV

b)

80

4C

10 1 "I - j - I

so~~~J0- I I - Ir

0 - Ett2.

2

1.

0 8.2 16.4 24.6 32.8DETECTOR POSITION - mm

.5 - L 1 1 1- I I

.0 _D.5 --L-AIf Jo (Volts)I

10 13.0 16.0 19.0 22.0 25.0DETECTOR POSITION - mm

Fig. 2. (a) Spatial distribution of transmitted pulse fluence with thecell empty, Jo, and filled with fog, J. (b) Spatial distribution of el,

equal to ln(Jo/J), using the data of (a), and Jo, showing the pulsefluence's ability to decrease e on the time scale of the pulse width, 2

jisec.

e I= 0.097) 1 -CO2

1° - HeNe{

SIGNAL 1;<

ce1=2.8 v

0 2 4 6 8

TIME - sec -

Fig. 3. Time history of transmitted probe beam power. Passage ofthe laser pulse decreases opacity of fog at 10.6 jm but increases it at

0.63 jim.

1 October 1983 / Vol. 22, No. 19 / APPLIED OPTICS 2961

KEEE dUMEAI - PREPULSEDETECTOR 200 M l SIGNAL LEVELSIGNAL, 1mmr~m

m 100 1 ]o

0

0 20 40 60 80 100TIME, msec

Fig. 4. Oscillogram of transmitted He-Ne probe beam power. Atno time does El decrease below its prepulse value but rises to a maxi-mum in 35 msec and returns to its prepulse value in 100 msec as

convection moves fresh unirradiated fog into the probe beam.

100

E(063/t) 10E(1 0.6A)

0.1 1.0 10- itm

Fig. 5. Extinction coefficient ratio vs . The dots are the valuescalculated using the code of Ref. 8, and the fine structure oscillations

are interpolated using the formula found in Ref. 11.

a narrow spike, similar to the initial spike in the Fig. 3He-Ne data, and we show an oscillogram of the trans-mitted He-Ne signal in these conditions in Fig. 4. Theprepulse transmitted He-Ne laser power in this ex-periment was approximately half of the empty cell sig-nal so that the prepulse value of El was 0.69, essentiallythe same as in the case of the experiment in Fig. 3. Theoscillogram shows that el at no time falls below itsprepulse value but rather increases to a value of 2.6 overa time span of 35 msec before returning nearly to itsprepulse level at 100 msec. The relatively rapid returnof el to its prepulse level in this experiment comparedwith that associated with Fig. 3 is attributed to theconvective cleanout of the irradiated medium from theHe-Ne beam by the fog generator driven wind.

IV. Data Analysis

The data presented in Sec. III show that irradiationof fog by a 2-J/cm2 laser pulse affects the extinctioncoefficients at 10.6 and 0.63 m in ways that differ bothin sign and magnitude. Past work has shown that theabsorption of CO2 laser energy by fog reduces thedroplet size through evaporations 6 and droplet shat-tering.4 5 In this section, we use the data to derive thetime history of the effective particle size in our ex-periments with the aim of determining the physicalprocesses which determine the observed behavior of theextinction coefficient. The magnitude of is influenced

by the droplet size distribution in our fog samples.Dunphy2 has inferred that this distribution is fairlynarrow for freshly generated fog, but the effects of ir-radiation followed by recondensation of evaporatedwater onto the surviving droplets certainly change thesize distribution significantly from its original form.However, in the following discussion we assume amonodisperse size distribution in order to facilitate theanalysis and gain insight into the important physicalprocesses operating in these experiments.

The two-probe beam results of Fig. 3 provide us withknowledge of e at two wavelengths, which can be usedto determine the value of r. 7 We use an exact lightscattering computer code8 to calculate T, shown in Fig.5, as a function of the extinction coefficient ratio for thewavelengths 10.6 and 0.63 Am for a monodisperse sizedistribution, and using this in conjunction with the datain Fig. 3 we obtain the time dependence of T shown asopen circles in Fig. 6.

