Open access

Introductory Chapter: Electromagnetic Propagation and Waveguides in Photonics and Microwave Engineering

Written By

Patrick Steglich

Published: 21 October 2020

DOI: 10.5772/intechopen.93419

From the Edited Volume

Electromagnetic Propagation and Waveguides in Photonics and Microwave Engineering

Edited by Patrick Steglich

Chapter metrics overview

558 Chapter Downloads

View Full Metrics

1. Introduction

Waves can propagate as spherical waves in open space. In this case, the power of the wave decreases with the distance from the source as the square of the distance. In contrast, a waveguide can confine the propagating wave in such a way that the wave propagates only in one dimension. Assuming ideal conditions, the wave is not losing power while it propagates inside the waveguide.

Waveguides play a major role for applications in communications and sensing technologies. The theoretical understanding and practical investments are crucial to develop future innovations.

In photonics, two major types of waveguides can be distinguished, namely optical fibers and integrated waveguides. Waveguides in photonics operate typically in the visible and infrared light spectra.

Optical fibers are used for data transmission, as fiber lasers, for flexible transmission of laser radiation or for lighting, for sensor applications or decoration purposes [1]. The main application of optical fibers, however, is their use in telecommunication systems, making our daily life easier by a fast internet connection [2]. Other important technical applications of optical fibers are lasers [3], interferometers [4, 5], amplifier [6], and sensors [7]. The latter is important since it allows the detection of magnetic fields [8], humidity [9], temperature [10], and biological molecules [11, 12]. Massive research investments in the field of optical fibers [13, 14, 15] have led to novel applications. One important example is the use of optical for endoscopic applications [16, 17]. Also the fiber core has been modified (Figure 1), so that novel applications such as gas sensor can be addressed.

Figure 1.

Optical fiber with simple homogeneous fiber core (a) and with photonic crystals, also known as hollow core fiber (b).

Integrated waveguides confine light in submicrometer structures on chip. Such waveguide structures are made either by doping the substrate material or by structuring it with etching procedures. Mostly, such waveguides are formed by patterning semiconductor materials like silicon, which is known as photonic integrated circuit technology [18]. The dimension of those waveguides in single mode operation is typically about 220 nm in width and 500 nm in height. Figure 2 shows three different types of waveguides based on silicon.

The main applications are electro-optical modulators in telecommunications [19] and integrated sensors [20, 21] for point-of-care-diagnostics, environmental monitoring, or food analysis [22, 23]. A relatively novel approach is the silicon-organic hybrid technology [24, 25, 26]. Here, the silicon-based waveguide is covered with organic materials [27, 28, 29] leading to highly energy-efficient modulators [30] with large 3-dB modulation bandwidth [31]. This technology mainly uses slot waveguides because they provide a large overlap of optical and electrical field. Novel waveguide structures like slot waveguides [32, 33, 34, 35] allow also the use of the quadratic electro-optical effect [36, 37, 38] and the electric field-induced linear electro-optical effect [39, 40]. This gives perspective to novel modulation schemes and applications in programmable photonics.

Before optical waveguides were integrated into semiconductor chips, metal lines were already implemented several years ago, forming microwave waveguides [41]. These waveguides are used in microwave engineering. The short wavelengths distinguish microwave engineering from electronics. One particular example of microwave waveguides is the so called hollow metal pipe. A hollow metal pipe is a waveguide for electromagnetic waves, typically in the frequency range from 1 to 200 GHz [42]. Such waveguides are metal tubes with a generally rectangular, circular, or elliptical cross section. They have been studied and applied to industrial applications since almost one century [43]. New fabrication methods like 3D printing led to a renewed attention on this type of waveguide [44]. For example, practical work on microwaves concentrated on the low frequency end of the radio spectrum because it allows a long-range communication [45].

Figure 2.

Integrated optical waveguides based on silicon used in photonic integrated circuits.


