Waveguide OpticsTeacher : Lilin YiEmail : lilinyi@sjtu.edu.cnOffice : SEIEE buildings 5-517Tel ：34204596

http://front.sjtu.edu.cn/~llyi/waveguide

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State Key Lab of Advanced Optical Communication System and Networks

Self-introduction

• 2012.6-现在 上海交通大学电子工程系 博士生导师

• 2010.12-现在 上海交通大学电子工程系 副教授

• 2010.4-现在 上海交通大学电子工程系 讲师/硕士生导师

• 2008.5-2010.3 Oclaro(原Avanex) Corporation 产品开发经理/高级工程师/光学工程师

• 2006.10-2008.3 法国国立高等电信学校（ENST） 博士

• 2004.9-2008.4 上海交通大学电子工程系 博士

• 2002.9-2005.3 上海交通大学物理系光学专业 硕士

• 1998.9-2002.7 上海交通大学物理系 学士

简历

• 上海市教委“晨光”学者• 全国优秀博士论文，2010• 上海市优秀博士论文，2009• Oclaro/Avanex杰出员工奖，2009/2008• SPIE Asia Pacific Optical Communications Conference，Best Student Paper Awards (亚太光通信国际会议SPIE最佳学生论文奖), 2007

• 上海市优秀硕士论文, 2006• 国家优秀奖学金、3M创新奖学奖、中科院奖学金，2005• 上海市三好学生, 2004

荣誉及奖励

• 共发表学术论文68篇(SCI论文35篇)，其中第一作者论文24篇(包括SCI论文15篇、国际会议

论文16篇),发表论文被SCI他引250次，以下列出部分代表性论文：• Lilin Yi, Weisheng Hu, Yi Dong, Yaohui Jin, Wei Guo, and Weiqiang Sun, “A polarization-independent subnanosecond 2×2 multicast-capable optical switch using a

sagnac interferometer,” IEEE Photon. Technol. Lett. vol. 20, pp. 539-541, 2008.• Lilin Yi, Yves Jaouen, Weisheng Hu, Yikai Su and Sébastien Bigo, “Improved slow-light performance of 10 Gb/s NRZ, PSBT and DPSK signals in fiber broadband SBS,”

Optics Express，vol. 15, no. 25, pp. 16972-16979, 2007.• Lilin Yi, Yves Jaouen, Weisheng Hu, Junhe Zhou, Yikai Su and Erwan Pincemin, “Simultaneous demodulation and tunable-delay of DPSK signals using SBS-based

optical filtering in fiber,” Optics Letters, vol. 32, no. 21, pp. 3182-3184, 2007.• Lilin Yi, Li Zhan, Weisheng Hu, Yuxing Xia, “Delay of broadband signals using slow light in stimulated Brillouin scattering with phase-modulated pump,” IEEE Photon.

Technol. Lett. vol. 19, no. 8, pp. 619-621, 2007.• Lilin Yi, Weisheng Hu, Yikai Su, Mingyi Gao, and Lufeng Leng, “Design and system demonstration of a tunable slow-light delay line based on fiber parametric process,”

IEEE Photon. Technol. Lett. vol. 18, no. 24, pp. 2575-2577, 2006.

代表性研究成果

Research Fields

optical signal processing

PON

Microwave Photonics

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Syllabus(flexible)Chapter 1 Introduction

• § 1-1 History and Present State• § 1-2 Essential Questions in Waveguide Optics• § 1-3 Basic Research Method of Waveguide Optics

Chapter 2 Analytical method• § 2-1 Geometrical Optics Method• § 2-2 Electrodynamics Fundamentals • § 2-3 Wave Optics Method

Chapter 3 Fiber Mode Theory• § 3-1 Modes in The Step Refractive Index Fiber • § 3-2 Linearly Polarized Modes in The Weak-guidance Optical Fiber • § 3-3 Universal Properties of Modes in Waveguide • § 3-4 Perturbation Method in Transversely Non-uniform Waveguide• § 3-5 Vertically Non-uniform Waveguide and The Coupled Mode Equations

Chapter 4 Single Mode Fiber Theory• § 4-1 The Step-index Monomode Fiber • § 4-2 Gaussian Fitting Method for SMF and Mode Field Diameter• § 4-3 Approximate Solution of SMF• § 4-4 Main Types of SMF• § 4-5 Polarization Character of SMF• § 4-6 Production of SMF and Fiber Optic Cable

