Implementation of full-adder and full-subtractor based on electro-optic effect in Mach–Zehnder interferometers

We present the design of a 2×2 photonic switch operating at 1.55-μm wavelength using electro-optic (EO) polymer waveguides. A Mach-Zehnder interferometer (MZI) is used to implement the proposed switch in which two identical 2×2 multimode interference (MMI) couplers are connected by two identical parallel single mode waveguides (two MZI arms). These two single-mode waveguides with electrodes allow modulating the phase difference between the two MZI arms based on the EO effect. In the proposed switch, the EO polymer, IPC-E/polysulfone, is used for the core layer of optical waveguides. UV15 and NOA61 are employed for the lower and upper cladding layers, respectively. The singlemode waveguide structure and 2×2 MMI coupler have been designed and analyzed for the EO switch. Device performance has been simulated using the beam propagation method. It is found that the switch performance is most sensitive to the MMI width and less sensitive to the MMI length. Optimized structure has been obtained for the 2×2 polymeric EO switch, which has a crosstalk level better than -25 dB and insertion loss lower than -1.8 dB. This performance makes the switch a potential candidate for practical use in photonic systems.

In this paper, the SWAP gate is realized using the electro-optic (EO) phenomenon in the Mach-Zehnder Interferometer (MZI). In the structuring of the SWAP gate, two MZI is being used, and output is obtained from the bar port of both MZI. The SWAP gate output is obtained from MATLAB by using the mathematical description of MZI. The proposed layout of the SWAP gate is designed using titanium diffused lithium niobate (Ti:LiNb03) waveguide and simulated using the beam propagation method (BPM) at 1.33 μm wavelength.

The Mach-Zehnder Interferometer is one of the fundamental components in a photonic circuit. It has a variety of functions, such as wavelength filtering, optical switching, and optical sensing. Gallium Nitride (GaN) semiconductor-based devices have been a source of interest for photonic device researchers, owing to their ability to operate at high temperatures and high power levels. In this work, we have investigated the effect of wavelength variation on the relative power in the Mach- Zehnder Interferometer structure, based on two directional couplers using GaN on Sapphire as a preliminary study to design the wavelength selections. The structure was optimised using OptiBPM with the beam propagation method. We optimised the structure by varying length of the waveguide and the gap between the top and bottom waveguide. Based on the results of the numerical experiment, we found the best length and gap value of the Mach-Zehnder Interferometer to be 14500 μm and 36μm. It also shown that optical field propagation is uniform and the relative power reaches 0.93 at a 1.55μm wavelength. The simulation was conducted using a wavelength range from 1.50 up to 1.60 μm with increments of 0.01 μm to obtain the performance of structure at the C-band range. By varying wavelength from 1.50 up to 1.60 μm, the result indicate that the optical field propagation is uniform and the relative power almost stable at 0.9.

In mode-locked fiber lasers and optical sensors, in-line filters are essential components. Fiber-core Mach–Zehnder interferometer (MZI) technology has garnered a lot of research interest for the several manufacturing techniques for in-line MZI filters. Although multi-line inscription is frequently needed in existing methods to attain enough waveguide width, this approach adds complexity to production and may result in compromised waveguide quality. In this work, we present an improved single-line direct-writing method that attains similar MZI filtering results to multi-line scan. Additionally, the MZI filter created with the modified single-line direct-writing technique has a smaller insertion loss and requires less direct-writing energy than the previous single-line direct-writing technique. A 516 μm long MZI-based in-line filter was successfully constructed. The results of the characterization showed a central loss dip at 1089.82 nm, a free-spectral range (FSR) of 141.36 nm, an extinction ratio of 19.69 dB, and an insertion loss of 1.122 dB. This method decreased the insertion loss by a factor of 2.7 for an identical extinction ratio and improved the direct-writing efficiency by a factor of 9 for an equivalent FSR with multi-line scan. There was consistency between the experimental and simulation results. We also took measurements of the MZI’s temperature sensitivity. This work shows notable improvements in waveguide quality and ease of manufacture. This accomplishment lays the groundwork for further advancements in integrated mode-locked fiber laser technology.

Electrooptic intensity modulators are important components for fiber-optic communication and high-speed signal processing. The on/off extinction ratio, drive voltage, and insertion loss are important parameters that determine the performance of the modulators. Recently, an electrooptic cutoff modulator using a Ti-indiffused LiNbO3 channel waveguide with asymmetric strip electrodes was demonstrated with an extinction ratio of >56 dB.1 When a voltage is applied, the asymmetric configuration prevents most of the radiated light from being transferred back to the guide, thus greatly improving the on/off extinction ratio. The drive voltage of such a device, however, is quite high since the gap between the electrodes is considerably wider than the channel width. We propose an electrooptic cutoff modulator using low-loss-diffused channel waveguide bends. The proposed device shows an asymmetric effective index profile by which electrooptic modulation can be enhanced. Analysis based on the beam propagation method has shown that this device has a high extinction ratio with a low drive voltage. Design considerations are presented.

