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Ultra-low bending loss single-mode fiber for FTTH

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DOI: 10.1109/JLT.2008.2010413

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376 JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 27, NO. 3, FEBRUARY 1, 2009

Ultra-Low Bending Loss Single-Mode Fiberfor FTTH

M.-J. Li, Fellow, IEEE, OSA, P. Tandon, D. C. Bookbinder, S. R. Bickham, M. A. McDermott, R. B. Desorcie,D. A. Nolan, Fellow, IEEE, OSA, J. J. Johnson, K. A. Lewis, and J. J. Englebert

Abstract—A new ultra-low bending loss single-mode fiber withring comprising nanometer sized features is designed and manu-factured. Bending loss less than 0.1 dB/turn at 1550 nm and a bendradius of 5 mm is demonstrated. Other optical parameters of thefiber are fully compatible the standard telecommunications gradesingle-mode fibers.

Index Terms—Bend-insensitive fiber, fiber-to-the-home (FTTH),nano-engineered fiber.

I. INTRODUCTION

B END insensitive single-mode fibers are attractive forfiber-to-the-home (FTTH) applications because they can

lower the installation costs and improve system performance[1]. For multiple dwelling units (MDUs) and in-home wiringapplications, bend radii in the range of 5 mm are very commonand bending losses must be kept to a minimum. Bending lossesof less than 0.1 dB/turn will ensure robust network performanceunder practical bending conditions [2], such as tight 90 cor-ners, corners under load, fixation by stapling and excess cablestorage in tightly confined spaces.

Several conventional approaches have been proposed toreduce the bending loss of single-mode fibers. They includereducing the mode field diameter [3], depressed cladding [4],adding a low index trench [5]–[7]. Although conventional fiberdesign approaches deliver fibers that meet the standard require-ments, their bending losses are well above the required 0.1dB/turn and further improvements would be necessary to meetthe demanding requirements of low cost FTTH installations.

Photonic crystal structures can offer advantages over conven-tional fiber structures in fiber designs, because air holes havea much lower refractive index and different dispersion prop-erties than those of the silica glass. Both the bandgap guidingand average index guiding mechanisms have been studies inten-sively in the literature [8]–[10]. Periodicity of the holey struc-ture is essential for the bandgap guiding [8], but is not criticalfor the average index guiding [10]. In particular, it has beendemonstrated that light can be guided in fiber with randomlydistributed air holes cladding [11], [12]. Hole-assisted fiber de-signs have been proposed to reduce fiber bend loss [13], [14].

Manuscript received June 27, 2008; revised September 29, 2008. Currentversion published February 13, 2009.

The authors are with Corning Inc., Science & Technology Division, Corning,NY 14831 USA ( e-mail: lim@corning.com).

Color versions of one or more figures in this paper are available online athttp://ieeexplore.ieee.org.

Digital Object Identifier 10.1109/JLT.2008.2010413

These hole-assisted fibers have shown superior bending perfor-mance but they are not compliant with ITU-T RecommendationG.652. In addition, the process for making hole-assisted fibersis also much more complicated than conventional fiber makingprocesses, making the fibers less attractive for large scale andcost-sensitive FTTH implementation.

In this paper, we report a new bend insensitive fiber whichuses nanoStructures™ technology in its fiber design. To the bestof our knowledge, this is the first fiber that exhibits 1550 nmbending loss less than 0.1 dB/turn at 5 mm bend radius and isfully compatible with standard single-mode fibers and can bemanufactured using a standard outside vapor deposition (OVD)process suitable for large scale manufacturing. Excellent perfor-mance was obtained for fiber cables under different tight bendconditions, demonstrating that the fiber is suitable for FTTH ap-plications.

II. NANO-ENGINEERED BEND INSENSITIVE FIBER DESIGN

Designing bend insensitive fibers for FTTH poses significanttechnical challenges. The first challenge is to reduce the bendingloss to meet the requirements of harsh, copper cable-like han-dling conditions in MDU applications. This requires a bend-insensitive fiber to have a bend loss at 1550 nm of less than0.1 dB/turn at a bend radius of 5 mm. As a reference point, thebend loss of standard single-mode fiber at 1550 nm is typically20 dB/turn at the same bend radius. This implies a bend lossreduction factor of over 200, which is very difficult to achieveusing conventional dopants. The second challenge is to meetthe requirements of backward compatibility with the standardsingle-mode fibers imposed by the telecom industry standards.The bending and backward compatibility requirements put se-vere constraints on the fiber design space.

