Mach-Zehnder Interferometer Optical Switch Research Articles

Polycrystalline silicon 2 × 2 Mach-Zehnder interferometer optical switch.

In this paper, we demonstrate a broadband Mach-Zehnder interferometer optical switch based on polycrystalline silicon (poly-Si), which enables the development of multilayer photonics integrated circuits. The poly-Si is deposited under a low temperature of 620 °C to avoid unexpected thermal stress and influence on optoelectronic performance. By introducing a π/2 phase shifter and a push-pull configuration, the switch achieved low power consumption and loss caused by carrier plasma absorption (CPA). The switch operates effectively in both "Bar" and "Cross" states at voltages of -3.35 V and 3.85 V. The power consumptions are 7.98 mW and 9.39 mW, respectively. The on-chip loss is 5.9 ± 0.4 dB at 1550 nm, and the crosstalk is below -20 dB within the C-band. The switch exhibits a 10%-90% rise time of 7.7 µs and a 90%-10% fall time of 3.4 µs at 1550 nm. As far as we know, it is the first demonstration of a poly-Si switch on an 8-inch wafer pilot-line. The low-temperature deposited poly-Si switch is promising for multilayer active photonic devices and photonic-electronic applications.

Digitally tunable optical delay line based on thin-film lithium niobate featuring high switching speed and low optical loss

A tunable optical delay line (ODL) featuring high switching speed and low optical loss is highly desirable in many fields. Here, based on the thin-film lithium niobate platform, we demonstrate a digitally tunable on-chip ODL that includes five Mach–Zehnder interferometer optical switches, four flip-chip photodetectors, and four delay-line waveguides. The proposed optical switches can achieve a switching speed of 13 ns and an extinction ratio of 34.9 dB. Using a modified Euler-bend-based spiral structure, the proposed delay-line waveguide can simultaneously achieve a small footprint and low optical propagation loss. The proposed ODL can provide a maximum delay time of 150 ps with a resolution of 10 ps and feature a maximum insertion loss of 3.4 dB.

Operating performance of silicon photonic optical switches integrated with WDM filters for low-latency edge-computing platforms

We investigated the performance of a silicon photonic device integrating pn-junction-type Mach-Zehnder interferometer optical switches with wavelength-division-demultiplexing and multiplexing (WDM-DEMUX and MUX) filters that perform switching operations to transmit packet data between edge computing. After separating the 1535 and 1565 nm signals with the Mach-Zehnder delay interferometer-type WDM-DEMUX/MUX filters, cascaded dynamic switching operation with a few nanoseconds turn-on/off for On-Off keying (OOK) signals at 10 Gbps were achieved. The power penalty difference between the input and output was within 0.5 dB for 1565-nm signals. We also verified the switching operation at a bit rate of 25 Gbps and observed clear eye openings.

Scalability of Multi-Stage Nested Mach-Zehnder Interferometer Optical Switch with Phase Generating Couplers

Scalability of Multi-Stage Nested Mach-Zehnder Interferometer Optical Switch with Phase Generating Couplers

Ultrafast Silicon MZI Optical Switch With Periodic Electrodes and Integrated Heat Sink

The compact, high-speed, low-power consumption Mach-Zehnder interferometer (MZI)-type optical switch using thermo-optical effect is a key device in future optical integrated circuits. In this study, we achieved ultra-high-speed switching operation of 0.4 μs and low electrical power operation of 23 mW with a small device footprint by loading an asymmetric doped MZI structure and an integrated heat sink. This optical switch can be fabricated in the standard manufacturing process of silicon photonic devices, has high practicality and will be a useful tool in various optical integrated circuits.

Performance comparison of all-optical logic gates using electro-optic effect in MZI-based waveguide switch at 1.46 µm

Abstract Nowadays to process information on high speed and to reduce the complexity of digital devices, optical digital computational techniques are required. Many complex signal processing functions such as multiplexing, optical switching, addressing, coding/decoding are implemented using optical digital computational techniques. Optical logic gates are one of the most essential computational elements to design combinational and sequential circuits in optical signal processing. In this paper, all optical logic gates are designed with optimized structure of 2 × 2 Mach–Zehnder interferometer optical switch using Ti:LiNbO3 based waveguide at 1.46 µm employing electro-optic effect. Different design structures to realize all-optical logic gates are presented and compared with the previously designed optical logic gates. The mathematical description of all optical logic gates using cascaded structure of Mach–Zehnder interferometer switch is also defined. The performance parameters of designed optical logic gates have been analyzed by beam propagation method and the obtained results are verified by MATLAB.

