Microring Resonator Devices Research Articles

Mitigation of nonlinearities in long-haul DWDM soliton-based communication system

Abstract The ongoing challenge of research and development is focusing on increasing the overall capacity of the transmission medium, achieving a high bit rate, and designing long-haul optical communication systems. The main requirement of the transmission system in supporting high bit rates in optical communication systems is their tolerance to nonlinear fiber impairments. Optical soliton pulses that preserve their shape over long distances are the straightforward solution to this problem. In this paper, DWDM soliton-based optical communication system is designed to mitigate the nonlinear effects at a data rate of 10 Gbps with channel spacing of 100 GHZ by using a microring resonator (MRR) device which acts as an add/drop filter that generates a filter narrowband wavelength from a wider optical spectrum. The transmission link of the optical fiber has a total length of 180 km and MRR is inserted at the end of the loop which provides the required bandwidth. The high bit rate signals can be transmitted through this MRR system to get the filtered signal which is less affected by the nonlinearities. This filtered signal is observed at a total transmission distance of 54,000 km. Also, by using dispersion compensation techniques, the impact of four-wave mixing (FWM) is mitigated. The performance of the designed system is evaluated based on the quality factor (Q-factor) along with the bit error rate (BER) obtained.

Embedded racetrack microring resonator sensor based on GeSbSe glasses.

In this article, a compact racetrack double microring resonator (MRR) sensor based on Ge28Sb12Se60 (GeSbSe) is investigated. The sensor device consists of a racetrack microring, an embedded small microring, and a strip waveguide. Electron beam lithography (EBL) and dry etching are used to fabricate the device. The compact racetrack double MRR device are obtained with Q-factor equal to 7.17 × 104 and FSR of 24 nm by measuring the transmission spectrum. By measuring different concentrations of glucose solutions, a sensitivity of 297 nm/RIU by linear fitting and an intrinsic limit of detection (iLOD) of 7.40 × 10-5 are obtained. It paves the way for the application of chalcogenide glasses in the field of biosensing.

Micro-Ring Resonator Devices Prototyped on Optical Fiber Tapers by Multi-Photon Lithography

Multi-photon lithography -a powerful laser nanoscale additive-manufacturing method- is employed for structuring micro-ring traveling-wave resonators onto micrometric diameter, optical fiber tapers. These weakly guided, micro-ring resonating structures achieve light circulation with Q-factors of the order of ∼2.0 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> , for typical diameters of tens of micrometers, in the spectral band of 1550 nm. The parametrization of the fabrication process, the characterization of these structures in TE and TM polarization, and the numerical simulation of their spectral performance is presented and analyzed. Moreover, these micro-ring resonators are exemplified into the demonstration of an ethanol vapor sensor, readily achieving detectivities of 0.5 ppm, based on reversible physisorption effects. Our demonstration aims at developing a new type of photonic platforms, based on a versatile, laser based prototyping approach onto micrometric size, optical fiber tapers, while exhibiting unique guiding and modal interaction characteristics, for departing the laboratory bench, while being implemented into diverse types of sensing and actuating devices.

4-Bit All-Optical Serial-to-Parallel Converter With Sub-dB/cm Delay Lines Based on Rib Waveguides

This paper extends our previous work on the microring resonator-type serial-to-parallel conversion scheme aimed for all-optical label processing on the silicon photonic platform. In the previously proposed scheme, the architecture of the delay lines was silicon wires. This resulted in considerable propagation loss, confining multibit operation of serial-to-parallel conversion to a label packet of 2 bits. However, during a practical application, propagation loss at the delay lines has to be improved to support label packets comprising of a greater number of bits. The purpose of this article is twofold. First, we confirm that propagation loss can be lowered to sub-dB/cm values by introducing rib waveguides via simulations and experiment. Second, we demonstrate multibit serial-to-parallel conversion on a 4-bit label “1101” by utilizing a cascaded microring resonator device of which the straight sections of the delay lines are of rib waveguide architecture. In order to focus on free-carrier dispersion effect of silicon during operation, we left out a temporal delay between the pump pulses and probe bits to be extracted. As a result, serial-to-parallel conversion was viable even at peak pump power levels as low as ∼100 mW. We hereby verify that the proposed serial-to-parallel conversion scheme incorporated with rib waveguide delay lines is a realistic solution in realizing a photonics-based solution to all-optical label processing.

