Understanding the Performance Guarantee of Physical Topology Design for Optical Circuit Switched Data Centers

As a first step of designing O ptical-circuit-switched D ata C enters (ODC), physical topology design is critical as it determines the scalability and the performance limit of the entire ODC. However, prior works on ODC have not yet paid much attention to physical topology design, and the adopted physical topologies either scale poorly, or lack performance guarantee. We offer a mathematical foundation for the design and performance analysis of ODC physical topologies in this paper. We introduce a new performance metric β(G ) to evaluate the gap between a physical topology G and the ideal physical topology. We develop a coupling technique that bypasses a significant amount of computational complexity of calculating β(G). Using β(G ) and the coupling technique, we study four physical topologies that are representative of those in literature, analyze their scalabilities and prove their performance guarantees. Our analysis may provide new guidance for network operators to design better physical topologies for their ODCs.

Simultaneous All-optical 1's Complement Cum Division-by-two Schemes

Odd and even number detection is an important mathematical operation. Generally when any number divisible by 2 then it is called even number, otherwise it is odd number. Division by 2 can be easily obtained by putting a point before least significant bit (LSB) of any binary number. As an example a number (27)10 = (11011)2 when divided by 2 its result will be (1101.1)2 = (13.5)10. Hence when we find the fractional bit as logic-1 we can say that the number is odd, otherwise it is even. This operation can be obtained by using a demultiplexer. Here we have developed an optical circuit which can divide any binary integer number by 2, apart from that its 1’s complement can also be obtained from the circuit. Both of the result can be obtained simultaneously. Terahertz optical asymmetric demultiplexer (TOAD) based generally switch assumes a vital part to plan this n-bit circuit. Numerical simulations are done to urge the exhibition of the circuit.

Superluminal Communication with Polarized Entangled Photons

In this work, we show that Quantum Mechanics predicts that two people who share entangled polarized pairs of photons can communicate faster than light. We show this communication only occurs in one direction, from Bob to Alice. Bob can send information to Alice by measuring the polarization of his photons in different directions. Alice can find out in which direction Bob has measured his photons by measuring how much light passes through an optical circuit. We show this communication is instantaneous because it is based on the collapse of the wave function of the entangled pair, which collapse is instantaneous. We conclude that regardless of whether this method of communication works or not in practice, we have something new because if it works, we would be contradicting the Theories of Relativity, and if it does not, we would have Quantum Mechanics predicting something that does not happen in real life.

Study of Lapping and Polishing Performance on Lithium Niobate Single Crystals

Recently, the range of crystal materials used in industrial microelectronics has significantly increased. Lithium niobate single crystals are most often used in integrated optics, due to the high values of optical and electro-optical coefficients. An integral-optical circuit based on a lithium niobate single crystal is a key element in the production of local high-precision fiber-optic gyroscopic devices used in civil and military aviation and marine technologies. In the process of production of an integral-optical circuit, the most labor-intensive operations are mechanical processing, such as lapping and polishing. Technological problems that arise while performing these operations are due to the physical and mechanical properties of the material, as well as target surface finish. This work shows the possibility to achieve the required surface quality of lithium niobate single crystal plates by mechanization of lapping and polishing process in this article.

Optical Rerouting in Glass Fibre Composite

We demonstrate for the first time the reconfigurability of optical signals within advanced laminated composite. The approach employs an ultra-thin planar optical circuit, embedded within glass fibre reinforced polymer (GFRP) that switches an optical input though Ohmic heating. This advance highlights new opportunities for optical reconfigurability within advanced composites, enabling data transmission redundancy and a consideration of branching optical fibre architectures.

Simultaneous All-optical 1's Complement Cum Division-by-two Schemes

Odd and even number detection is an important mathematical operation. Generally when any number divisible by 2 then it is called even number, otherwise it is odd number. Division by 2 can be easily obtained by putting a point before least significant bit (LSB) of any binary number. As an example a number (27)10 = (11011)2 when divided by 2 its result will be (1101.1)2 = (13.5)10. Hence when we find the fractional bit as logic-1 we can say that the number is odd, otherwise it is even. This operation can be obtained by using a demultiplexer. Here we have developed an optical circuit which can divide any binary integer number by 2, apart from that its 1’s complement can also be obtained from the circuit. Both of the result can be obtained simultaneously. Terahertz optical asymmetric demultiplexer (TOAD) based generally switch assumes a vital part to plan this n-bit circuit. Numerical simulations are done to urge the exhibition of the circuit.

Principles of constructing gyroscopes based on photonic crystal (band-gap) fibers

The gyroscope is a device that makes it possible to measure the change in the orientation angles associated rotation of the body relative to an inertial coordinate system. Photonic crystal fiber gyroscopes are a kind of optical gyroscopes that offer many new features beyond that conventional fiber optic gyroscopes can offer. In any case, the properties of the optical fiber can play a large role in determining the characteristics of the gyroscope. The principle of operation of most optical gyroscopes is based on the Sagnac effect or the Sagnac interferometer, the essence of which is as follows. If two light waves propagate in a closed optical circuit in opposite directions, then in the case of an immovable circuit, the phase incursions of both waves that have passed the entire circuit in opposite directions will be the same. When the contour rotates around an axis normal to the contour plane, the phase incursions of the waves become unequal, and their difference in the general case will be proportional to the angular velocity of the contour rotation, the area covered by the contour, and the frequency of the electromagnetic wave (EMW). Since the area and frequency of the EMW remain unchanged during the operation of the gyroscope, the phase shift will be proportional only to the angular velocity. The use of photonic crystal fiber to increase the sensitivity is very promising; it significantly reduces the drift through thermal polarization, resistance, and the Kerr effect. This article suggests the use of photonic-crystal (hollow-core) fiber in optical gyroscope instead of conventional fibers.