Realization of SWAP Gate using Electro-Optic Phenomenon-based Mach-Zehnder Interferometer

Electro-optic Mach-Zehnder interferometer (MZI) switches are well known devices in optical systems for their high speed of operation. In next generation optical network, such switches have wide applications due to their high switching capability and great reliability. In this paper we have investigated the enhanced performance of an electro-optic switch made by titanium diffused lithium niobate (Ti:LiNbO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ) functioned as waveguide medium based on integrated Mach-Zehnder interferometer (MZI) at 1.55 μm wavelength. The performance of the switch is optimized for low switching voltage, low insertion loss, high extinction ratio. This is done by varying the strip thickness of titanium, interferometer arm length, arm gap, waveguide width, gap in the coupling region of the 3 dB couplers, and center position of second electrode deposited on integrated Mach-zehnder Interferometer arm with respect to the original axis of the switch. The designed switch gives lowest insertion loss of 0.00881dB and highest extinction ratio of 33.581 dB at 8.8 V.

Optical communication has proven its capabilities in fulfilling the ever increasing global desire for higher data rates for long as well as short distance communication. In order to achieve reliable communication several error detection mechanisms have so far been implemented using conventional electronics which do not match with the pace of optical processing of digital bits. In this research, implementation of the encoding of (7, 4) Cyclic Redundancy Check (CRC) code using optical method has been shown. The CRC encoder has been designed using Lithium Niobate (LiNb03) waveguide based Mach-Zehnder Interferometers (MZI). The structure simulated using beam propagation method has shown accurate encoding of the CRC code. The design parameters as well as the performance parameters have been described briefly.

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.

We present the design of a 2&times;2 photonic switch operating at 1.55-&mu;m wavelength using electro-optic (EO) polymer waveguides. A Mach-Zehnder interferometer (MZI) is used to implement the proposed switch in which two identical 2&times;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&times;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&times;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.

Electro-optic (EO) polymer modulators with a wide range of thermal stability from −46°Cto95°C for fiber-optic gyroscope applications are reported. The synthesized EO side-chain polymer used has a glass transient temperature (Tg) of 200°C and a large EO coefficient of 25.2pm∕V in a real device measurement. Mach–Zehnder (MZ) intensity and optical phase modulators are implemented based on this high-Tg side-chain EO polymer, exhibiting ∼3.75V half-wave voltage with 1.5cm interaction length and 2.3cm total length at 1.55μm wavelength. The optical fiber-to-lens insertion loss is ∼7.5dB in the MZ interferometers and ∼6dB in the straight waveguides. We examine the long-term thermal stability of these devices and demonstrate their ability to meet the strict requirements of various EO device applications, particularly fiber-optic gyroscopes.

Thin‐film lithium niobate (TFLN) based electro‐optic (EO) Mach–Zehnder modulators (MZMs) have shown their potential for next generation high‐speed optical transmission modules and systems. Unlike modulators on other platforms, most of TFLN based EO MZMs adopt single‐drive push‐pull configuration. It is more attractive to design a differential‐drive and push‐pull compatible MZM, which would not only improve the modulation bandwidth, but also facilitate interfacing with electronic drivers. Here, we demonstrate, to the best of our knowledge, the first differential‐drive push‐pull EO modulator on TFLN using a two‐segment MZM structure. By compensating the delay mismatch between optical and microwave signals, the fabricated differential‐drive modulator features an ultra‐low Vπ of 670 mV and a large extrapolated EO bandwidth of ≈109 GHz. This corresponds to, so far, the best voltage‐bandwidth‐ratio performance of ≈243 GHz/V2 for TFLN modulators. Both intensity and coherent modulators are built using the proposed structure, and high‐speed data transmissions are also demonstrated. This differential‐drive MZM structure could promote co‐packaging of TFLN based modulators with electronic chips.

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

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

Titanium-diffused lithium niobate (Ti:LiNbO3) waveguides are widely used in current fiber optic networks because of their high-speed, electro-optic modulation, and low-loss integration with standard single-mode fibers. However, they cannot achieve small ring resonators owing to their lack of a high core-to-cladding index contrast. To overcome this challenge, we vertically integrate an emerging chalcogenide glass waveguide technology on well-established Ti:LiNbO3 waveguides. We present, to our knowledge, the first arsenic trisulfide (As2S3) race-track ring resonator with a 290.8 μm bend radius in an all-pass filter configuration, integrated on a Ti:LiNbO3 waveguide. Vertical coupling is achieved using a unique taper design. Experimental results are shown for 10.6% coupling, 2.08 dB roundtrip loss, and a 25.4 GHz free-spectral range.