Because of the slow time response of the chart re-corder, the data in Fig. 3 are quantitative only to timeslonger than -200 msec after the laser pulse. The opencircles in Fig. 6 indicate that r is essentially constantfrom 200 to 700 msec and then increases to its prepulsevalue, reaching the latter at -1.5 sec. The latter timeis in good agreement with the calculated time neededfor the medium, heated by absorbing energy from thelaser pulse, to rise by buoyant convection and becomedisplaced one beam radius, effectively removing theirradiated medium from the probe beam. This time isgiven by (2aopCPT/a-J) where a is the probe beamradius (1 cm), p the medium mass density, Cp its specificheat, and T its temperature; g is the acceleration bygravity; a is the absorption per unit path length of fogat 10.6 /,m; i7 is the fraction of the absorbed energyconverted to gas heating,9 and J is the pulse fluence.For our experiments this time is 1.5 sec and is markedby the vertical arrow in Fig. 6.

1.0

r (m)

0.1

0.01 0.001 I I . . .

0.01 0.1t - sec

10

Fig. 6. Time dependence of effective droplet radius. Open circlesrepresent data from Fig. 3; closed circles represent data from Fig. 4.The horizontal arrow denotes for unperturbed fog. The verticalarrow denotes time of onset for buoyancy driven convective cleanout

of probe beast.

2962 APPLIED OPTICS / Vol. 22, No. 19 / 1 October 1983

To obtain T at shorter times we use the data in Figs.2 and 4. The data in Fig. 2 simply indicate that theinitial change in T occurs on a time scale of the order ofthe laser pulse width, 2 Asec. The initial values of T andthe droplet number density n in the Fig. 4 experimentare essentially the same as in the Fig. 3 experiment, 2.4,im and 3800 cm-3 as calculated from the prepulse valueof e and the calculated 8 value of the extinction crosssection. The product of n and the average droplet massis the initial liquid water mass density in the fog, 0.22g/m3. Passage of the laser pulse causes some of thismass to be evaporated 6 9 to gaseous water, supersatu-rating the irradiated air with water vapor, and the re-maining mass to be redistributed in a larger number ofsmaller droplets as a result of shattering of the initialdroplets.4 5 Of the newly formed droplets, the smallestwill evaporate under the influence of surface tensioneffects while the larger will increase in size by the con-densation of water from the supersaturated gas phase.This situation is described by the following equation forparticles small enough to shed effectively the heat ofcondensation to the surrounding air10:

dad = 27rG(S - a/r), (1)dt

where o- is the droplet cross section, S is the fractionalsupersaturation of the air by water vapor, G is theproduct of the water/air diffusion coefficient and theprepulse water vapor mass density divided by thedensity of liquid water, and air is the term corre-sponding to the surface tension effect mentioned above.In analyzing the data of Fig. 4, we assume that transportof unirradiated fog into the probe beam is nil on thistime scale and that the evaporation of the smaller par-ticles and the condensation of vapor onto larger onesproceed so as to cause the liquid water mass loading Cof the irradiated medium to remain essentially at itspostpulse value,

4C =-47r3 PL, (2)

3

where PL is the mass density of liquid water. Therefore,as the droplet number density n decreases, T increasesand the extinction coefficient at constant mass loadingec (T) is given by

,E,(r) = 3Ca/47r 3 pL. (3)

Using for cr the calculated values8 for 0.63 gim, thefunction e (r) exhibits a maximum at F = 0.45 ,im.Assuming that the minimum in the transmitted He-Nesignal in Fig. 4 corresponds to c, passing through thismaximum, we find that a value of 0.082 g/m3 for C isneeded to cause c, given in Eq. (3) to equal the maxi-mum value in e indicated by Fig. 4, and we present theresulting function e, (r) in Fig. 7 which also shows thevalue of e(t) inferred from the Fig. 4 data. The timehistory of r is obtained by matching r with t for equalvalues of ec (F) and e(t), and we present r(t) obtained inthis way as closed dots in Fig. 6. We interpret theseresults as indicating that r increases approximately ast1 /2 for times less than -100 msec. This is consistent

