Interference Switch Research Articles

Synchronous extraction of microwave energy from cavities through a packet of interference switches

Synchronous extraction of energy from cavity resonators for X-band microwave radiation through a compact packet of five interference switches based on H tees has been experimentally analyzed. It is shown that switches can be completely synchronized and the synchronization conditions are determined. Microwave pulses have been generated upon synchronous extraction of energy from five single-mode cavities (power ∼0.8 MW, gain ∼12 dB, and width ∼3.2 ns) and from one superdimensional cavity (power ∼2.2 MW, gain ∼16.5 dB, and width ∼3.5 ns). The operation limits of X- and S-band microwave compressors with extraction of energy through a packet are estimated.

Charging of the Traveling Wave Resonator of the Microwave Compressor by a Relativistic S-Band Magnetron

The charging of the traveling wave resonator (TWR) of a microwave compressor by a relativistic S-band magnetron that generates microwave pulses with power ≤ 250 MW and duration of ~ 100 ns is described. The short pulse duration determining the resonator charging time and traveling electromagnetic wave increases the electric strength of the resonator. The short duration of the input pulse determines the coupling and Q-factor of the TWR, and it is not necessary to apply an interference switch for energy release. A scheme for releasing energy at a microwave power of ≥ 1 GW using a ferrite circulator is discussed.

Resonant microwave pulse compressor operating in two frequencies

A resonant microwave pulse compressor with a hybrid (Magic) waveguide tee as an interference switch was studied in numerical simulations and experimentally. In this compressor, the necessary condition for energy storage in the compressor cavity is frequency-independent, so that its operation in different cavity eigenmodes without mechanical tuning is possible. An S-band compressor operating in two different frequencies (neighboring modes) was investigated. Two characteristic geometries corresponding to different regimes of the microwave energy accumulation and release were tested using input pulses of 200–400 kW power, 2.4 μs duration, and variable frequency, 2.8 to 2.9 GHz. The geometries are characterized by an RF electric field in the interference switch that is higher or lower than the field in the cavity. The plasma discharge that switches the phases of compressor operation from energy storage to release was initiated by small metallic cones placed in the appropriate location. For both geometries, the nanosecond output pulses in two resonant frequencies were obtained; the maximal peak output power measured was ∼1.8 MW. The efficiency of the microwave extraction was limited by either an insufficient coupling to the tee output arm (in the case of a high field in the tee) or non-uniformity of the plasma discharge (in the case of low field in the tee).

Microwave-energy extraction from a resonator via oversized interference switch

We have studied an interference switch based on an oversized H-plane rectangular waveguide T-junction. Conditions necessary for effective operation of the switch as an energy extractor are evaluated. Microwave pulses of 3.5-ns duration with 2.8-MW power at a gain of 17.5 dB have been obtained using a prototype microwave compressor for the 3-cm waveband with a 72 × 34 mm2 waveguide resonator and a 58 × 25 mm2 waveguide switch. It is shown that, using the proposed switch, it is possible to obtain RF pulses with a power of up to ∼0.1 GW in the 3-cm band and ∼1 GW in the 10-cm band.

Demonstration of a Plasmonic MMI Switch in 10-Gb/s True Data Traffic Conditions

We report the first experimental performance evaluation of a 75-μm-long plasmonic multimode interference switch that is hetero-integrated on a silicon-on-insulator platform, operating with 10-Gb/s data signals. The switch exhibits a 2.9-μs response time and 44.5% modulation depth, while the extinction ratio between the ports alters from 5.4 to -1.5 dB for 35-mW electrical (switching) power. Error-free performance was achieved.

A thermo-optic multimode interference switch structure based on vinyltriethoxysilane (VTES) hybrid organic–inorganic sol–gel

A vinyltriethoxysilane (VTES) based hybrid organic–inorganic sol–gel is synthesized and characterized for its abilities in optoelectronic applications. The resulted hybrid material, which is known as VTT, is fabricated as a thin film structure under controlled environment. The film thickness for various coating speeds and refractive index are measured by the method of prism coupling. Based on the film characterization results, a 2×2 multimode interference photonic switch structure based on thermal controlling effect is proposed. A ridge waveguide of VTT in silica clad is used as a design structure. The switching characteristics due to changes in effective index are analyzed by the two-dimensional finite difference beam propagation method with transparent boundary condition. The proposed structure works well with low crosstalk level of −28dB and low switching power relatively to the structural upper cladding thickness.