  1. 1. Steglich P, De Matteis F. Introductory chapter: Fiber optics. In: Fiber Optics-from Fundamentals to Industrial Applications. Rijeka: IntechOpen; 2019
  2. 2. Steglich P, Heise K. Photonik einfach erklärt: Wie Licht die Industrie revolutioniert. Heidelberg: Springer-Verlag; 2019
  3. 3. Duval S et al. Femtosecond fiber lasers reach the mid-infrared. Optica. 2015;2(7):623-626
  4. 4. Zhou J et al. Intensity modulated refractive index sensor based on optical fiber Michelson interferometer. Sensors and Actuators B: Chemical. 2015;208:315-319
  5. 5. Lee, Ha B, et al. Interferometric fiber optic sensors. Sensors. 2012;12.3:2467-2486
  6. 6. Firstov SV et al. A 23-dB bismuth-doped optical fiber amplifier for a 1700-nm band. Scientific Reports. 2016;6:28939
  7. 7. Hernaez M, Zamarreño CR, Melendi-Espina S, Bird LR, Mayes AG, Arregui FJ. Optical fibre sensors using graphene-based materials: A review. Sensors. 2017;17:155
  8. 8. Zheng Y et al. Optical fiber magnetic field sensor based on magnetic fluid and microfiber mode interferometer. Optics Communications. 2015;336:5-8
  9. 9. Gao R et al. Humidity sensor based on power leakage at resonance wavelengths of a hollow core fiber coated with reduced graphene oxide. Sensors and Actuators B: Chemical. 2016;222:618-624
  10. 10. Hernández-Romano I et al. Optical fiber temperature sensor based on a microcavity with polymer overlay. Optics Express. 2016;24(5):5654-5661
  11. 11. Ricciardi A et al. Lab-on-fiber technology: A new vision for chemical and biological sensing. Analyst. 2015;140(24):8068-8079
  12. 12. Liu X, Zhang Y. Optical fiber probe-based manipulation of cells. In: Fiber Optics - from Fundamentals to Industrial Applications, Patrick Steglich and Fabio De Matteis. Rijeka: IntechOpen; 2018
  13. 13. Shuto Y. Cavity generation modeling of fiber fuse in single-mode optical fibers. In: Fiber Optics—From Fundamentals to Industrial Applications, Patrick Steglich and Fabio De Matteis. Rijeka: IntechOpen; 2018
  14. 14. Michel YP, Lucci M, Casalboni M, Steglich P, Schrader S. Mechanical characterisation of the four most used coating materials for optical fibres. In: 2015 International Conference on Photonics, Optics and Laser Technology (PHOTOPTICS). Berlin: IEEE; 2015. pp. 91-95
  15. 15. Bahl M. Structured light fields in optical fibers. In: Fiber Optics—From Fundamentals to Industrial Applications, Patrick Steglich and Fabio De Matteis. Rijeka: IntechOpen; 2019
  16. 16. Pulwer S, Fiebelkorn R, Zesch C, Steglich P, Villringer C, Villasmunta F, et al. Endoscopic orientation by multimodal data fusion. In: Proceeding SPIE 10931, MOEMS and Miniaturized Systems XVIII, 1093114. 4 March 2019. DOI: 10.1117/12.2508470
  17. 17. Pulwer s, Steglich P, Villringer C, Bauer J, Burger M, Franz M, et al. Triangulation-based 3D surveying borescope. In: Proceeding SPIE 9890, Optical Micro- and Nanometrology VI, 989009. 26 April 2016. DOI: 10.1117/12.2225203
  18. 18. Mai A, Steglich P, Mai C, Simon S, Scholz R. Electronic-photonic wafer-level technologies for fast prototyping and application specific solutions. In: 2019 PhotonIcs & Electromagnetics Research Symposium—Spring (PIERS-Spring). Rome, Italy: IEEE; 2019. pp. 249-255
  19. 19. Alimonti G et al. Use of silicon photonics wavelength multiplexing techniques for fast parallel readout in high energy physics. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 2019;936:601-603
  20. 20. Steglich P et al. Hybrid-waveguide ring resonator for biochemical sensing. IEEE Sensors Journal. 2017;17(15):4781-4790
  21. 21. Mai A, Bondarenko S, Mai C, Steglich P. Photonic thermal sensor integration towards electronic-photonic-IC technologies. In: ESSDERC 2019—49th European Solid-State Device Research Conference (ESSDERC). Cracow, Poland: IEEE; 2019. pp. 254-257
  22. 22. Steglich P, Villringer C, Pulwer S, Casalboni M, Schrader S. Design optimization of silicon-on-insulator slot-waveguides for electro-optical modulators and biosensors. In: Ribeiro P, Raposo M, editors. Photoptics 2015. Springer Proceedings in Physics. Vol. 181. Cham: Springer; 2016
  23. 23. Steglich P, Hülsemann M, Dietzel B, Mai A. Optical biosensors based on silicon-on-insulator ring resonators: A review. Molecules. 2019;24:519