Fabrication and error analysis of a InGaAsP/InP polarization beam splitter based on an asymmetric Mach-Zehnder interferometer

An all-fiber Mach-Zehnder interferometer (MZI) interleaver using one planar 3×3 fiber coupler, one 2×2 fiber coupler and one 8-shaped fiber ring resonator is developed by the new configuration. Based on its structure, the output spectrum expression is established and described by using the principle of fiber transmission and the matrix transfer function. The results of numerical simulation indicate that when the length difference of interference arms and the coupling coefficients of the couplers are some certain values, it obtains a uniform flat-top passband and similar to rectangular output spectrum. Compared with the traditional MZI interleaver, the isolation in stopband and the rolloff in transition band are strengthen, the 25dB stopband bandwidth and 0.5dB passband bandwidth are simultaneously remarkably improved. Compared with the asymmetrical ring resonator MZI interleaver, the influence of transmission loss on extinction ratio can be effectively reduced. The device has a certain ability to resist the deviation, which reduces the difficulties in fabricating it. The experiment results agree with the theoretical analysis well. The interleaver designed by the proposed approach has favorable performance, which has the potential application value in optical fiber communication system.

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <?Pub Dtl=""?>Generation of optical millimeter-wave (mm-wave) signal using a Mach–Zehnder modulator (MZM) based on double-sideband (DSB), single-sideband (SSB), and double-sideband with carrier suppression (DSBCS) modulation schemes have been demonstrated for various applications, such as broadband wireless signals or optical up-conversion for wavelength-division-multiplexing (WDM) radio-over-fiber (RoF) network, wideband surveillance, spread spectrum, and software-defined radio. Among these schemes, DSBCS modulation offers the best receiver sensitivity, lowest spectral occupancy, the least stringent requirement of electrical bandwidth, and the smallest receiving power penalty after long transmission distance. Nonetheless, the inherent nonlinear E/O (electrical/optical) conversion response of a MZM is such that the signal quality of the optical mm-wave suffers. Fabrication tolerances make a balanced 50/50 splitting ratio of the MZM's y-splitter particularly difficult to achieve. As a result, imbalanced MZMs have a finite extinction ratio (ER) and degrade the optical carrier suppression ratio (OCSR) using DSBCS modulation. In this paper, the effect of the MZM nonlinearity and imbalanced y-splitter on optical mm-wave generation by DSBCS modulation is theoretically and experimentally investigated. A novel approach with better performance and greater cost-effectiveness than dual-electrode MZM (DD-MZM) is presented to realize a DSBCS modulation scheme based on a single-electrode MZM (SD-MZM). </para>

We propose a new structure for multilevel pulse amplitude modulation (PAM-4) signal generation for on-chip optical interconnects and data center networks. Our proposed architecture use only one 3 × 3 multimode interference (MMI) Based ring resonator with two segmented phase shifters. Two segmented phase shifters applied the plasma dispersion effect in silicon waveguide are used in the feedback ring resonator waveguide. The structure provides a very steep slope compared with the conventional structure based on Mach Zehnder Interferometer (MZM). As a result, an extreme reduction of power consumption is achieved. Based on this structure, an extreme high bandwidth and compact footprint are also achieved. The device is designed and analyzed using the Beam Propagation Method (BPM) integrated with the Finite Difference-Time Difference (FDTD) simulations.KeywordsMultimode interference (MMI)Microring resonatorIntegrated opticsPAM-4High performance computing systemsData center networksOptical interconnects

In the presented structure, the performance of the all-optical XOR logic gate (AO-XOR-LG) is investigated. The XOR-LG is designed and simulated using a photonic crystal semiconductor optical amplifier (PC-SOA) based on Mach–Zehnder interferometer (MZI) and cross-phase modulation (XPM) nonlinear mechanism. The input optical pulse train used in this simulation is the type of RZ (Return-to-Zero). The finite difference method (FDM) has been used to solve the rate and propagation equations. The effect of input signal energy, bias current, and group refractive index on the output signal and gain of the XOR-LG is studied. The optimal mode is obtained for the XOR-LG with a bit rate of 80 Gbps. Furthermore, for the first time, the effects of quality factor (QF), conversion efficiency (CE), extinction ratio (ER), pattern effect (PE), and gain recovery are simultaneously analyzed in the simulation to increase PC-SOA performance. According to the results, PC-SOA has a more reasonable logic performance than conventional SOA, and due to its much shorter length than SOA, it can be a much better choice for integrated optical circuits.