There are two types of approaches in designing fibers withimproved bend performance. One type is the conventional de-sign approach by changing the index profile with commonlyused dopants such as germanium and fluorine. Three conven-tional designs are shows in Fig. 1(a)–(c). Fig. 1(a) is a reducedmode field diameter (MFD) design with a simple step index pro-file. While reducing the MFD can improve the bending perfor-mance, it will change other fiber parameters significantly too,such as cutoff wavelength, zero-dispersion wavelength, disper-sion slope, splice/connector loss. Considering the bending per-formance and the backward compatibility, the MFD at 1310 nmcan be reduced to 8.6 m compared to 9.2 m in typical stan-dard single-mode fiber. With the reduced MFD, the 1550 nmbend loss is lowered to about 2 dB/turn at a bend radius of 5 mm,which is still well above the bend loss requirement for MDU ap-plications. The addition of a low index layer around the core as

0733-8724/$25.00 © 2009 IEEE

LI et al.: ULTRA-LOW BENDING LOSS SINGLE-MODE FIBER FOR FTTH 377

Fig. 1. Fiber designs for reducing bending loss: (a). Reduced MFD design. (b)Depressed cladding design. (c) Trench fiber design. (d) Hole assisted design. (e)Photonic crystal design.

shown in the depressed cladding design in Fig. 1(b) offers a littlemore flexibility in tuning the fiber zero-dispersion wavelengthin the 1310 nm window. However, with backward compatibilityconstraints to the fiber design, the bending performance andother optical parameters that can be achieved with the depressedcladding design are essentially the same as the simple step indexdesign with reduced MFD. The trench fiber design shown inFig. 1(c) may offer the best approach among the conventionalfiber designs. The low index trench reduces the power in thecladding region outside the trench, thus improves the bend loss.However, in order to keep the cable cutoff wavelength below1260 nm required by the standards, the trench volume, whichis defined as the product of the area and the relative refractiveindex change of the trench, has to be small enough to allow the

mode to tunnel into the cladding. Typical bending perfor-mance of this trench fiber is about 0.5–1 dB/turn at 1550 nmwith a bend radius of 5 mm. All of these conventional designshave similar limitations and cannot deliver the desired bendingperformance without compromising the other optical parame-ters required by the standards.

Another type of design approach is to use air holes either ina hole assisted fiber shown in Fig. 1(d) or a photonic crystalfiber or photonic band-gap fiber shown in Fig. 1(e). While verygood bending performance can be achieved with this type of de-sign, maintaining compatiblity with standard single-mode fibershas proven to be very difficult. In addition, the manufacturingprocess for this type of fiber is very complicated, and is not suit-able for delivering high fiber volume for FTTH deployment.

The new fiber design presented in this paper is based onan innovative technology, called nanoStructures™ technologyfor making optical fibers. This is an engineering breakthroughtechnology that adds a new dimension to the conventionalfiber design space. This new technology enables new fiberdesigns having superior bend performance that meets the FTTHrequirements and, at the same time, maintaining compatibilitywith large scale manufacturing, legacy fiber plant and existingfield installation equipment and procedures.

Fig. 2 shows a schematic of the fiber design, which con-sists of a germania-doped core and a nano-engineered ring inthe cladding. The ring consists of nanometer-sized gas filled

Fig. 2. Schematic of bend insensitive fiber with nano-engineered ring.