Crosstalk Improvement of Polymer in Glass Thermo-Optical Multimode Interference Switch

A new structural design of combined variable optical attenuator (VOA) and optical switch has been proposed in this paper. The design is based on the multimode interference (MMI) architecture and it has been demonstrated for crosstalk improvement of optical switch. The device operates by manipulating thermo-optic (TO) effect that naturally existed in all optical waveguide material. By applying a polymer on glass material platform, the optimized VOA with optical attenuation of 21.52 dB has been achieved with applied power of 36.4 mW. The simulation result shows that the VOA helps to achieve significant improvements of optical switch performance particularly in crosstalk reduction up to 89.66%

Crosstalk Improvement of Polymer in Glass Thermo-Optical Multimode Interference Switch

Crosstalk Improvement of Polymer in Glass Thermo-Optical Multimode Interference Switch

Modeling of a compact and completely non-blocking 4 × 4 multimode interference switch for optical communication applications

Modelling of a compact and completely non-blocking 4×4 optical switch utilizing integrated multi-mode interference (MMI) waveguides with a channel profile of Ti-indiffused Lithium Niobate is described. Design novelty lies in its satisfactory operation for two wide optical windows (100 nm each), with center wavelengths (λcentre) of 1.3 and 1.55 µm, possessing low losses. For either of these windows, the average value of propagation losses are maintained lower than 1 dB with a vacillation of extremely low polarization dependent losses ( ≤ 0.15 dB). Index tuned regions are optimized to achieve average crosstalk levels better than −19 and −12 dB for its operation in the wavelength range of 1.25 to 1.35 µm and 1.50 to 1.60 µm, respectively. It is also observed that switch possess absolute loss uniformity (of the range of 0.5% to 1.6%) with a maximum of ±2.5% tolerance in the structural parameters.

Crosstalk Improvement of Polymer in Glass Thermo-Optical Multimode Interference Switch

Crosstalk Improvement of Polymer in Glass Thermo-Optical Multimode Interference Switch

All-Optical Multi-Mode Interference Switch Using Non-Linear Directional Coupler as a Passive Phase Shifter

This article presents an all-optical multi-mode interference switch in which the non-linear directional coupler is utilized to realize a passive phase shifter. The proposed structure can be used either as a 1 × 2 or a 2 × 2 switch, with two inputs applied simultaneously in the latter case. The operation of the device is mainly based on the phase difference of the inputs of the multi-mode interference section. The beam propagation method is used for the design and simulation of the structure. The simulation results approve the low sensitivity on wavelength and fabrication tolerances. The crosstalk of the structure is equal to −31.6 dB.

Research of high speed optical switch based on compound semiconductor

High-speed optical switch and its array are the crucial components of all-optical switching system. This paper presents the analytical model of a total-internal-reflection (TIR) optical switch. By employing the carrier injection effect in GaAs and the GaAs/AlGaAs double heterojunction structure, the X-junction TIR switch and the Mach-Zehnder interference (MZI) switch are demonstrated at 1.55 µm. The measured results show that the extinction ratio of both switches exceeds 20 dB. The switching speed reaches the scale of 10 ns.

A study of the switching of the microwave compressor switch in a circular waveguide

Results of the experimental study of the interference switch for the H11 mode in a circular 10-cm-wavelength waveguide are presented. The conditions required for efficient microwave discharge switching of the interference switch are determined. The results of the study of the switching process allowed us to design and produce an interference switch with better characteristics than those of rectangular waveguides. It is shown that this switch extracts the stored energy from the microwave compressor cavity more efficiently and improves the amplitude stability of the output pulse radiation.

Multimode interference photonic switches

Photonic switches are becoming key components in advanced optical networks due to their various applications in optical communication. One of the key advantages of photonic switches is the fact that they redirect or convert light without any optical to electronic conversions and vice versa. As one type of optical switch, multimode interference (MMI) switches have received more attention in recent years due to their significant role. The structure and operation principle of various types of MMI switches are introduced, and the recent progresses of MMI switches are also discussed.