  24. 24. Steglich P, Mai C, Mai A. Silicon-organic hybrid photonic devices in a photonic integrated circuit technology. ECS Journal of Solid State Science and Technology. 2019;8(11):Q217
  25. 25. Mai C, Steglich P, Mai A. Adjustment of the BEOL for back side module integration on wafer level in a silicon photonic technology. In: MikroSystemTechnik 2019. Berlin, Germany: Congress; 2019. pp. 1-4
  26. 26. Steglich P et al. (keynote) silicon-organic hybrid photonics: Integration of electro-optical polymers in a photonic integrated circuit technology. ECS Transactions. 2019;92.4:187
  27. 27. Steglich P, Mai C, Stolarek D, Lischke S, Kupijai S, Villringer C, et al. Partially slotted silicon ring resonator covered with electro-optical polymer. In: Proceeding SPIE 9891, Silicon Photonics and Photonic Integrated Circuits V, 98910R. 13 May 2016. DOI: 10.1117/12.2217725
  28. 28. Steglich P et al. Functionalized materials for integrated photonics: Hybrid integration of organic materials in silicon-based photonic integrated circuits for advanced optical modulators and light-sources. In: 2019 PhotonIcs & Electromagnetics Research Symposium—Spring (PIERS-Spring). Rome, Italy: IEEE; 2019. pp. 3019-3027
  29. 29. Steglich P et al. Novel ring resonator combining strong field confinement with high optical quality factor. IEEE Photonics Technology Letters. 2015;27(20):2197-2200
  30. 30. Koeber S et al. Femtojoule electro-optic modulation using a silicon–organic hybrid device. Light: Science & Applications. 2015;4(2):e255-e255
  31. 31. Alloatti L et al. 100 GHz silicon–organic hybrid modulator. Light: Science & Applications. 2014;3(5):e173-e173
  32. 32. Steglich P, You KY. Silicon-on-insulator slot waveguides: Theory and applications in electro-optics and optical sensing. In: Emerging Waveguide Technology. Rijeka: IntechOpen; 2018. pp. 187-210
  33. 33. Steglich P, Villringer C, Dümecke S, Michel YP, Casalboni M, Schrader S. Silicon-on-insulator slot-waveguide design trade-offs. In: 2015 International Conference on Photonics, Optics and Laser Technology (PHOTOPTICS). Berlin: IEEE; 2015. pp. 47-52
  34. 34. Bondarenko S, Villringer C, Steglich P. Comparative study of nano-slot silicon waveguides covered by dye doped and undoped polymer cladding. Applied Sciences. 2019;9:89
  35. 35. Bondarenko S, Steglich P, Schrader S, Mai A. Simulation study of released silicon-on-insulator slot waveguides in a photonic integrated circuit technology. In: 2019 PhotonIcs & Electromagnetics Research Symposium—Spring (PIERS-Spring). Rome, Italy: IEEE; 2019. pp. 3334-3337. DOI: 10.1109/PIERS-Spring46901.2019.9017643
  36. 36. Steglich P, Mai C, Villringer C, Pulwer S, Casalboni M, Schrader S, et al. Quadratic electro-optic effect in silicon-organic hybrid slot-waveguides. Optics Letters. 2018;43:3598-3601
  37. 37. Steglich P et al. On-chip dispersion measurement of the quadratic electro-optic effect in nonlinear optical polymers using a photonic integrated circuit technology. IEEE Photonics Journal. June 2019;11(3):1-10
  38. 38. Steglich P et al. Quadratic electro-optical silicon-organic hybrid RF modulator in a photonic integrated circuit technology. In: 2018 IEEE International Electron Devices Meeting (IEDM). San Francisco, CA: IEEE; 2018. pp. 23.3.1-23.3.4
  39. 39. Steglich P et al. Electric field-induced linear electro-optic effect observed in silicon-organic hybrid ring resonator. IEEE Photonics Technology Letters. 2020;32(9):526-529
  40. 40. Steglich P et al. Direct observation and simultaneous use of linear and quadratic electro-optical effects. Journal of Physics D: Applied Physics. 2020;53(12):125106
  41. 41. Davidson DB. Computational Electromagnetics for RF and Microwave Engineering. Cambridge: Cambridge University Press; 2010
  42. 42. Pozar DM. Microwave Engineering. 4th Ed. New Jersey: Wiley; 2011
  43. 43. Chu LJ. Electromagnetic waves in elliptic hollow pipes of metal. Journal of Applied Physics. 1938;9(9):583-591
  44. 44. D’Auria M, Otter WJ, Hazell J, Gillatt BT, Long-Collins C, Ridler NM, et al. 3-D printed metal-pipe rectangular waveguides. IEEE Transactions on Components, Packaging and Manufacturing Technology. 2015;5(9):1339-1349
  45. 45. Packard KS. The origin of waveguides: A case of multiple rediscovery. IEEE Transactions on Microwave Theory and Techniques. 1984;32(9):961-969

Written By

Patrick Steglich

Published: 21 October 2020