voids that are incorporated in the glass during the fiber pro-cessing. These voids are non-periodically distributed in the ringcross-section. The cross-sections of the voids are circular andhave diameters ranging from several dozens to several hundredsof nanometers. The void fill fraction can be designed to be be-tween 1 to 10 percent depending on the ring dimension. Thevoids are sealed and non-periodically distributed along the fiberwith void lengths ranging from less than one meter to severalmeters. The refractive index profile corresponding to the fiberin Fig. 2 in one cross section can be interpreted schematicallyto be a combination of individual index components of silicaand voids, as shown in Fig. 3. It is worthwhile to point out thatthe refractive index profile of the core is axially symmetric, butthe refractive index profile nano-engineered ring is not axiallysymmetric due to the non-periodic distribution of voids. Theexact void distribution profile can be determined by the Scan-ning Electron Microscopy (SEM) technique, as described laterin the paper. The core has a relative refractive index changesof about 0.34%, and core radius about 4 m. In a cross-sectionalindex profile, the ring contains many low-index regions withthe index value of 1 ( % relative to pure silica). Be-cause of the non-periodic arrangement of voids, the dimension

of each low index region and the space between two ad-jacent low index regions are not constant. The nano-engineeredring is place at a radius of about 8–14 m and a thickness ofabout 2–10 m depending on the void fill fraction. The refrac-tive index profile of the void filled region is significantly dif-ferent from that of conventionally doped silica. The size char-acteristics of voids and void fill fraction significantly affect theoptical properties of the nano-engineered region, thereby influ-encing the fiber performance.

The nano-engineered ring design offers several advantagescompared to other technologies. First, the wavelength depen-dence of refractive index of glass having nanometer sizedfeatures is very different from that of glass with conventionaldopants such as GeO , F, Al O , P O used in fiber manu-facturing. Refractive index profiles of standard optical fibersare typically measured using Refracted Near Field (RNF)method (e.g., High Resolution Optical Fiber Analyzer, Model#NR-9200 HR, EXFO Electro-Optical Engineering). Our at-tempts to measure the refracted index profile of the void filledregion using the RNF technique have not been successful.

378 JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 27, NO. 3, FEBRUARY 1, 2009

Fig. 3. Relative index profile of nano-engineered fiber design.

The results showed index levels similar to that of silica, thusindicating the void filled glass optically behaves significantlydifferent from that of conventionally doped silica. For guid-ance and directional purposes only, we modeled the effectiverefractive index of void filled glass considering it to compriseof periodically distributed nanometer-sized voids. While theabove approach is unlikely to yield the absolute index of thevoid region accurately, it is expected to provide insights intoeffective refractive index sensitivity on the wavelength and voidmicrostructure characteristics. The effective index is calculatedfrom the propagation constant of the fundamental space-fillingmode by [15]

(1)

where is the propagation constant of light in the freespace. To determine the fundamental space-filling mode, we usea vectorial finite element method to solve Maxwell equationswithin a unit cell of a periodic structure. Two periodic structuresare modeled: triangular lattice and square lattice. It is found thatthe structure of lattice does not alter the effective index valuevery much. The effective index is mostly determined by the voidsize and the void fill fraction. Fig. 4 compares the relative refrac-tive index changes as a function of wavelength for a nano-engi-neered glass with voids and silica doped with fluorine. The rel-ative refractive index change is defined as follows:

(2)

where is the refractive index of pure silica, is the effectiveindex for the nano-enginneered glass, or the refractive index offluorine doped glass. For the nano-engineered glass, the diam-eter of voids is 400 nm and the void fill fraction is 2.5%. Forthe fluorine doped glass, the fluorine doping level is about 2.2%by weight. It can be seen that the refractive index of nano-en-gineered glass has much stronger wavelength dependence thanthat of fluorine doped glass. The index change for nano-engi-neered glass increases with wavelength, while the index change

Fig. 4. Comparison of relative refractive index changes of nano-engineered andfluorine doped glass.

for fluorine doped glass is nearly flat around the 1550 nm wave-length range. This characteristic of nano-engineered glass al-lows us to design fibers with low bend loss in the 1550 nmwindow while maintaining a cable cut-off wavelength below1260 nm.

A second advantage is that large negative index changes canbe made with nanometer sized features. A relative index changeas high as several percent can be achieved by using a nano-engineered design. Such a high index change is very difficultto realize using the conventional fluorine doping technology.

Third, the scattering property of a glass having nanometer-sized voids also has strong wavelength dependence. Light atshorter wavelengths has higher scattering losses than at longerwavelengths, which facilitates the suppression of higher ordermodes bounded by the nano-engineered ring. This feature helpsalso to keep the cutoff wavelength low.

