![]() The Cd1-xMnxTe waveguide was grown by molecular beam epitaxy (MBE) on GaAs (001) substrate. Otherwise, the high density of dislocation in Cd1-xMnxTe film causes high optical loss in Cd1-xMnxTe waveguide (Zaets et al.,1997) and low value of Faraday rotation. The growth conditions of Cd1-xMnxTe on GaAs substrate should be well optimized. The Cd1-xMnxTe has about 12% lattice mismatch with GaAs. TM-TE mode conversion ratio in Cd1-xMnxTe waveguide at λ=730 nm Bulk optical isolators using these materials are now commercially available.įig.3. For longer-wavelength (λ=800-1600 nm) optoelectronic devices, Cd1-x-yMnxHgyTe can be used. Furthermore, the tunability of its absorption edge from 1.56 to 2.1 eV with Mn concentration makes the Cd1-xMnxTe magneto-optical waveguide compatible with (Al,Ga,In)P:GaAs optoelectronic devices operating in the wavelength range of 600-800 nm. Cd1-xMnxTe also exhibits a huge Faraday effect (its Verdet constant is typically 50-200 deg/cm/kG) near its absorption edge because of the anomalously strong exchange interaction between the sp-band electrons and the localized d-electrons of Mn2+. Cd1-xMnxTe shares the zinc-blende crystal structure with the typical semiconductor optoelectronic materials such as GaAs and InP thus its film can be grown directly on GaAs and InP substrates. Paramagnetic semiconductor Cd1-xMnxTe is promising as a magneto-optical material for integrated optical isolators and circulators. Lower diagrams show polarization in backward direction. Upper diagrams show polarization in forward direction. The Faraday rotator is placed between entrance polarizer (left side) and exit polarizer (right side). But the garnet-made isolators have not been monolithically integrated with semiconductor optoelectronic devices, because these oxide crystals can not be grown on semiconductor substrates.įig.1 Design of free-space optical isolator. Waveguide optical isolator based on the garnet film has been reported (Ando et al.,1988). Because most of the active optical elements (such as the laser diode, optical amplifier, modulator, and optical gate) are produced on GaAs or InP substrates, it is desirable to integrate monolithically all optical components on these types of substrate, but integration of the isolator is a difficult task. In present optical networks, ferrimagnetic garnet oxide crystals such as Y3Fe5O12 (YIG) and (GdBi)3Fe5Ob are used as magneto-optical materials for discrete optical isolators. At the entrance polarizer, the polarization is 90 degree to the polarizer axis and the light is fully blocked. In backward direction, the direction of polarization rotation is opposite to that in forward direction due the non-reciprocal nature of the magneto-optical effect. Therefore, the light can pass through the isolator in forward direction. In forward direction the polarization of light is 45 degree rotated by the Faraday rotator to be along the axis of the exit polarizer. The angle between axes of entrance polarizer and exit polarizer is 45 degree degrees. The conventional bulk-type optical isolator consists of a 45-degree Faraday rotator placed between two polarizers. These values are comparable or better to that of commercial discrete isolators. ![]() For (Cd,Mn)Te waveguide with (Cd,Zn)Te grown on GaAs substrate we achieved a high Faraday rotation of 2000 deg/cm, a high isolation ratio of 27 dB, a low optical loss of 0.5 dB/cm, and a high magneto-optical figure-of-merit of 2000 deg/dB/kG in a wide 25-nm wavelength range. The (Cd,Mn)Te exhibits a huge Faraday effect and can be grown on a semiconductor substrate. We proposed to use (Cd,Mn)Te as a magneto-optical material for such isolator. The isolator for a monolithic integrationĪt present, there is a significant commercial demand for optical isolator and circulator, which could be integrated into photonic integrated circuit. Enhancement of Transverse MO for plasmonsĬdMnTe integrated optical isolator.Optical excitation of spin-polarized electrons utilizing transverse MO.Calculations of transverse MO effect in the case of multilayer structure.Two contributions to transverse MO effect.Experimental observation of transverse MO effect.Voltage- controlled magnetism (VCMA effect).Perpendicular magnetic anisotropy (PMA).Conduction in the vicinity of Interface.My Research and Inventions click here to see all content or button bellow for specific topic
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