A single-optic-fiber temperature and pressure sensor based on a side-polished optical fiber microcavity coated with a polydimethylsiloxane (PDMS) film has been proposed and fabricated. This sensor integrates two Mach-Zehnder interferometers (MZIs), where the first MZI is formed by path 1 in the inside coating, and the second MZI is constructed by path 1 and path 2 in the waist region. The formation mechanism of the dual MZIs is simulated by using the finite-difference beam propagation method, and the sensitivities of the dual MZIs are predicted by simulations. Experimental results indicate the temperature sensitivity of –1.19 nm/℃ for the first MZI and pressure sensitivity of –3.96 nm/MPa for the second MZI, respectively. By monitoring the dual wavelength shifts corresponding to the dual MZIs, temperature and pressure can be simultaneously measured. Due to the good sensitivities, simple fabrication and robust structure, the proposed sensor shows promising potential for optofluidic sensing and ocean detection.

Electro‐optic (EO) Mach‐Zehnder modulators (MZMs) featuring high modulation efficiency and wide bandwidth are essential for large‑capacity optical communication systems. To date, thin‐film lithium niobate (TFLN) MZMs have emerged as a promising solution owing to the exceptional EO bandwidth and compactness, and thus significantly reduced capacitance. However, integrated TFLN MZMs are still several millimeters to centimeters in path length due to the limited modulation efficiency determined by the suboptimal confinement of the electric and optical fields. This limitation hinders large‐scale integration for parallelization or multiplexing and prevents the economically efficient co‐integration with compact electronics. Here, this challenge is overcome by merging sub‐wavelength plasmonic slot waveguides with the TFLN platform to form a strong field confinement below the diffraction limit of optics, and enhance EO overlap and light‐matter interactions. A record‐high modulation efficiency of 0.070 V cm is demonstrated with an ultra‐short length of 15 µm. This plasmonic TFLN MZM exhibits a 3‐dB EO bandwidth exceeding 110 GHz that allows for transmitting 110 Gbaud binary phase‐shift keying signals with a bit error ratio of 2.5 × 10 −5 . This demonstrated plasmonic TFLN MZM provides a promising solution to future ultra‐high‐speed and large‐scale photonic integrated systems for optical interconnections, optical computing, and optical sensing functions.

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

In this paper, an all-fiber novel fabricated Mach-Zehnder interferometer (MZI) based on refractive index (RI) sensor is presented and simulated. This RI sensor is composed of a single-mode fiber (SMF) with a core diameter of 9 μm and a multimode fiber (MMF) with a core diameter of 105 μm. The microgroove can be etched by femtosecond laser or ground by grinding machine technology. It greatly reduces the limitations of structure fabrication. The RI response of this sensor is obtained by beam propagation method. In the range of 1.33-1.334 RIU, the RI sensitivity is -10373 nm/RIU and the linearity is 99.98% by wavelength demodulation. The intensity demodulation shows a nonlinear trend, and the sensitivity increases with the increase of RI . The maximum RI sensitivity is -9614 dB/RIU, and the fitting is 98.69%. The structure has the advantages of simple manufacture, high sensitivity and good linearity. It is very suitable for the practical applications of RI sensing with high sensitivity.

As a powerful and efficient algorithm for bidirectional beam propagation analysis, a combination of the beam propagation method (BPM) and the finite element method (FEM) is proposed. Since the FEM is applied only to regions with significant reflected waves, arbitrary waveguide structures can be treated. A perfectly matched layer boundary condition to avoid nonphysical reflections from computational window edges is introduced. To show the validity and usefulness of the approach proposed here, numerical examples for a semiconductor laser facet and a hemispherically-ended optical waveguide connection are presented. © 1999 Scripta Technica, Electron Comm Jpn Pt 2, 82(10): 1–9, 1999

An electrooptic (EO) polymer was used to fabricate phase modulators and Mach-Zehnder modulators on Si wafers. This glassy polymer is from a class of nonlinear, optical materials that have large EO coefficients, low dielectric constants, and small dispersion from dc to optical frequencies. The modulators were fabricated on Si wafers using conventional IC manufacturing equipment. Three polymer layers were deposited: a hard acrylate cladding layer, followed by an EO polymer from Akzo Research, by1 then another cladding layer. The waveguides were photobleached using an IC mask aligner, and microstrip electrodes were formed by gold plating. The active polymer layer was poled2 through the cladding, and waveguide end faces were prepared by cleaving. The Mach-Zehnder modulator was designed so that each arm could be modulated independently with a separate 50-Ω microstrip electrode; the modulator response was measured up to 20 GHz. Data from each type of modulator are presented. These devices illustrate that polymers offer certain advantages over standard inorganic EO materials, such as LiNbO3 and GaAs, in that multilayer integrated optical circuits can be fabricated on top of electronic substrates using processes and equipment that are largely in place for manufacturing integrated circuits.