These new features described above allow fiber designs withmuch better bending performance and with other optical pa-rameters compliant with the standards. The bend performanceof a fiber with a low index ring in cladding is determined bythe volume of the ring, which is defined by the ring area andthe index depression. Increasing the ring volume will improvethe bend performance. But the ring also makes the higher order

mode more confined in the core region, which increasesthe cutoff wavelength. If the ring volume exceeds a certainmaximum value, the fiber will exceed the 1260 nm cable cutoffwavelength limit imposed by the G.652 standard. For a fluorinedoped ring, the ring volume is constant in the wavelength rangebetween 1200–1600 nm because the index does not changemuch with wavelength. For a nano-engineered ring design, thering volume increases with the increase with wavelength. Thisoffers better bend resistance at the more bend sensitive, longeroperating wavelengths. At shorter wavelengths the ring volumeis reduced, which can keep the cable cutoff wavelength below1260 nm. As a consequence, the nano-engineered fiber exhibitsbetter bend performance at 1550 nm while retaining completebackwards compatibility with G.652 standard single-modefibers. To quantify the fiber design advantages, we have calcu-lated the bending loss of nano-engineered and fluorine trench

LI et al.: ULTRA-LOW BENDING LOSS SINGLE-MODE FIBER FOR FTTH 379

Fig. 5. Calculated bending loss at 1550 nm for nano-engineered and trenchfibers designs.

Fig. 6. SEM picture of a nano-engineered fiber cross section.

fibers using a bend loss model. Both fibers had the same singlemode core design. The inner radius and ring thickness of thenano-engineered ring and the fluorine trench were chosen suchthat the cutoff, MFD and dispersion properties were compa-rable. To get different cutoff wavelengths and different bendinglosses, the ring width and void fraction were adjusted for thenano-engineered ring and the width and refractive index arechanged for the fluorine trench. In our modeling, a bent fiberis transformed into a straight fiber with an equivalent refractiveindex distribution as suggested in [16],

(3)

where is the bending radius, and the fiber is bent in the x-axis.The numerical modeling is based on a finite element methodsolving the fully vectorial Maxwell equations used in a previousstudy [17]. A circular perfectly matching layer (PML) is imple-mented at the fiber surface to emulate the effect of an infinitedomain in the finite element model. With the PML, the propa-gation constant of a mode becomes complex with the real part

TABLE ITYPICAL OPTICAL PROPERTIES OF NANO-ENGINEERED FIBER

related to the effective index and the imaginary part related tothe bending loss. The bending loss of the fiber in a par-ticular mode can be calculated from the imaginary part of thepropagation constant so that,

(4)

Fig. 5 shows the bending loss at 5 mm radius of the two fibersas a function of cable cutoff wavelength. The cable cutoff wave-length is defined as the wavelength at which the loss of the firsthigher order mode, mode, has a total attenuation of 19.2dB for a 22 m long fiber with two 80 mm diameter loops as de-fined in the TIA/EIA FOTP80. The results in Fig. 5 show that thenano-engineered fiber has a bending loss of less than 0.1 dB/turnin the cable cutoff region between 1140–1260 nm, which is onetenth of the bend loss of the trench fiber.

III. FIBER CHARACTERISTICS AND PERFORMANCE FOR FTTHAPPLICATIONS

We made fibers with nanometer sized features using the out-side vapor deposition (OVD) process [18]. To make the nano-en-gineered ring, silica soot was deposit on the glass core cane first.Then the preform was consolidated in a consolidation furnace anitrogen atmosphere around 1450 C to form a glass ring con-taining voids. The preform was further overcladded with silicasoot and consolidated in a helium atmosphere to produce a finaloptical perform. In the draw process, the voids are stretched intothin elongated voids.

Fig. 6 shows a SEM picture of an optical fiber cross section.Also shown in the inset of the figure is a close-up of the coreand the void filled regions. The void fill fraction in the ringregion was approximately 3 percent with an average diameterof approximately 200 nm. The total fiber void area percent(area of the voids divided by total area of the optical fibercross-section 100) was about 0.1 percent. Experimental fiberresults demonstrate that the nano-engineering fiber technologyis compatible with the OVD process and suitable for large scaleproduction. Typical measured optical properties of the fibersamples are summarized in Table I. The optical parametersin Table I are fully compliant with the G.652D standards.The fibers also show excellent attenuation performance in thesingle-mode wavelength region.