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Chapter 5 Signal Degrade in Fiber• § 5-1 Attenuation• § 5-2 Chromatic Dispersion• § 5-3 Nonlinearity

Chapter 6 Semiconductor Laser • § 6-1 Physical Basis of Semiconductor Laser • § 6-2 Structure of Semiconductor Laser • § 6-3 Performance Characteristic of Semiconductor Laser

Chapter 7 Photodetectors and Optical Receivers• § 7-1 Photodetectors • § 7-2 Characteristic Index of Photodetectors• § 7-3 Optical Receivers

Chapter 8 Modulation Formats• § 8-1 General Concepts of Optical Modulation• § 8-2 electro-optic effect• § 8-3 Electro-optical Modulator• § 8-4 Modulation Format

Chapter 9 High bit rate transponder• §9-1 Standard evolution• §9-2 100G commercial transponder• §9-3 Technical trend for 400G and 1T

Chapter 10 Fiber Amplifier Design• §10-1 EDFA Design• §10-2 Raman Amplifier Design

Chapter 11 EDFA design process

Chapter 12 Semiconductor Optical Amplifier• §12-1 SOA in Transmission• §12-2 SOA in Signal Processing

Chapter 13 PON• §13-1 EPON/GPON (TDMA)• §13-2 WDM-PON• §13-3 CDMA• §13-4 OFDM-PON

Chapter 14 Optical Switching• §14-1 Forms of Optical Switching• §14-2 Key Technology of OPS• §14-3 Optical Buffer

Seminar

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References

《光波导理论与技术》李玉权等人民邮电出版社

《导波光学》范崇澄 北京理工大学出版社

《非线性光纤光学》(Nonlinear Fiber Optics)，G.

P. Agrawal,天津大学出版社，

《光纤通信》(Fiber Optics Communications)，

Joseph C. Palais, 电子工业出版社

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Chapter 1

Introduction

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10-1

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10-6

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ELF VF VLF LF MF HF VHF UHF SHF EHF

free space wavelength(m)

Frequency(Hz)

electricity

phone

wireless

TV

microwave infrared visible light

twisted pair

coaxial cable

Fibersatellite

/microwave

AM FM

Fiber

Wavelength range： 0.1μm～10μm(300THz~30THz)

1 History and Present State

An ancient optical system: smoke signals on the beacon tower

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Modern communication demonstration for the first time : telephone

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In 1880 Bell invented the “photophone” after the telephone.The voice signals propagate for 200m.

The beam varies with the vibrations of the speaking trumpet. This process is called modulation.Bell treated the photophone as the most important invention in his lifetime, but it has not been used due to the light source and transmission medium problems.

Research focus on underground: underground communication experiments emerged such as reflection waveguide and lens waveguide, but the prices are high. Besides, adjustment and maintenance are difficult.

Underground optical communication

Difficulties in optical communication：1. No suitable light sources

• General light sources has bad directivity and coherency, similar to the noise and cannot be modulated.

2. No suitable transmission medium• Optical frequency is extremely high and cannot go

through obstacles easily. (low loss materials are required.)

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The invention of laser

In 1960 Maiman invented the ruby laser

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The laser has good mono-chromaticity, directivity,coherency, high brightness, high powerThe invention and application make opticalcommunication into a new stage

In 1870, British physicist Tyndall

sunlight bends with the water flownwater > nair light occurs total reflection

The prototype of the optical fiber

In 1953, Dr. Kapany of the London Institute invented glassoptical fiber: core + cladding (ncore>ncladding) – fibers

In 1960, the lowest fiber loss was 1000 dB/km, and it canonly be used in medical treatment, such as endoscope

The principle of total reflection in the glass hasbeen used at short distance (m) transmission.Circular cross-section dielectric opticalwaveguide is researched theoretically andexperimentally by E.Snitzer in 1961.Until the mid-60s, the best transmission loss ofoptical glass is still as high as 1000 dB/km.Without reliable and low-loss transmissionmedium, optical communication research wasinto a low ebb at that point.

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The birth of optical fiber

In seemingly hopeless situations, Charles Kaoin 1966 published an paper which wassubsequently proven to be epoch-making. Inthis paper, Kao foresaw the transmission lossmay be less than 20 dB/km by using opticalfibers made of high-purity quartz glass withcladding material. (95.5% after 10m，1% after1km)

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In 1966, Kao and C.A.Hockham published the paper on the newconcept of transmission media “Dielectric-fiber surface waveguidesfor optical frequency”. They pointed out that raw material purificationis the right approach to producing suitable low-loss optical fiber forlong distance communication.It lay the foundation for modern optical communication--fiber-opticcommunication.