Thermo-optic multimode interference switches with air and silicon trenches

A novel thermo-optic multimode interference (MMI) switch with air and silicon trenches was proposed, and the performance of the switch was simulated. In the design, one heating electrode is used to alter the refractive index at a spot image which changes the phase of this image to realize the switching function. The simulation results clearly indicate that the MMI switch can satisfy −39 dB crosstalk at two states. The electric power consumption for the MMI switch with these trenches is less than half of that of a conventional MMI switch.

Studying a gas-discharge switch of a high-power microwave compressor

The results of a study of a high-pressure gas-discharge switch with a blown-through discharge gap are presented. This switch is designed for controlling the energy-storage and-extraction processes in a high-power resonance microwave compressor operating in the 10-cm wavelength region. The dependences of the amplitude stability of the compressor output pulses on the level of the switched power, pulse repetition rate, pressure of the insulating gas, composition of the gaseous mixture (N2 and SF6), blowing-through rate, and features of the discharge-gap configuration are presented. A version of the switch design with a high junction attenuation (∼40 dB) of the compressor’s interference switch, which operates at a switched power of ∼160 MW at a maximum switching power of 200 Hz and an rms deviation of the output-signal amplitude of ∼2–5%, is given.

Low electric power drived thermo-optic multimode interference switches with tapered heating electrodes

A novel thermo-optic multimode interference (MMI) switch with a tapered heating electrode was proposed and the performance of the switch was simulated. An analytical steady-state heat-conduction model is also presented. In the design, one tapered heating electrode is used to alter the refractive index in the multimode slab region to realize the switching function. The simulation results indicate that the MMI switch can provide high extinction ratio, and good polarization- and wavelength-independence. The electric power consumption for the MMI switch is half of that of a switch with a straight heating electrode and similar to that of a Mach–Zehnder interferometer switch.

Multimode interference switch design with loose manufacturing tolerance

Waveguide Solutions6125 Lakeview Road, Suite 200Charlotte, North Carolina 28269E-mail: pjmoyer@email.uncc.eduAbstract. We present a design and simulations for a low power con-sumption, low manufacturing tolerance optical switch for integrated pho-tonic lightwave circuits (PLC). The design is applicable to all materialplatforms, including silicon, lithium niobate, indium phosphide, glass,polymer, sol-gel, and gallium arsenide, just to name a few. The mecha-nism is one that functions by altering the index of refraction in the multi-mode slab region of a multimode interference splitter via the thermo-optic or electro-optic effect. The design is unique in that the electrodesare distributed to maintain multimode behavior, which 1. renders the de-vice easy to manufacture via very loose tolerances, and 2. allows themultiple modes to vary adiabatically so as to maintain efficient opticalpower switching. The power consumption is only about four times higherthan that of a Mach-Zehnder interferometer switch, and it requires muchless tolerance in manufacturing.

Low-light-level nonlinear optics with slow light

Electromagnetically induced transparency in an optically thick, cold medium creates a unique system where pulse-propagation velocities may be orders of magnitude less than $c$ and optical nonlinearities become exceedingly large. As a result, nonlinear processes may be efficient at low-light levels. Using an atomic system with three, independent channels, we demonstrate a quantum interference switch where a laser pulse with an energy density of $\sim23$ photons per $\lambda^2/(2\pi)$ causes a 1/e absorption of a second pulse.

Single-mode rib polymer waveguides and electro-optic polymer waveguide switches

Mode-matching and effective index methods are used to analyze single-mode operation of optical rib polymer waveguides. Their single-mode waveguiding conditions are determined. Single-mode rib waveguides fabricated from guest–host polyetherketone are presented. The estimated propagation loss of straight rib-waveguides is 0.7 dB/cm at 1.55 μm. Furthermore, by using the mode field-transfer matrix method, 2×2 and 4×4 polymer Mach–Zehnder interference switch operating at 1.55 μm wavelength has been designed based on optical multi-mode interference.