Bending losses of the nano-engineered fibers were measuredusing mandrels with different radii. For each radius, the mea-surement was made using 5 turns to increase the accuracy. Fig. 7

380 JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 27, NO. 3, FEBRUARY 1, 2009

Fig. 7. Comparison of bending performance of nano-engineered fibers withstandard single-mode fiber and trench fibers.

compares typical bend losses as a function of bend radius for thenano-engineered fiber, standard single-mode fiber and trenchfiber designs at 1550 nm. This figure shows that the bendingperformance of nano-engineered fiber is about 500 times betterthan the standard single-mode fiber, and 6–10 times better thanthe trench fibers. The average bending loss at 5 mm radius is0.03 dB/turn. To the best of our knowledge, this is the lowestbending loss ever reported for a G.652D compliant single-modefiber.

We also made quasi-single-mode fibers with thick rings usingnanoStructures technology. While these fibers do not meet thecutoff requirement of G.652, they can be used as a single-modefiber if a restricted launch into the core is used. The advantageof this type of fiber is that the bending loss is even lower. As anexample, measured bending loss of a quasi-single-mode fiber isshown in Fig. 7. The bending loss of this fiber is less than 0.01dB/turn at 5 mm bend radius and less than 0.001 dB/turn at 10mm bend radius, which are similar to the bend losses of the hole-assisted bend resistant fibers reported in [13] and [14]. However,the manufacturing process for making quasi single-mode fibersusing nanoStructures technology is much simpler compared toprocesses used for making hole-assisted fibers.

We also evaluated fusion splicing performance for thesenano-engineered fibers at both 1310 and 1550 nm wavelengths.Both homogeneous splices between our bend-insensitivefibers, and heterogeneous splices between these and standardsingle-mode fibers were made and tested. The fusion splicerwas a Fujikura FSM 40S and the factory preset multimodeprogram was used. The splicing results at 1310 nm are shownin Fig. 8. For the splices between nano-engineered fibers,the average splice loss is 0.029 dB. For the splices betweennano-engineered and standard single-mode fibers, the averagesplice loss is 0.033 dB. Similar splice loss distributions wereobtained at 1550 nm with the average splice losses similar orslightly lower than the values at 1310 nm. These results aresimilar to standard single-mode fibers, showing no issues forsplicing these new bend insensitive fibers.

Finally, we tested cabled nano-engineered fibers under severedeployment conditions for FTTH applications. The test condi-tions are as follows: corner bends bends with 2 kg

Fig. 8. Splice losses for nano-engineered fiber to nano-engineered fiber at 1310nm.

Fig. 9. Cabled fiber optical attenuation increases at 1550 nm in typical FTTHinstallations.

load wraps at 10 mm diameter staples cornerbend bend with 14 kg load wraps at 10 mm diameter+ 50 staples flat staples. For comparison, a trench fiberwas tested under the same conditions. Fig. 9 plots the attenu-ation increases at 1550 nm for the two fibers. The trench fiberhas a total attenuation increase of almost 2.5 dB. On the otherhand, the total attenuation of nano-engineered fiber is about0.25 dB, which is only one tenth of total attenuation of the trenchfiber. This test demonstrates clearly the advantages of our newbend-insensitive fiber for FTTH deployments.

IV. CONCLUSION

We have proposed a new nanoStructures technology formaking bend insensitive fibers. The new technology is compat-ible with the OVD process and suitable for large scale produc-tion. Using this technology, standard compliant single-modefibers with record low bending loss are demonstrated. Theexcellent bending performance of new nano-engineered fibers,plus their ease of manufacturing and standards compliance,make this fiber particularly well suited to the demanding in-stallation requirements of FTTH networks and makes them thebest choice for such applications.