t - sec001n 01 1.0~~~~~~~~~~~~~~.1.0 _ I I I ' - I I I I I I ' I

C-

0.01 - , , , , _l , , , , j l

~~~~~~~01 1.0 'UC(r

0.01

0.1 1.0

r -Am

Fig. 7. Functions e(t) from the Fig. 4 data and ec(r) calculated fromEq. (3) for C = 0.082 g/m3 . The square is the prepulse value of e andr. The straight line is calculated from Eq. (1) with S calculated using

this value of C and neglecting air.

with the linear dependence of r2 on time predicted byEq. (1) with the air term neglected. Neglecting thesurface tension term and setting GS equal to the prod-uct of the diffusion coefficient and the droplet massloading change following the laser pulse, we calculate2.5 X 10-4 cm sec1 /

2 as the slope of r vs t, and this curveis drawn in Fig. 6. The agreement between the exper-imental points and the curve is good, particularly so atearly times when the assumption of constant liquidmass loading is expected to be most valid. At latertimes we would expect C to increase due to convectivecleanout of the probe beam so that the curve ec (T) is toolow and the inferred value of r is too small. This effectmay in part explain the failure of the derived value ofr at late times in Fig. 6 to approach its prepulse value,whereas e(t) does approach its prepulse value which isdenoted in Fig. 7 by the solid square.

V. Summary

We have carried out experiments to determine thetime history of the transmission of fog at visible, 0.63-,im, and infrared, 10.6-,um, wavelengths during andfollowing the passage of a CO2 laser pulse. The fogtested had inferred values of average particle radius andmass loading of 2.4 ,m and 0.22 g/m:3, respectively, andthe peak pulse fluence was 2 J/cm 2 . We found thatpulse passage resulted in a 30% decrease in extinctioncoefficient at 10.6 Am but a much larger 260% increaseat 0.63-,um wavelength. The latter is due to the sig-nificant reduction in average droplet size, presumablydue to both evaporation and shattering, driven by ab-sorption of the pulse energy, coupled with the existenceof a maximum in cc, which is dominated by photonscattering8 at 0.63 gim, at 0.45-,m droplet radius. Thetime at which the minimum in visible transmission isreached is determined by the average droplet size fol-lowing pulse passage and the rate of droplet growthwhich in turn is governed by the recondensation ofmaterial, evaporated by absorbed pulse energy, onto thesurviving droplets. The radius for maximum radiation

1 October 1983 / Vol. 22, No. 19 / APPLIED OPTICS 2963

1 .o 100.1

scattering scales essentially as the ratio A/(m - 1),11where m is the real part of the index of refraction andA is the wavelength, so that transmission is expected todecrease when the prepulse value r(m - 1)/A exceeds0.24 and to increase when this quantity is smaller than0.24, which was the case for our measurements at 10.6gim. This maximum is less prominant when has asignificant contribution from photon absorption,12 andso the postpulse behavior of e for an aerosol will dependon its material properties and prepulse size as well as thewavelength at which measurements are being made.

The invaluable assistance of Aristotle Parasco insetting up and carrying out these experiments isgratefully acknowledged by the author. This work wascarried out with the support of the U.S. Army MissileCommand under contract DAAH01-81-C-1067.

References1. G. J. Mullaney, W. H. Christiansen, and D. A. Russell, Appl. Phys.

Lett. 13, 145 (1968).2. M. C. Fowler, J. R. Dunphy, and D. C. Smith, "Laser Propagation

Experiments-Aerosol and Stagnation Zone Effects," UTRC Re-port R77-922578-13 (1977), p. B41.

3. J. E. Lowder, H. Kleiman, and R. W. O'Neil, J. Appl. Phys. 45,221 (1974).

4. P. Kafalas and A. P. Ferdinand, Appl. Opt. 12, 29 (1973).5. P. Kafalas and J. Herrmann, Appl. Opt. 12, 772 (1973).6. M. C. Fowler, United Technologies; unpublished.7. T. S. Chu, IEEE J. Quantum Electron. QE-3, 254 (1967).8. A. J. Cantor, "A Mie Scattering Computer Program," United