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Charles Kao (left) awarded a medal by the IEE in the UK(1998).

In 1970, come into being!!!1970 Corning Glass Company first developed fibers with attenuation of 20 dB/km. Optical fiber communication begun!

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Basic idea : low loss• (1) Dope oxides into pure quartz to form the required

refractive index distribution.• (2) Using vapor deposition technique (still in use

today).

The former ensures excellent physical and chemical properties.The latter make the process flexible and help materials “purification” ensuring low loss.

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In 1970,Corning Co.Ltd fabricated the quartz fiber with loss20 dB/km

In 1972,Corning Co.Ltd, ultrapure quartz multimode fiberslowered the loss to 4 dB/km

In 1973,Bell Labs lowered the fiber loss to 2.5 dB/km

In 1974,Bell Labs lowered the loss to 1.1 dB/km

In 1976,NTT company lowered the loss to 0.47 dB/km

Now standard fiber loss at the wave length of 1.55 mm is <0.2 dB/km

Manufacture of low loss fibers

Optical fibers: new generation of transmission mediumThe loss of current production (silica single mode fiber) can bereduced to 0.20 dB/km (wavelength of 1.55 μm). The lab records isas low as 0.151dB/km. （95.5% after 1km, 1% after 100km)The silica optical fiber became the new generation of transmissionmedium due to its wide band, low dispersion, high tensile strength,strong anti-jamming, resource-rich etc.Novel optical fibers: Erbium-doped optical fiber, Dispersioncompensation fiber, Photonic crystal fiber…

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Fiber-optical communication

Another important event in the early 70 is the implementation of continuous operation of semiconductor lasers at room temperature.Optical fiber communication received unprecedented attention. Laboratory research quickly transformed to industrial products which brought about huge social and economic benefits.Fiber optics, integrated Photonics and integrated optoelectronics are the basis of modern optical fiber communication.

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In 1976, the first field test worldwide of practical optical fibercommunication system was done in Atalanta, AmercaIn 1976, experiment of step-index multimode fiber communication systemwith 34 Mb/s in JapanIn 1978, experiment of grading multimode fiber communication systemwith 100 Mb/s in JapanIn 1980, American standardized FT – 3 optical communication systemwas put into commercial useIn 1983, Japan laid long-distance trunk lines of optical cables runningnorth and southIn 1988, America, Japan, England and France built the first submarineoptical cable communication system across the AtlanticIn 1989, built the first submarine optical cable communication systemacross the Pacific

Development of optical fiber communication systems

Worldwide optical communication systems

Developing trendsmultimode fiber single mode fibershort wavelength 0.8μm long wavelength 1.31 μm, 1.55 μm

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Era of optical fiber communications

• 96ch*100Gb/s*10,608km= 108 Gb/s•km• OFC2010-Tyco

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Transmission trend

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Switching

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Optical interconnectsIBM, Intel rack-to-rack, server-to-server, service room to service roomCPU interconnect, Multi-core CPU Silicon PhotonicsPICHybrid Integration

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Photonic integration circuit -PIC

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100Gb/s (10*10Gb/s) capacity line card 10 discrete transceivers vs. WDM system on a chipInP based PIC can integrate active functions (laser, modulator, detector) and passive functions (DWDM, VOA and switch) on a single chip, which benefits the system size, power consumption, reliability and cost.

400Gb/s (10*40Gb/s) PIC – more than 100 devices on a single chip (OFC2008)

PIC – optical router

Hybrid integration

Fiber-optic sensingChanges in environmental factors have an impact on thepropagation characteristics of light in waveguides (intensity, phase,and polarization).Optical waveguide (mainly fiber) sensing devices on：pressure,stress, strain, displacement, velocity, acceleration, turning, liquidlevel, flow rate, flow, temperature, voltage, electric current, electricfield, magnetic field, gamma-ray chemical composition.Some of them have been transferred to the production since the70s.One of the hot spots in waveguide optics because of theimportance of information-access in modern societies.

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References since the 80 'sOptical waveguide theory and calculations：

• 1. A. J. Adams, An Introduction to Optical Waveguides, John Wiley and Sons, New York, 1981. • 2. A. W. Snyder and J. D. Love, Optical Waveguide Theory, Chapman and Hall, London, 1983. • 3. H. A. Haus, Waves and Fields in Optoelectronics, Prentice Hall, 1984. • 4. T. Tamir, Guided-Wave Optoelectronics, 2nd Ed., Springer-Verlag, 1990. • 6. K. Okamoto, Fundamentals of Optical Waveguides, Academic Press, San Diego,2000. • 7. K. Kawano and T. Kitoh, Introduction to Optical Waveguide Analysis, John Wiley & Sons, New

York, 2001.