Nested Mach–Zehnder interferometer optical switch with phase generating couplers

In reconfigurable optical networks, an optical switch is indispensable to afford routing optical signals without optical/electrical conversion. A nested Mach–Zehnder interferometer (MZI) optical switch is suitable for a silicon-silica hybrid structure compared with a conventional cascaded MZI switch. We proposed to employ phase generating couplers (PGCs) instead of directional couplers (DCs) in the nested MZI optical switch. Calculation results show that the nested MZI switch with PGCs exhibits <−30 dB crosstalk over wider wavelength range than that using DCs.

Resonator fiber optic gyros with light time-division input and multiplexing output in clockwise and counterclockwise directions

A resonator fiber optic gyro with the light time-division input and multiplexing output (TDM-RFOG) in the clockwise (CW) and counterclockwise (CCW) directions is proposed. The light time-division input in the CW and CCW directions can effectively suppress the backscattering induced noise. The TDM-RFOG is implemented with the 2 × 2 Mach–Zehnder interferometer (MZI) optical switch. The response time of the fiber ring resonator is analyzed, and it is demonstrated by experiments that light time-division input in the CW and CCW directions can reduce the backscattering induced noise. The suppression effectiveness of backscattering induced noise in the TDM-RFOG is determined by the extinction ratio of the optical switch, so a closed loop is designed to adjust the phase shift difference between the two arms of the MZI optical switch to control the extinction ratio. The method using two arms of the MZI optical switch with twin 90° polarization-axis rotated splices is proposed to make the extinction ratio along both slow and fast axes greater than −70 dB.

Monitoring and automatic tuning and stabilization of a 2×2 MZI optical switch for large-scale WDM switch networks.

Large-scale optical switch networks employ wavelength division multiplexing to expand and facilitate multiple input and outputs. Such networks can be implemented with the Mach-Zehnder interferometer (MZI) as the building block. A fully-loaded MZI switch, meaning one with two optical signals at its two inputs and one that is capable of simultaneously switching those inputs to its two outputs, reduces the number building blocks within the network, and as a result makes them more power and area efficient. However, for practical operation, such MZI switches need to be automatically controlled for overcoming fabrication and thermal variations. We present an interference-based monitoring method that enables automatically switching, tuning, and stabilizing of a fully-loaded 2×2 MZI optical switch and demonstrate a prototype on an SOI platform. Using the proposed device and off-the-shelf electronics, we demonstrate automatic tuning and stabilization of an MZI switch with 12.5 Gb/s and 25 Gb/s data rates and channel spacing as small as 1 nm.

Ultra-power-efficient 2 × 2 Si Mach-Zehnder interferometer optical switch based on III-V/Si hybrid MOS phase shifter.

We have demonstrated an ultra-power-efficient 2 × 2 Si Mach-Zehnder interferometer optical switch with III-V/Si hybrid metal-oxide-semiconductor (MOS) phase shifters. The efficient low-loss phase modulation enables low-crosstalk and broadband switching in conjunction with multimode interference couplers consisting of tapered input and output ports. Owing to the negligible gate leakage current in the hybrid MOS capacitor, the power consumption required for switching is 0.18 nW, approximately 107 times smaller than that of a Si thermo-optic phase shifter. We also demonstrated a switching time of less than 20 ns. The III-V/Si hybrid MOS phase shifter is promising for fabricating large-scale Si photonic integrated circuits that require efficient, low-loss, and high-speed optical phase control.

Polarization-independent and colorless switching operation of three-dimensional 4 × 4 polymer optical switch with two-layered waveguide structure

We fabricated a three-dimensional (3D) 4 × 4 polymer optical interconnection switch with a two-layered waveguide structure equipped with four Mach–Zehnder interferometer optical switches (MZ-OSs), two vertical directional couplers (VDCs), and a multimode interferometer (MMI) coupler. The experimental result for the device shows polarization-independent and colorless switching operation by the thermo-optic (TO) effect in the 1550-nm-wavelength range with a switching power of about 18 mW.