Technologies Report UTRC77-28 (1977).9. J. Wallace, "Formulation of the Analysis for Nonlinear Aerosol

Thermal Blooming," Far Field, Inc., 1981.10. N. H. Fletcher, The Physics of Rainclouds (Cambridge U.P.,

1962), pp. 122-127.11. H. C. Van de Hulst, Light Scattering by Small Particles (Wiley,

New York, 1957), p. 176.12. Ref. 11, p. 179.

NEW FIBER-OPTICS MARKET WORTH $475MILLION IN 1990

Fiber optics has already proved itself in commercial com-munications, particularly for telephone trunk connections andthose between central office systems, but another set of appli-cations, using a different group of optical components, is aboutto become viable, according to a recent market study by Frost& Sullivan. Short-haul use of fiber optics in computer systems,instrumentation, process control, medicine, local area networks,and the military will generate $475 million (constant 1982 dollars)in annual component sales by 1990, up from $47 million lastyear, says the 255-page report. The Non-TelecommunicationsFiber Optic Component Market (#1168).

Components required for these generally under 4-km usesare usually not the same as those needed for telecommunica-tions. While laser diodes are preferred for long distance appli-cations, LED emitters are sufficient for the lower data trans-mission rates in most short-haul uses. The costly avalanchephotodiodes needed for telecommunications purposes can bereplaced by cheaper PIN photodiodes. While GRIN fibers areused in telecommunications, step-index fibers are sometimesused for short-haul. The short-haul transmission environmentmay be more hostile than long-distance, also affecting compo-nents needed to do the job.

Emitters and transmitters for the short-haul and militarymarkets, worth $10 M in 1982, should increase to $115 M by1990. Detectors and receivers volume will rise from $7 M to$90 M during the period. Fiber and cable sales will jump from1982's $25 M to $230 M in 1990. The market for connectorsand couplers in nontelecommunications applications shouldincrease to $40 M from $5 M during the eight years.

The report identifies the military/aerospace segment as thelargest, advancing to $200 M in 1990 ($30 M 1982). The pro-

cess and machine control market is a distant second, with $80M sales expected in 1990 ($6 M 1982). The computer segment,comprising computer-to-computer, computer-to-terminal andintracomputer uses, will grow from $5 M to $70 M in the period,and biomedical applications from $3 M to $50 M. The com-mercial/business segment, including both networks and intra-machine use, will increse to $45 M ($2 M). The consumermarket, which includes automotive uses, was valued at only $1M in 1982, but is expected to be worth $30 M in 1990.

These forecasts assume continued progress in standardizationand cost-lowering, which are discussed in detail in the report,along with supplier analyses. Honeywell, Hewlett-Packard, andMotorola are the current leaders in this market.

A separate section of the study is devoted to fiber-opticsensors and transducers and their developers; the market isexpected to be worth $100 M by 1990. New trends in tech-nology and industry organization are examined, including theemergence of joint component design arrangements betweenfiber or semiconductor makers and connector makers. Theprice of report #1168 is $1250. For more information, contactCustomer Service, Frost & Sullivan, Inc., 106 Fulton Street, NewYork, N.Y. 10038. Phone 212-233-1080.

U.S. Nontelecommunications Fiber-Optic Component Market by use (inconstant 1982 $ millions)

1982 1983 1990Use ($M) ($M) ($M)

Computer 5 8 70Industrial/process 6 9 80Biomedical 3 5 50Commercial/business 2 3 45Consumer 1 2 30Military/aerospace 30 44 200

TOTAL 47 71 475

2964 APPLIED OPTICS / Vol. 22, No. 19 / 1 October 1983