Fiber nonlinearity: • 1. G. P. Agrawal, Nonlinear Fiber Optics (3rd Ed.), Academic Press, San Diego,2001.• 2. G. P. Agrawal, Applications of Nonlinear Fiber Optics, Academic Press, San Diego, 2001.

Optical fiber communication system: • 1. T. Li(Ed.),Topics in Lightwave Transmission Systems,Academic Press, San Diego,1992. • 2. L. Kazovsky, S. Bennedetto and A. Willner, Optical Fiber Communication Systems, Artech

House, 1996. • 3. I. P. Kaminow and T. L. Koch(Ed.), Optical Fiber Telecommunications (III A,B), Academic

Press, San Diego,1997. • 4. I. P. Kaminow and T. Y.Li(Ed.), Optical Fiber Telecommunications (IV A,B), Academic Press,

San Diego,2002. • 5. 杨祥林，光纤通信系统，国防工业出版社，北京，2000.

EDFA: • 1. E. Desurvire, Erbium-doped Fiber Amplifiers-Princples and Applications, John Wiley and Sons,

New York, 1994. • 2. P. C. Becker, N. A. Olsson and J. R. Simpson, Erbium-doped Fiber Amplifiers-Fundamantals

and Technology, Academic Press, San Diego,1999.

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Main academic publications

• 1. Nature Photonics• 2. Optics Letters • 3. Optics Express• 4. IEEE/OSA Journal of Lightwave Technology • 5. IEEE Photonics Technology Letters • 6. IEEE Journal of Quantum Electronics • 7. IEEE JSTQE • 8. Optics Communications • 9. Electrons Letters• 10. Chinese Optics Letters • 11. 电子学报• 12. 中国激光

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2 Optical Waveguide

Basic structures and modes

The waveguide is infinite in the vertical direction to the section.The refractive index is only the function of the horizontal coordinates.

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If light is confined in waveguides, it is possible to achieve long-distance transmission. This situation is called guided wave mode. conversely, if light is radiated in the horizontal direction, it is called radiation mode.Refraction rule: in cylindrical waveguide structure, light in the transverse direction is always tends to be concentrated in the larger refractive index along the vertical transmission.

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Typesone-dimensional: planar optical waveguide/ thin film optical wave-guidetwo-dimensional: strip optical waveguide/fiberstep index optical waveguide/ graded index optical waveguideRefractive index difference of optical waveguide is generally small, at the 10-2~10-3 level which is favorable for simplifying analysis.Protective coating to improve the mechanical properties

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3 Essential Questions

The distribution of light fields on the cross section of waveguidesThe propagation of light fields along the waveguidesThe coupling between modes when waveguide disturbedAttenuation of signal when travelling along the optical waveguideDistortion of signal when travelling along the optical waveguideNonlinear effects in optical fiberThe polarization of light fields along the waveguideActive optical fiberOptical waveguide excitation

"comprehensive" issue: how to design optical waveguide or related devices to meet a given performance.

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4 Geometrical Optics Method

Geometrical (Ray) Optics MethodRay can represent propagation direction of light and intensity but can not describe field phase and vibration direction (λ→0 and ignoring wave character )main features:

• Waveguide can confine light when the incoming light satisfies the total reflection condition i.e. the angle of incoming light is changeable continuously.

• Light field outside the core was completely ignored when satisfying the total reflection condition .

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5 Waveguide Optics Method

Strictly speaking, optical waveguide problemshould be solved by electromagnetic method.Solve electromagnetic wave equation andlateral boundary conditions to yieldhorizontal distribution (eigenfunctions) andlongitudinal propagation constant (intrinsicvalue)Each solution corresponds to a mode, alsoknown as the mode-field method.

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Solving methodsAnalytical solution of wave equations are often unable to be found. The following two methods are adopted instead:

• Numerical solution: Applicable to many kinds of refractive index distribution. Existing problems: solution accuracy, convergence.

• Approximate analytical solution:Weak-guidance approximation: The refractive index of the core and cladding has little distinction. A particular mode field distribution can be equivalent to a known analytic function.A practical waveguide which has multiple modes can be equivalent to a waveguide which has a known analytical solution.

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Thank You！

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