Ultra-compact, self-holding asymmetric Mach-Zehnder interferometer switch using Ge&lt;sub&gt;2&lt;/sub&gt;Sb&lt;sub&gt;2&lt;/sub&gt;Te&lt;sub&gt;5&lt;/sub&gt; phase-change material

An asymmetric Mach-Zehnder interferometer optical switch using phase-change material (PCM) is reported. In this switch, two Ge2Sb2Te5 thin films, each 1 µm in diameter, are deposited on a Si waveguide, and are used as phase shifters. The PCM can be reversibly switched between the amorphous and crystalline states. The difference in refractive index between the two states is very large, typically more than 2. Therefore, an optical switch using the PCM can be very small. The switching operation is successfully demonstrated by laser pulse irradiation. The maximum extinction ratio is 26.7 dB, and 2.2-nm peak wavelength shift is verified.

Large current MOSFET on photonic silicon-on-insulator wafers and its monolithic integration with a thermo–optic 2 × 2 Mach–Zehnder switch

n-channel body-tied partially depleted metal-oxide-semiconductor field-effect transistors (MOSFETs) were fabricated for large current applications on a silicon-on-insulator wafer with photonics-oriented specifications. The MOSFET can drive an electrical current as large as 20 mA. We monolithically integrated this MOSFET with a 2 × 2 Mach-Zehnder interferometer optical switch having thermo-optic phase shifters. The static and dynamic performances of the integrated device are experimentally evaluated.

All-Optical Label Recognition Using Self-Routing Architecture of Mach-Zehnder Interferometer Optical Switches with Semiconductor Optical Amplifiers

We propose a new label recognition system for photonic label switching using self-routing of labels. Binary-coded labels in on-off keying format are considered. The system consists of an all-optical demultiplexer (DeMUX) and an address recognition unit (ARU) consisting of tree-structured switches. The system uses self-routing propagation of an indication bit controlled with address bits. The indication bit is placed in advance of the address bits in the label. In DeMUX, all-optical switches in a configuration of Mach-Zehnder interferometer with semiconductor optical amplifiers (SOA-MZI) are controlled by the indication bit pulse to separate each of the label bits. The indication bit pulse is routed to the destination output port corresponding to the code of the address in ARU. It is shown that all the binary number codes can be recognized with this system. The operation principle is verified by numerical simulation using coupled-mode theory and a rate equation. Moreover, the switching crosstalk is also evaluated.

Theoretical Analysis and Experimental Demonstration of Switch characteristics of MZI Optical Switch Based on SOAs

In this paper we propose a Mach-Zehnder interferometer (MZI) optical switch based on Semiconductor Optical Amplifiers (SOAs) for all-optical 2R regeneration. Detailed investigations are presented on the characteristics of switching window of this device. Numerical simulation and experimental demonstration indicate the width of the optical pulse and the time delay between the input optical signals are essential parameters for a good performance of the device.

A siloxane polymer lightwave circuit on ceramic substrate applicable to ultrafast optoelectronic multi-chip-modules

Technique for integrating optical waveguide circuits on electrical circuits is developed toward the application to opto-electronic multi-chip modules (O/E-MCM), which enables one to handle ultrafast lightwave pulses and electrical signals on a common circuit board. We use ceramic material as the substrate of O/E-MCM having a multi-layer structure. A siloxane polymer is utilized to form low loss optical waveguides on ceramic substrates by low temperature processes. The waveguide has shown high transparency around 1310 nm. The group velocity dispersion has been measured and shown to become almost zero at wavelength of 1310 nm and about 0.4 fs/cm nm at 1550 nm. An optical circuit has been formed on simple electrical circuit consisting of a thermometer film resistance layer. A Mach–Zehnder interferometer optical switch exhibiting the waveguide extinction ratio of 30 dB, control power of 5 mW, and switching speed of 6 ms has been demonstrated. Thermal management characteristics also have been demonstrated successfully. This single-mode optical waveguide can thus be formed readily on ceramic substrates involving electrical circuit layers; this result confirms its applicability to O/E-MCM.