Enhanced Sensitivity of Microring Resonator-Based Sensors Using the Finite Difference Time Domain Method to Detect Glucose Levels for Diabetes Monitoring

The properties of light and its interaction with biological analytes have made it possible to design sophisticated and reliable optical-based biomedical sensors. In this paper, we report the simulation, design, and fabrication of microring resonator (MRR)-based sensors for the detection of diabetic glucose levels. Electron Beam Lithography (EBL) with 1:1 hydrogen silsesquioxane (HSQ) negative tone resist were used to fabricate MRR on a Silicon-on-Insulator (SOI) platform. Scanning Electron Microscopy (SEM) was then used to characterize the morphology of the MRR device. The full-width at half-maximum (FWHM) and quality factors of MRR were obtained by using a tunable laser source (TLS) and optical spectrum analyzer (OSA). In this paper, the three-dimensional Finite Difference Time Domain (3D FDTD) approach has been used to simulate the proposed design. The simulation results show an accurate approximation with the experimental results. Next, the sensitivity of MRR-based sensors to detect glucose levels is obtained. The sensitivity value for glucose level detection in the range 0% to 18% is 69.44 nm/RIU. This proved that our MRR design has a great potential as a sensor to detect diabetic glucose levels.

Low-Power-Consumption Integrated Tunable Filters for WDM Switching Applications in Silicon Photonics

We present the experimental results of thermally tunable double microring resonator devices for integrated wavelength division multiplexing applications. The devices demonstrated a free-spectral range up to 2.4 THz (19.2 nm) around 1550 nm and a channel rejection higher than 35 dB. Using Ti/TiN metal heaters, a power consumption of 20 mW per FSR per ring is achieved, which outperformed analogous devices fabricated using the standard silicon process. A thermal tuning efficiency of 0.95 nm/mW is accomplished, and a symmetric tuning is obtained with less than 1% of electrical compensation.

Optical analogue between relativistic Thomas effect in special relativity and phase response of the photonic integrated circuits-based all-pass filter

ABSTRACTWe report a link (or optical analogue) between the relativistic Thomas rotation angle effect found in the special theory of relativity (STR), and the phase response of an all-pass filter (APF), one of the building blocks of the rapidly evolving field of photonic integrated circuits. This link opens up the possibility of investigating STR phenomena in a ‘laboratory-on-a-chip’ setting. The Thomas effect is a spatial rotation of the reference frame due to Einstein’s velocity addition law of two successive velocities travelling in non-collinear directions. On the other hand, the APF is implemented with a microring resonator device with one waveguide bus. The analogue is established by associating two parameters. First, the transmission coupling coefficient τ of the APF is made to equal with the product of the two relativistic normalized velocities V1 and V2 (τ = V1V2), where the normalized velocities V1 = tanh [β1/2] and V2 = tanh [β2/2] with β1 (=tanh−1 (v1/c)) and β2 (=tanh−1 (v2/c)) being the rapidity values associated with the standard normalized speed. Second, the single-pass phase shift φ (or equivalently the phase detuning, Δφ or wavelength detuning, Δλ) parameter of the APF is related to the so-called generating angle θ of the two non-collinear relativistic velocities V1 and V2. We also introduce an additional photonic circuit to convert this phase-encoded Thomas angle into intensity for direct measurement. Lastly, other important and broader consequences of this link are briefly discussed.

Crosstalk in SOI Microring Resonator-Based Filters

We experimentally investigate the interchannel and intrachannel crosstalk of first- and second-order microring resonator (MRR) filters fabricated on a silicon-on-insulator platform. We find that there is an MRR radius that maximizes the wavelength division multiplexing channel count given a waveguide geometry, a maximum tolerable insertion loss, and a minimum permissible adjacent channel isolation. The measured power penalties due to interchannel crosstalk of two-channel demultiplexers based on first-order and series-coupled MRR filters are presented as functions of channel spacing and adjacent channel isolation. Next, we compare the intrachannel crosstalk of first-order, cascaded, and series-coupled MRR add-drop filters. Our results show that first-order MRR devices are unsuitable for simultaneous add-drop operation at high data rates and small channel spacings. Intrachannel crosstalk of cascaded and series-coupled designs are measured as functions of the data rate and the level of detuning between the MRRs. Low intrachannel crosstalk power penalties are demonstrated for cascaded and series-coupled MRR filters for data rates up to 20 Gb/s. Based on the measured results, we present requirements for the input-to-through response of add-drop filters that will ensure low intrachannel crosstalk.

Fast Wavelength Locking of a Microring Resonator

Microring resonator devices require thermal initialization to match their intended operating wavelengths in a process called wavelength locking. We use the dither technique, where we apply a small periodic signal to the microring's integrated heater, to demonstrate reliable wavelength locking of a microring resonator filter to an operating wavelength at a wavelength shift rate of 0.012 nm/μs, an order of magnitude faster than previous demonstrations. We also identify and characterize fundamental speed limits of the wavelength locking process, showing that the integrated-heater bandwidth is the limiting factor.

