MZI Switches Research Articles

Low thermal crosstalk silicon MZI optical switch with high speed and low power consumption

Abstract We developed a compact thermo-optic Mach–Zehnder interferometer switch with a direct heating heater using multimode interference and achieved a sufficiently low thermal crosstalk performance. Large-scale switch systems, such as optical neural networks, require thermo-optical switches with low power consumption, fast switching speed, compact size, and low thermal crosstalk. This switch is equipped with a heater that directly heats the Si core waveguide, which is a structure that connects non-doped Si wires between phase shifters and a heatsink. As a result, a significant miniaturization with a phase shifter length of approximately 7 μm, low π-phase shift power consumption of less than 20 mW, and fast switching in sub-microseconds were achieved. The improved phase shifter showed a very small figure of merit of 8.89 mW∙μs. Simultaneously, transmission spectrum measurements of nearby ring resonators show that the thermal crosstalk is significantly reduced even at a distance of only 30 μm. This device can contribute to the overall circuit performance and footprint reduction in large-scale optical integrated circuits and optical neural network configurations.

Analysis of interferometric configuration for optical devices

Abstract With the exponential growth in information related applications and the continuous increase in voice over IP (VoIP) applications, the carriers are expanding their networks to provide improved services to their end users. In such cases, the synchronous optical network/synchronous digital hierarchy model is not suitable. In this work, we are going to investigate the electro optic switch with the help of a VB script to simulate the device for various parameters. Further, we will then scan the central electrode voltages and take account of the overlap integral taking place at the output port with the help of waveguide mode. The best switching for switches at different voltages so as to have negligible coupling loss for different input signals is investigated. We aim to evaluate the MZI switches with the Li-Tn channel profile wave guiding structure and confirm their performance as compared to the existing MZI switches.

Graphene-embedded first-order mode polymer Mach-Zender interferometer thermo-optic switch with low power consumption.

Two-dimensional-material integrated thermal optical switches have low power consumption; however, the devices are suffering from high propagation loss due to the two-dimensional material absorption. In this Letter, we present a graphene-embedded polymer Mach-Zender interferometer (MZI) thermo-optic switch, based on the E01x mode and designed to minimize both the loss and power consumption. Based on the symmetry of a three-dimensional structure and the E01x mode, the central embedded graphene electrode structure was simulated with an absorption loss of 0.06dB/cm. Finite element method (FEM) simulations were run to find that the power consumption is 1.57mW. Compared with the top heating electrode, the power consumption of the proposed graphene-embedded device is reduced by 74%. Further, the response speed of the graphene-embedded thermo-optic MZI switch is simulated to be 1.2μs (rise) and 70.6μs (down). This device may be applicable in the two-dimensional integrated low-power-consumption-mode division multiplexer field.

Performance analysis of metal-microheater integrated silicon waveguide phase-shifters

A detailed theoretical and experimental study of metal-microheater integrated silicon waveguide phase-shifters has been carried out. It has been shown that the effective thermal conductance gw and the effective heat capacitance hw evaluated per unit length of the waveguide are two useful parameters contributing to the overall performance of a thermo-optic phase-shifter. Calculated values of temperature sensitivity, SH = 1/gw and thermal response time, τth = hw/gw of the phase-shifter are found to be consistent with the experimental results. Thus, a new parameter ℱH = SH/τth = 1/hw has been introduced to capture the overall figure of merit of a thermo-optic phase-shifter. A folded waveguide phase-shifter design integrated in one of the arms of a balanced MZI switch is shown to be superior to that of a straight waveguide phase-shifter of the same waveguide cross-sectional geometry. The MZI switches were designed to operate in TE-polarization over a broad wavelength range (λ ∼ 1550 nm).

All Optical High Speed Multiplexer Circuit for Verification of Proposed Gates

Abstract An all optical communication is fast and reliable for next generation information carrying systems. For successful operation of fast data over flexible transmission line is only possible by all optical multiplexer and can serve for network. A 60 Gbps all optical multiplexer using cheap components has been realized and also tested on different speeds of input data streams. For integral and flexible multiplexer, optical semiconductor-based MZI switch taken into consideration. MZI-SOA is used to generate two logical gates outputs such as (AND)(XOR) gate. Multiplexer working is based on SOA nonlinearity properties and optical coupler. XOR logic gate contingent on cross-phase modulation in amplifier and logic AND for four-wave mixing is obtained from cross port and bar port respectively. Simulation is performed and multiplexer is tested for different launched power in tree architecture. System performance indicates that it can work for high speed (60 Gbps) and different data entities.

Preparation of Waveguide Polymer and its Simulation Study of Thermo-Optic Switch at the Infrared Communication Wavelength 1.55 μm

Abstract In the current work, a novel benzothiazole waveguide polymer consisting of azo chromophore molecule 2 -[4'-(N, N-hydroxyethyl)-amino-phenyl azo]-6-nitrobenzothiazole (HEPNBT) was prepared for the simulation of thermo-optic switch at the infrared communication wavelength 1.55 μm. The thermal property of ABHEPU was measured using the differential scanning calorimeter (DSC) and thermal gravimetric analysis (TGA). The glass transition temperature (T g ) and decomposition temperature (T d ) at 5% mass loss are 110 ℃ and 266 ℃, respectively. The refractive indices of ABHEPU waveguide polymer were determined at different wavelength (532 nm, 650 nm or 850 nm) and temperature using attenuated total reflection (ATR) technique. The transmission loss, dispersion curves and Sellmyer coefficients of ABHEPU polymer were investigated from CCD digital imaging devices and Sellmyer equation, respectively. Polymeric 1 × 2 and Mach–Zehnder interferometer (MZI) thermo-optic switches based on the ABHEPU as waveguide material at the infrared communication wavelength 1.55 μm were designed and simulated. Simulation results with FD-BPM method showed that the power consumption of 1 × 2 thermo-optic switch is only 0.58 mW; and the response times of 1 × 2 and MZI switches are 12 ms and 3.0 ms for the designed device. The switching time of the prepared ABHEPU polymer is much shorter than that of silica substrate.

