Fiber Optic Tutorials

This is a continuation from the previous tutorial - magneto-optic recording. It is possible to implement various kinds of guided-wave magneto-optic devices for optical modulation, switching, and many other functions. Nevertheless, there has been very little interest in developing such devices because equal or better performance of the functions provided by such devices can be accomplished by their electro-optic or acousto-optic counterparts. Among devices of equal performance, the magneto-optic ones have certain disadvantages. Magneto-optic waveguides are not compatible with the dielectric and semiconductor waveguides used in most photonic devices because they have to be fabricated with magnetic materials, most commonly...

This is a continuation from the previous tutorial - magneto-optic modulators and sensors. In magneto-optic recording, digitized information stored in a magnetic thin film is read using the magneto-optic Faraday or Kerr effect. There are certain similarities between the principle of magneto-optic recording and that of the magneto-optic spatial light modulator. Indeed, because of its nonvolatility, a magneto-optic spatial light modulator also has the ability to hold digitized information for later access. Reading of the recorded information is performed using the magneto-optic Faraday effect. However, while the application of a magneto-optic spatial light modulator is primarily dynamic information processing, the...

This is a continuation from the previous tutorial - optical isolators and circulators. Polarization and amplitude modulators that are based on the Faraday effect and are driven by currents or magnetic fields can be easily realized. In comparison to the electro-optic polarization and amplitude modulators discussed in previous tutorials, these devices have similar functions but quite different characteristics. The mechanism responsible for magneto-optic polarization modulators is circular birefringence, whereas that for electro-optic polarization modulators is linear birefringence. If the input optical wave is linearly polarized, the output of an ideal magneto-optic polarization modulator is linearly polarized, but hat of an...

This is continuation from the previous tutorial - magneto-optic Kerr effect. In an optical system, reflections and backscattering of light often cause serious problems ranging from noise in the photodetectors to instabilities in the light sources. A feedback, even at an extremely low level, to a laser usually has a significant effect on the laser characteristics. It can change the laser frequency, increase the laser noise, create fluctuations in the laser intensity, lock the laser to a different mode of operation, or drive the laser into instability, even chaos. A feedback to a photodetector or other parts of an optical...

This is a continuation from the previous tutorial - Faraday effect. Reflection of a polarized optical wave from the surface of a material with an internal magnetization or from that of one subject to an external magnetic field results in a change of the polarization state and/or the reflectivity that is dependent on the magnetization or the magnetic field. This phenomenon is known as the magneto-optic Kerr effect. It is totally unrelated to, and should not be confused with, the electro-optic Kerr effect discussed in the electro-optic effect tutorial. The only connection between the two is that both were discovered...