The efficient application of the Mach–Zehnder interferometer (MZI) structure for the construction of the well-known logic gates is described. It deals with the effect of the varying voltages of each electrode on the performance of MZI. It has been found that power transmission gets switched with the variation of voltage in the electrodes. The results are of prime importance for optical gate implementation as well as being useful in the signal router. There is a commercial demand of optical gates and signal routers in dense wavelength division multiplexing. The result is also verified by proper analysis using OptiBPM and matlab softwares.

Implementation of optical switches using Mach–Zehnder interferometer

In recent years reversible logic has emerged as a promising computing model for applications in dissipation less optical computing, low power CMOS, quantum computing, etc. In reversible circuits there exist a one-to-one mapping between the inputs and the outputs resulting in no loss of information. Researchers have implemented reversible logic gates in optical computing domain as it can provide high speed and low energy requirement along with easy fabrication at the chip level [1]. The all optical implementation of reversible gates are based on semiconductor optical amplifier (SOA) based Mach-Zehnder interferometer (MZI) due to its significant advantages such as high speed, low power, fast switching time and ease in fabrication. In this work we present the all optical implementation of an n bit reversible ripple carry adder for the first time in literature. The all optical reversible adder design is based on two new optical reversible gates referred as optical reversible gate I (ORG-I) and optical reversible gate II (ORG-II) and the existing all optical Feynman gate. The two new reversible gates ORG-I and ORGI-I are proposed as they can implement a reversible adder with reduced optical cost which is the measure of number of MZIs switches and the propagation delay, and with zero overhead in terms of number of ancilla inputs and the garbage outputs. The proposed all optical reversible adder design based on the ORG-I and ORG-II reversible gates are compared and shown to be better than the other existing designs of reversible adder proposed in non-optical domain in terms of number of MZIs, delay, number of ancilla inputs and the garbage outputs. The proposed all optical reversible ripple carry adder will be a key component of an all optical reversible ALU that can be applied in a wide variety of optical signal processing applications.

Mach-zehnder interferometer based design of all optical reversible binary adder

Reversible logic has promising applications in dissipation less optical computing, low power computing, quantum computing etc. Reversible circuits do not lose information, and there is a one to one mapping between the input and the output vectors. In recent years researchers have implemented reversible logic gates in optical domain as it provides high speed and low energy computations. The reversible gates can be easily fabricated at the chip level using optical computing. The all optical implementation of reversible logic gates are based on semiconductor optical amplifier (SOA) based Mach-Zehnder interferometer (MZI). The Mach-Zehnder interferometer has advantages such as high speed, low power, easy fabrication and fast switching time. In the existing literature, the NAND logic based implementation is the only implementation available for reversible gates and functions. There is a lack of research in the direction of NOR logic based implementation of reversible gates and functions. In this work, we propose the NOR logic based all optical reversible gates referred as all optical TNOR gate and all optical PNOR gate. The proposed all optical reversible NOR logic gates can implement the reversible boolean logic functions with reduced optical cost and propagation delay compared to their implementation using existing all optical reversible NAND gates. The advantages in terms of optical cost and delay is illustrated by implementing 13 standard boolean functions that can represent all 256 possible combinations of three variable boolean function.

Mach-Zehnder Interferometer Based All Optical Reversible NOR Gates

In this paper, we present improved all-optical circuits that implement ultra-fast adders based on the carry-free property of the modified signed-digit (MSD) number representation. The all-optical realizations are based on semiconductor optical amplifier (SOA) and Mach–Zehnder interferometer (MZI) switches, which represent one of the most promising solutions due to their compact size, thermal stability and low power operation. Several all-optical circuit designs are proposed with the objective to minimize the number of the SOA–MZI switches, the time delay in the adders and some other optical elements. The proposed circuits are more efficient comparing to previously published ones in terms of the number of optical components (less by 50%) as well as the operational speed (faster by 50%).

Improved all-optical modified signed-digit adders using semiconductor optical amplifier and Mach–Zehnder interferometer

With the advancements in silicon photonics, optical devices have found applications e.g. for ultra-high speed and low-power interconnects as well as functional computations to be realized on-chip. Caused by the increasing complexity of the underlying functionality, also the need for computer-aided design methods for this technology rises. Motivated by that, initial work on the development of synthesis methods for optical circuits has been performed. But all approaches proposed thus far suffer e.g. from unsatisfactory synthesis results or restricted scalability. In particular, splittings in the resulting circuits which degrade the optical signals into hardly measurable fractions prevent an efficient and scalable synthesis for optical circuits. In this work, we present a synthesis approach based on Binary Decision Diagrams (BDDs) that overcomes these obstacles. The approach yields circuits that rely on a total of zero splitters - at the expense of a moderate increase in the number of optical gates. Experiments confirm that, by this, an efficient and scalable synthesis scheme for optical circuits eventually becomes available.

/pdf/reverse-bdd-based-synthesis-for-splitter-free-optical-4trkwamgdh.pdf

Reverse BDD-based synthesis for splitter-free optical circuits

Circuit designs of ultra-fast all-optical modified signed-digit adders using semiconductor optical amplifier and Mach-Zehnder interferometer

All-optical ultra-fast arithmetic circuits are presented using nonlinear optical material. The all-optical proposed circuits use semiconductor optical amplifier and Mach-Zehnder interferometer as switches due to their compact size, thermal stability and low power operation.

Ayman S. Al-Zayed

Papers

Circuit designs of ultra-fast all-optical modified signed-digit adders using semiconductor optical amplifier and Mach-Zehnder interferometer

All-Optical Ultra-Fast Arithmetic Units Using Nonlinear Optical Materials