LI et al.: ULTRA-LOW BENDING LOSS SINGLE-MODE FIBER FOR FTTH 381

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Ming-Jun Li (M’93) received the B.Sc. degree inapplied physics from the Beijing Institute of Tech-nology, Beijing, China, in 1983, the M.Sc. degreein optics and signal processing from University ofFranche-Comté, Besancon, France, in 1985, and thePh.D. degree in physics from University of Nice,Nice, France, in 1988.

From 1989 to 1990, he was a Postdoctoral Fellowwith the Integrated Optics Laboratory, Ecole Poly-technique de Montreal, Montreal, QC, Canada, wherehe worked on waveguide devices such as couplers,

waveguide gratings, and rare earth doped waveguides. From 1991 to 1994, hewas with Nortel Optical Cable Division, Saskatoon, SK, Canada, where he wasa Research Scientist working on designs and process developments for trans-mission fibers and specialty fibers. Since he joined Corning, Inc., Corning, NY,in 1994, his research work has been focused on the fields of optical fibers andoptical networks and systems. He was a key contributor to new fiber develop-ments for long haul and submarine transmissions including the LEAF® fiber,an award-winning product. He made significant contributions to the designsand process improvements for producing ultra-low polarization mode disper-sion (PMD) fibers. He was a co-inventor of the nanoStructures™ technologyfor making fibers and ClearCurve™ optical fiber. He also worked on photonicscrystal fibers and photonics bang-gap fibers as well as specialty fibers such asdispersion compensation fibers, nonlinear fibers, single polarization fibers and

high power laser fibers. His research on optical protection demonstrated feasi-bility of transparent optical protection ring architectures and functionalities. Heis currently a Corning Research Fellow, where his research work is related tonew fiber designs and applications. He holds 42 U.S. patents and has published2 book chapters and authored and coauthored over 120 technical papers in jour-nals and conferences.

Dr. Li received the 1998 French National Prize on Guidedwave Optics for hiswork on Cerenkov second harmonic generation. He also received 2005 StookeyAward for exploratory research at Corning Incorporated. He is a fellow of Op-tical Society of America and a member of the IEEE Lasers and Electro-Op-tics Society. He has served as Associate Editor for the IEEE/OSA JOURNAL

OF LIGHTWAVE TECHNOLOGY (1999–2005), Chair for APOC Subcommittee 1(2007-present), Technical Committee Member for OFC (2004–2007), LEOSwinter topic meeting, APOC (2004–2006), CLEO (2007-Present), ITCom Tech-nical Committee Member (2002–2006).

Pushkar Tandon received the B.Tech. degree inchemical engineering from the Indian Institute ofTechnology, Delhi, India, in 1990, and the Ph.D.degree, also in chemical engineering, from YaleUniversity, New Haven, CT, in 1995.

After completing his post-doctoral research at theInstitute of Medicine and Engineering, Universityof Pennsylvania, Pittsburgh, he joined CorningInc., Corning, NY, in 1998, where he currently isa Senior Research Associate. His work at Corninghas resulted in significant new process and product

development which has been commercialized in the manufacturing of opticalfibers, diesel particulate filters, liquid crystal display glass sheets and specialityglasses. He has authored 38 archival journal publications and 30 conferencepresentations, holds 7 patents, with 34 other patent applications pending.

Dr. Tandon most recent contribution was as co-inventor of Corning®

ClearCurve™ optical fiber which was listed as one of Time magazine’s “BestInventions of the Year” for 2007. He was the receipient of the Corning’sOutstanding Publication Award in 2005. He also serves as a reviewer for anumber of leading journals in the area of chemical and glass/ceramic sciences.

Dana C. Bookbinder received a Bachelor of Sci-ence in chemistry from Northern Illinois Universityin 1978; he was a Dreyfus summer scholar at theUniversity of Chicago in 1977 and received a Ph.D.in chemistry from the Massachusetts Institute ofTechnology in 1982 under the direction of MarkWrighton. Dr. Bookbinder joined Corning in 1991after a nine-year career with General Electric wherehe co-invented a chain terminator for Lexan®

EXL polymer that resulted in the resin used forcompact discs. During his career at Corning, Dr.