In this letter, we experimentally demonstrate improved static and dynamic characteristics of the all-optical 2R regenerator based on a Mach-Zehnder interferometer with gain-clamped semiconductor optical amplifiers. A true digital-like optical decision characteristic with an adjustable decision threshold has been found. A tremendous noise suppression at the logic 0 and a large improvement in the extinction ratio have been obtained even for a very deteriorated input signal with small extinction ratio at a bit rate of 2.488 Gb/s. An 8-dB improvement in extinction ratio can be achieved for an input extinction ratio of 5- and 7-dB improvement for an input extinction ratio of 2 dB. Furthermore, a good regeneration is achieved over a broad wavelength range of 20 nm.

Data communication around the whole globe has seen an enormous increase in the exchange of data across the networks. This has urged the need of optical communication systems that can provide the desired bandwidth. This paper is a step to the path of building such optical processing elements. The paper presents optical designs of a 3-bit incrementer and a 3- bit decrementer logic function. The two optical circuits increment or decrement each 3-bit input binary number by unity. The optical designs have been implemented using the LiNbO₃ based Mach-Zehnder Interferometer (LNMZI) electrooptical switches. The incrementer circuit has employed just five LNMZIs and the decrementer circuit has only six LNMZIs. The optical circuits have been designed and tested using beam propagation method (BPM). A critical analysis of the two designs has been performed by calculation of the important performance metric parameters like extinction ratio (ER), contrast ratio (CR), insertion loss (IL). The incrementer/decrementer shows best values of ER, CR and IL as 31.43 dB, 35.71 dB and 0.95 dB respectively. The calculated parameters have been found within the acceptable limits which support the feasibility of the design.

In this article, an optical majority/minority circuit has been designed using four electro‐optic Mach‐Zehnder interferometers. The binary decision diagram (BDD) is used to optimize the Boolean logical expression. In this design we get two outputs, one performs majority logic and the other performs minority logic simultaneously. Numerical simulation has been done with the obtained data from the beam propagation method. Pseudo‐eye diagram is also plotted to find amplitude modulation (AM) and extinction ratio (ER). AM and ER are found nearly 0.4 and 13 dB, respectively. A new parameter, the optical circuit complexity factor (OCC) factor has been calculated and from the result, it has been shown that the proposed design is more optimized than other majority/minority gate designs so far.

A fully reconfigurable Fano resonator on a silicon photonic chip is reported. The Fano resonator is realized with the use of an add-drop micro-disk resonator (MDR) and a Mach-Zehnder interferometer (MZI). The waveguides at the through and drop ports of the MDR connect to two spiral waveguide arms of the MZI directly. Two independent metallic micro-heaters are incorporated on top of the MDR and the lower arm of the MZI. Thanks to the resonant mode interference between the MDR and the MZI, the Fano resonance occurs. By thermal tuning the resonance coupling between the MDR and the MZI, the generated Fano resonance is fully tunable. In addition to the independent tunable slope rate (SR) and the resonance wavelength, the Fano resonance wavelength can shift while its line shape remains by simultaneously controlling the two micro-heaters. A chip is designed, fabricated and evaluated. The measurement results show that the static Fano resonance has a line shape with an extinction ratio (ER) of 17.1 dB and SR of &#x2212;13.6 dB&#x002F;nm. By simultaneously controlling the two micro-heaters, full reconfigurability of the Fano resonance is demonstrated. Thanks to its straightforward configuration, the proposed Fano resonator holds the key advantage in terms of ultra-compactness and fully reconfigurability, which offers a great potential for applications such as on-chip optical switching, modulation and microwave photonics applications.

In future wavelength-division multiplexed (WDM) reconfigurable networks, the ability to shift a signal from one wavelength to another may be an essential function due to a limited number of available wavelengths. The Mach-Zehnder interferometer (MZI) has sparked the interest of the WDM community because ofits ability to wavelength convert signals at high speed, in both inverting and noninverting configurations with a high output extinction ratio, and with low chirp. In this paper, we assess the stability of the extinction ratio of the MZI with variations in the SOA bias currents, as well as with the wavelength and the power of the pump and probe. We characterize the operating point stability of the MZI and find ranges for the bias currents and for the input parameters, in order to minimize the sensitivity of the extinction ratio (ER).