Simulation of an All Optical Full Adder using Optical Switch

The optical communication system has many advantages at long distance communication. Semiconductor optical amplifier based Mach Zehnder Interferometer plays an important role in fast optical communication. In this work the proposed SOA based MZI switch is used for all optical logic and arithmetic operations. In this architecture the continuous wave laser source and control signal pass through the Mach Zehnder Interferometer. Control signal at this wave length is split at the coupler and more power passes through one arm. The input data signal is fed to the coupler, which splits the signal equally. The resultant signals then propagates simultaneously through the two arms of the interferometer. This architecture can be used to perform all optical processing of signals like half adder, full adder, de multiplexer etc. MZI switch is a very powerful technique to realize ultrafast switching. The physical mechanism behind the working of MZI switch is cross-phase modulation (XPM). Here the gain saturation induced by beam reduces carrier density inside one SOA, which in turn increases the refractive index only in the arm through which the light passes. As a result, an additional phase shift can be introduced on the CW beam because of the XPM, and the CW wave is directed towards the bar port during each one bit. Now it is clear that in the absence of control signal, the incoming signal (CW signal) exits through the cross port (lower channel) of MZI. In this case no light is present in the bar port. But in the presence of the control signal, the incoming signal exits through the bar port of the MZI.

Optical time division multiplexing at 160 Gbps using MZI switching

Many lower-speed data streams can be multiplexed into one high-speed stream by means of optical time division multiplexing (OTDM), such that each input channel transmits its data in an assigned time slot. The simulation is performed by a fast multiplexer switch (mux). The routing of different data streams at the end of the TDM link is performed by a demultiplexer switch (demux) and this demultiplexer is employed using MZI switch as it consists a semiconductor optical amplifier (SOA) and an optical coupler. In this paper four channel OTDM is simulated at 40 Gbit/s and further the impact of the signal power, pulse width and control signal power on BER is investigated.

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

The need for increasingly high-speed digital optical systems and optical processors demands ultra-fast all-optical logic and arithmetic units. In this paper, we combine the attractive and powerful parallelism property of the modified signed-digit (MSD) number representation with the ultra-fast all-optical switching property of the semiconductor optical amplifier and Mach–Zehnder interferometer (SOA–MZI) to design and implement all-optical MSD adder/subtracter circuits. Non-minimized and minimized techniques are presented to design and realize efficient circuits to perform arithmetic operations. Several all-optical circuits’ designs are proposed with the objective to minimize the number of the SOA–MZI switches, the time delay units in the adders, and other optical elements. To use the switching property of the SOA–MZI structure, two bits per digit binary encoding for each of the trinary MSD digits are used. The proposed optical circuits will be very helpful in developing hardware modules for optical digital computing processors.

Tap-and-2-Split Switch Design Based on Integrated Optics for Light-Tree Routing in WDM Networks

This paper presents a novel cost-effective multicast-capable optical cross connect (MC-OXC) node architecture that features both tap-and-continue and tap-and-binary-split functionality. This architecture provides an interesting balance between simplicity, power efficiency and overall wavelength consumption with respect to models based on TaC (Tap and Continue) or SaD (Split-and-Delivery). The main component of this node is a novel Tap-and-2-Split Switch (Ta2S). In this paper, we propose and analyse an implementation of this switch based on integrated optics (namely, MMI taps and MZI switches), and we characterize and compare it with other alternatives implemented with the same technology. The study shows that, thanks to the presented Ta2S design, the 2-Split Tap Continue (2STC) node scales better in terms of number of components than the other alternatives. Moreover, it is more power efficient than the SaD design and requires less wavelengths than TaC thanks to the binary split capability. On the other hand, simulation results reveal that the 2-split condition does not add a significant additional wavelength consumption in usual network topologies with respect to SaD.

Optical signal processing using integrated multi-element SOA–MZI switch arrays for packet switching

The use of discrete but interconnected SOA - MZI switches for performing logical and highly functional processing tasks, demonstrating the multi-functional potential of the photonic switching elements is discussed. An all-optical 3R burst-mode receiver consisting of four SOA - MZI switches and operating error-free with 40 Gb/s optical bursts, proving that interconnection of multiple switching units can lead to the realisation of key network node functionalities offering increased intelligence at the physical layer is presented. In order to allow for easier interconnectiv- ity between the SOA - MZI switches and to provide compactness and cost effectiveness to the developed subsystems, the integration of multiple switches into the same platform is proposed. To this end, the implementation of the first integrated quadruple SOA - MZI switch array is reported, increasing the integration density level and reducing packaging and pigtailing costs. Finally, possible applications of integrated multiple switch arrays are discussed, indicating their suitability for producing compact circuits performing common processing tasks in a multi- wavelength environment, as well as their potential to lead to the development of an all-optical high- speed packet switched node by implementing critical packet switching functionalities in a compact and efficient way.

Compact all-optical packet clock and data recovery circuit using generic integrated MZI switches

We present and evaluate a compact, all-optical Clock and Data Recovery (CDR) circuit based on integrated Mach Zehnder interferometric switches. Successful operation for short packet-mode traffic of variable length and phase alignment is demonstrated. The acquired clock signal rises within 2 bits and decays within 15 bits, irrespective of packet length and phase. Error-free operation is demonstrated at 10 Gb/s.