All-optical Decoder Research Articles

Compact all-optical decoder design for optical integrated circuits.

This paper constructs and discusses a 1×2 decoder based on two-dimensional photonic crystals. The designed decoder is a priority decoder with one main input and one enabled input. This logic circuit's structure is very simple and compact, and it employs a photonic crystal structure with dimensions of 11×11 rods built of GaAs. The calculation results reveal that the output power values for logical mode 1 are extremely close to the power of the light source, whereas the power is very low and close to zero in logical mode 0. As a result, the difference between logical values 0 and 1 in the output will be adequate, and the circuit's accuracy will be good. The finite difference-time domain (FDTD) approach is used for time computations and light propagation in waveguides.

Design of 1-to-2-line all-optical decoder based on MMI phase shifter

Design of 1-to-2-line all-optical decoder based on MMI phase shifter

Ultra-fast all-optical decoder based on nonlinear photonic crystal ring resonators.

In this paper, a 2-to-4 all-optical decoder based on photonic crystal ring resonators is introduced. The photonic crystal structure has a 2D square chalcogenide rod lattice whose maximum response time is 2ps. Three ring resonators including nonlinear rods with 9×10-17 m2/W for a Kerr coefficient carry out a switching operation at 1550nm wavelength. The switching speed of the device is 500GHz, which is more than that in previously presented works. Also, the small size of the structure is sufficient for optical integrated circuits.

A novel proposal for all-optical decoder based on photonic crystals

In this paper, a new structure for all-optical 2-to-4 decoder is proposed which consists of six nonlinear photonic crystal ring resonators. The lattice constant of the main structure is a = 600 nm, and the refractive index and radii of rods are 3.1 and 0.2a, respectively. Simulation results have proved correct operation states of the decoder and numerical analysis is done in order to additional evaluation. The maximum and minimum power levels for logic 0 and 1 are $$0.1P_{\mathrm{in}}$$ and $$0.37P_{\mathrm{in}}$$ where $$P_{\mathrm{in}}$$ is input power. The maximum cross talk and insertion loss are calculated about −38 and −20 dB, respectively. Since the operation speed of the decoder is more than 160 GHz, it will be appropriate candidate for being employed in ultrahigh-speed optical communication systems.

Design and analysis of integrated all-optical $$2\times 4$$ 2 × 4 decoder based on 2D photonic crystals

In the development of the technology of all-optical integrated circuits, the logic gates play considerable role in the progress of optical components. As one of the main building-blocks of an optical system, a high-performance 2*4 all-optical decoder is proposed and studied based on nonlinear effects in a photonic crystal ring resonator. The proposed structure consists of 1*2 decoders which are combined to operate as a unique 2*4 decoder and this will let us to extend the design to decoders with increased inputs. An optical bias is used to interact with input signals, and each output port is enabled for a given code in the input code. Numerical simulation methods such as plane wave expansion and finite difference time domain are performed to study the operation of proposed structure. Results of simulations show that for an on-state output, the highest achievable power is about 87% and the lowest value is 40%. For the case of 40%, the on/off ratio of outputs is at least 2.22 which ensures the acceptable resolution needed for detection of on-state. Maximum cross-talk about −10 dB and insertion loss about −8.8 dB is obtained for proposed decoder.

All-Optical Decoder for Rapid and Noncontact Readout of Thermal Barcodes

An all-optical decoder was developed for remote rapid readout of the thermal barcode made of solid-to-liquid phase-change materials (PCMs). An infrared source was used to heat up barcode; a thermal imager (IR camera) was used to collect thermal images continuously while the barcode was heating up or cooling down. Thermal barcodes consisting of four types of PCMs were decoded by identifying abrupt changes in temperature profiles during heating (cooling) process. Instead of identifying melting temperatures via direct contact in traditional differential scanning calorimetry, the infrared heating and imaging techniques provide a noncontact and highly sensitive way to characterize material properties and decode thermal barcode at high spatial resolution.

Design of 2-to-4 All-Optical Decoder with the Help of Terahertz Optical Asymmetric Demultiplexer

An all-optical 2-to-4 decoder unit with the assist of terahertz optical asymmetric demultiplexer (TOAD) is presented. The all-optical 2-to-4 decoder with a set of all-optical switches is designed which can be used to achieve a high-speed central processor unit using optical hardware. The unique output lines can be used for all-optical header processing. We attempt to develop an integrated all-optical circuit which can perform decoding of signal. This scheme is very simple and flexible for performing different logic operation and to design advanced complex logic. Simulated results are confirming the described methods.

Optical-Logic-Gate Aided Packet-Switching in Transparent Optical Networks

The objective of this research is to propose two new optical procedures for packet routing and forwarding in the framework of transparent optical networks. The single-wavelength label-recognition and packet-forwarding unit, which represents the central physical constituent of the switching node, is fully described in both cases. The first architecture is a hybrid opto-electronic structure relying on an optical serial-to- parallel converter designed to slow down the label processing. The remaining switching operations are done electronically. The routing system remains transparent for the packet payloads. The second architecture is an all-optical architecture and is based on the implementation of all-optical decoding of the parallelized label. The packet-forwarding operations are done optically. The major subsystems required in both of the proposed architectures are described on the basis of nonlinear effects in semiconductor optical amplifiers. The experimental results are compatible with the integration of the whole architecture. Those subsystems are a 4-bit time-to-wavelength converter, a pulse extraction circuit, a an optical wavelength generator, a 3times8 all-optical decoder and a packet envelope detector.

All-Optical Packet-Switching Decoder Design and Demonstration at 10 Gb/s

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A 3 <formula formulatype="inline"><tex>$\times$</tex></formula> 8 all-optical decoder based on cross- polarization modulation in semiconductor optical amplifiers is demonstrated for the first time to our knowledge. The design requires a single active optical device per output. Experimental results are shown for return-to-zero modulated 10-Gb/s signals. Applications include label processing in optical packet switched optical networks. </para>

All-optical decoding method for ASCII-coded data using nonlinear-material-based switching

We propose an all-optical technique for decoding of ASCII-coded data. This method accommodates a decoding system using an all-optical AND logic gate. Optical switching with a nonlinear material is exploited here for the decoding.