WaveguideOptics-上海交通大学.ppt

Harmonic electromagnetic field * Helmholtz equation Maxwell equation Longitudinal field and transverse field * E=exEx+ eyEy+ezEz, H=exHx+eyHy+ezHz E=Et+ ezEz H=Ht+ezHz One-dimensional planar optical waveguide and Wave optics description Field division and classification of modes uniformity and symmetry principle of superposition * TE Mode TM Mode confinement layer waveguide layer confinement layer n3 n1 n2 x y z h * Maxwell Equation In rectangular coordinate system TE TM * Field equation Mode solution guided mode condition ?：衰减系数 Thank You！ * * * * * * * * * 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. * Optical fibers: new generation of transmission medium The loss of current production (silica single mode fiber) can be reduced to 0.20 dB/km (wavelength of 1.55 μm). The lab records is as low as 0.151dB/km. （95.5% after 1km, 1% after 100km) The silica optical fiber became the new generation of transmission medium due to its wide band, low dispersion, high tensile strength, strong anti-jamming, resource-rich etc. Novel optical fibers: Erbium-doped optical fiber, Dispersion compensation fiber, Photonic crystal fiber… * 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. * Developing trends multimode fiber ? single mode fiber short wavelength 0.8μm ? long wavelength 1.31 μm, 1.55 μm