Bookbinder’s most significant inventions have been in the areas of OpticalWaveguide inorganic compositions, process technology and surface coatingsSpecialty Materials fused silica compositions and processes, and Life Sciencespolymer surface chemistry and products. His most recent contribution was asco-inventor of Corning™ ClearCurve™ optical fiber which was listed as oneof Time magazine’s “Best Inventions of the Year” for 2007. Dr. Bookbinder’ssuccess has come from working across Research, Development and Manu-facturing groups and implementing technology into commercialization. Theseefforts resulted in the generation of a significant number of new products andrevenue. Dr. Bookbinder was the 1999 recipient of the Stookey Award forExploratory Research and was appointed to the position of Corporate Fellowin 2007. He has been granted more than 40 patents and has over 30 additionalpatents pending.

Scott Bickham received a B.S. in honors physics from Purdue University in1988 and a Ph.D. in condensed matter physics from Cornell University in 1995under the direction of Al Sievers. He was an NRC Research Associate at theNaval Research Laboratory and a Director’s Fellow at Los Alamos NationalLaboratory before joining Corning in 1999. He is currently a DevelopmentAssociate for Corning Optical Fiber, where he has contributed to the designand development of several products, including ClearCurve™, NexCor®

SMF-28eXB™ and Vascade® R1000 fibers. Scott has been granted 29 U.S.patents and has co-authored 18 publications related to optical fiber design andapplications.

382 JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 27, NO. 3, FEBRUARY 1, 2009

Daniel A. Nolan received the Ph.D. degree in physicsfrom the Pennsylvania State University in 1974. Hisresearch interests at that time were in the area of sur-face physics, in particular the adsorption of particleson metallic surfaces.

He joined Corning Inc. in 1974, where he iscurrently a Research Fellow in the Optics and Pho-tonics Directorate. In his initial years with Corninghe investigated the formation of color centers andthe photo kinetic processes in photo chromic andpolarizing glasses. This research contributed to the

introduction of Corning’s Polarcor polarizing glass. He authored a number ofpapers on these subjects in the Journal of Solids, the Journal of the OpticalSociety of America, the Journal of the American Ceramic Society and PhysicsReview. Over the last two decades, he has been involved in the research ofoptical fiber, fiber-optic components and polarization and nonlinear optics.His research activities have included the propagation of light in both singlemode and multimode fibers, nonlinear effects in fibers, fiber-optic sensors, andplanar and fiber-based passive components for local area networks. He wasresponsible for Corning Research activities in fiber-based passive componentsfrom 1984 to 1992. During this period, a number of important components wereinvestigated and transferred to development, including splitters, taps, WDMs,VOAs, switches, 1xn devices and amplifier components. Also during this timeperiod, Corning’s MultiCladTM coupler was introduced. These devices are

used throughout the world and almost exclusively in all undersea fiber opticamplified systems.

Dr. Nolan is a Fellow of the Optical Society of America. He has presentedinvited papers on passive components at the Optical Fiber Conference (OFC)(1991–1993) and has taught a course on Passive Components at this confer-ence (1993–1994). He has been a member of committees for important fiber-optic related conferences, OFC (91–93), IPR (Integrated Photonics Research)(1992–1994), and CLEO (1989–1990, 2000–2003) and the European Confer-ence on Optical Communications (2000–2003). He was an Associate Editor ofIEEE PHOTONIC TECHNOLOGY LETTERS (1990–1995) and has been associateeditor of the publication entitled Fiber and Integrated Optics (1991–1993). Heis on the Steering Committee for the OSA/IEEE Journal of Lightwave Tech-nology. He has published many articles on fibers and on integrated optics inOptics Letters, the IEEE/OSA JOURNAL OF LIGHTWAVE TECHNOLOGY and otherIEEE and OSA publications He has published five books on the subject of op-tical fiber and optical components. His book ‘WDM Components (OSA, 1999)was a best seller. He received Corning’s “Outstanding Publication” award in1989 and Corning’s prestigious Stookey for Exploratory Research in 1995. Hereceived an Outstanding Alumni award from the College of Science at PennState in 2001 for contributions to the field of Optical Communications. He haspresented numerous papers at OFC, IPR and ECOC (the European Conferenceon Optical Communication). He holds 63 U.S. patents and received an IR100award for the invention of infrared polarizing glass, Polarcor™.

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