All Optical Switch Research Papers (original) (raw)

We propose an all optical switching scheme based on Raman gain in silicon nanowaveguide suitable for multichannel optical communications. Raman gain is used for amplification of control pulse with higher wavelength which depletes the tuned channel signal. Separation between control and signal pulses should be equal to the Raman shift in silicon. By employing 3 mm channel nanowaveguide we demonstrate a channel attenuation of about 12 dB while the suppression ratio for the first and second neighboring channels are about 1.6 dB and 1 dB, respectively. This scheme can be used as an all optical switch in DWDM networks. Moreover, we demonstrate that the depleted channel can be retrieved by a control pulse with lower wavelength in which the pulse amplifies the channel in contrast to the prior situation.

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- Optical Fiber Communications, Nonlinear Optics, All Optical Switch

Nonlinear optical materials with optimum properties are essential in continuous development of photonic and electro-optical devices, used in optical communications, networking, optical computation for signal processing, and data storage equipments. The changing trend is to use organic materials/dyes that exhibit exceptional nonlinear optical properties instead of conventional materials which have comparatively low nonlinear properties. These organic materials/dyes are easy to prepare in solution or solid form. The resulting organic material has a low dielectric constant, eliminating the need for poling while maintaining the refractive index. However, these organic materials have few of the drawbacks inherent in the processing of comparable inorganic materials like of intense light induced degradation or bleaching and aggregation at higher dye concentration. In order to overcome these drawbacks and for effective use of highly nonlinear dyes, the dye molecules are doped in polymer matrix. This idea of dye-doped polymer material matrix may increase the concentration of absorptive or fluorescence centers as well as the opto-chemical and opto-physical stability. In this paper, we have discussed the strategic advantages of dye-doped polymer nonlinear materials in comparison with organic and inorganic nonlinear materials for optical phase conjugation and all optical switches in future photonics technology. This was done by studying the linear optical properties and nonlinear optical Phase Conjugation properties of two azo dye-doped polymer films by considering organic dyes disperse orange (DO-25) and disperse yellow (DY-7) doped in a polymer matrix Polymethyl methacrylate methacrylic acid (PMMA-MA). The nonlinear optical phase conjugation properties are studied using Degenerate Four Wave Mixing setup using 532 nm wavelength CW laser beam. The effect of dye concentration, intensity of backward, forward pump, and inter beam angle between probe and forward pump beam on phase conjugation reflectivity are also studied and compared.

- by Sreeramana Aithal
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- All Optical Switch, Optical Phase Conjugation

Fabrication of an all-optical switchable holographic liquid crystal (LC) Fresnel lens based on azo-dye- doped polymer-dispersed LCs is reported using a Michelson interferometer. It is found that, upon circu- larly polarized photoirradiation, the diffraction efficiency of the fabricated Fresnel lens was increased significantly in a reversible manner. We believe this is due to the anisotropy induced by reorientation of the LC molecules coupled with azo-dye molecule orientation due to trans–cis–trans photoisomeriza- tion, which modulates the refractive index of the LC-rich regions. We also studied the effect of azo dye on the polarization dependency of the fabricated lens.

- by Hossein Jashnsaz
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- Laser, Liquid Crystals, Optical switching, Optics and liquid crystals

In this paper, a novel fiber-based magnetooptic (MO) latching circuit using a bismuth-substituted yttrium iron garnet (Bi:YIG) is presented. Experimentation shows that nearly 90° of rotation of the state of polarization of incident light occurs between material latching states upon application of an external magnetic field greater than 500 G. This amount of rotation is enough to cause sufficient routing at the output of an optical interferometer of Sagnac configuration, which is presented in this paper. Due to the high coercivity of the Bi:YIG, the material remains in its magnetized state for very long periods of time and is thus latched. Reversing
the applied magnetic field changes the state of the material, unlatching it. This capability has great importance for nonreciprocal all-optical devices requiring low power operation. In addition, having such control of the state of the nonreciprocal elements can allow for a wider diversification of small-scale and large-scale optical network design. A discussion of the experimental setup, the resulting measurement data, and its implication for future low power applications is presented.

- by Prabesh Dulal
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- Fiber Optics, Garnets, Magneto-optics, All Optical Switch
- by Ezeddin Mohajerani
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- Mechanical Engineering, Materials Science, Laser, Liquid Crystals
- by MANI MINA
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- Engineering, Fiber Optics, Garnets, Physical sciences

Increasing demand for power reduction in computer systems has led to new trends in computations and computer design including reversible computing. Its main aim is to eliminate power dissipation in logical elements but can have some other advantages such as data security and error prevention. Because of interesting properties of reversible computing, implementing computing devices with reversible manner is the only way to make the reversible computing a reality. In recent years, reversible logic has turned out to be a promising computing paradigm having application in CMOS, nanotechnol- ogy, quantum computing and optical computing. In this paper, we propose and realize a novel implementation of Toffoli gate in all-optical domain. We have explained its principle of operations and described an actual experimental implementation. The all-optical reversible gate presented in this paper will be useful in different applications such as arithmetic and logical operations in the domain of reversible logic-based computing.

- by Hossein Jashnsaz
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- Quantum Computing, Logic, Polymer science, Interferometry