基于Kerr效应的微环谐振腔延时器件

The time delay characteristics of microring resonator device based on optical Kerr effect were studied.The coupling coeffecient was calculated by the coupled mode theory.The designed parameters were introduced including the material and component.The radius of microring was 300μm.The sectional dimension was 400×1 000nm2.The controlling methods of time delay was presented.The motivation was large time delay value as much as possible on the condition of less than±5ps ripple.The results show that the delay time is more than 130ps;compensating bandwidth is about 20GHz;free spectral range is 50 GHz;the working wavelength which is 1 550nm satisfies the demand of dense wavelength division multiplexing system.The energy consumption is less than 0.8dBm.The fast operating speed is ps order and small capacity which is less than 3mm2 is great advantages for the device. The devices provide references for the delay lines in all optical communication networks.

Resolving the thermal challenges for silicon microring resonator devices

AbstractSilicon microring resonators have been hailed for their potential use in next-generation optical interconnects. However, the functionality of silicon microring based devices suffer from susceptibility to thermal fluctuations that is often overlooked in their demonstrated results, but must be resolved for their future implementation in microelectronic applications. We survey the emerging efforts that have been put forth to resolve these thermal susceptibilities and provide a comprehensive discussion of their advantages and disadvantages.

Manufacturing Error in the Application of Improving Spectrum for a Vertical Coupling Microring Resonator

All the effects of manufacturing errors on transmission spectrum are analyzed for a vertical coupling microring resonator (MRR). Results show that the core refractive index, core thickness and radius errors of ring result in central wavelength shift of the transmission spectrum, and the central deviation and thickness between the ring and channel lead to nonresonant light intensity change. In order to obtain satisfactory spectrum for a fabricated MRR device, some allowed manufacturing errors are discussed, and the accumulation and compensation of manufacturing errors are investigated.

Effects of manufacturing errors on the characteristics of a polymer vertical coupling microring resonator

The effects of manufacturing errors on transmission characteristics are analyzed for a polymer vertical coupling microring resonator. Calculated results show that the errors cause a shift and shape change of the transmission spectrum compared to the designed case without errors. Furthermore, accumulation and compensation for the errors is researched. In order to realize the normal filtering for the fabricated microring resonator device, some allowed errors are discussed.

Simulation Of Soliton Amplification In Micro Ring Resonator For Optical Communication

A system consisting of a series of micro ring resonator (MRR) is proposed. Optical dark and bright soliton pulses propagating through the nonlinear waveguides are amplified. This system can be used in long distance communication system. The dark and bright soliton is input into the designed system. The nonlinear effect contributes to segregation of continuous soliton pulse into smaller pulses. In this way large bandwidth of optical signals can be obtained. The power amplification occurs when the soliton propagates along the MRRs systems. In this research the concern is the generation of amplified pulse of optical dark and bright soliton while propagating in the MRR device. Simulated results show the amplification of bright soliton in which the input power increases from 0.6 W to 10.9331 W and 7.684 W at the trapped wavelength of 1520.428 nm and 1519.912 nm respectively. Key words: Optical soliton; dark soliton; bright soliton; soliton amplification

A new generate carrier for THz communication by the nonlinear microring resonator systems

This paper presents the simulation results of light pulse traveling within a microring resonator system that have shown the optimize results with various applications. The design system consists of a nonlinear microring resonator system incorporating an add/drop filter. The input is bright soliton pluse, whereas the suitable simulation parameters are input power, pulse width, ring radii are 5-10μm and the material refractive indices (κ) are 0.10-0.97. The potential applications for new technique for THz communication system is 0.19 THz by laser sources from microring and nanoring resonator device.

Coupled spiral-shaped microring resonator-based unidirectional add–drop filters withgapless coupling

In this paper, a new type of coupled spiral-shaped microring resonator-based filter with awaveguide butt-coupled to a spiral notch, which can significantly relax the fabricationconstraints, is reported on. Our two-dimensional finite-difference time-domain calculationssuggest resonance splitting which is due to the strong inter-cavity coupling. The novelspiral ring-shaped filter is found to be operating as a band-pass filter with a many-elementcascaded spiral-shaped microring resonator device. As the number of cascaded microringresonators increases, the lineshapes become inhomogeneously broadened and steeper. Forthe eight-element device, the broadened lineshape results in periodic rejection bands with ∼ 6 nm bandwidth.

Compact Microring Resonator With 2$\,\times\,$2 Tapered Multimode Interference Couplers

Compact microring resonator devices are realized by using a small SU-8 polymer strip waveguide that has an SU-8 polymer core (n ~ 1.573), an SiO2 buffer (n ~ 1.445), and an air cladding. Due to the high index contrast of the optical waveguide, a small bending radius ( ~ 150 mum) is used for the MRR. To enhance the coupling between the access optical waveguides and the microring, 2 times 2 multimode interference couplers are used. The measured spectral response of the through port shows a high extinction ratio of over 15 dB and a 3-dB bandwidth of about 0.38 nm (corresponding to a moderate Q-value of ~ 4500).

QKD and QDC via optical–wireless link for quantum mobile telephone network application

We propose a novel system of the simultaneous continuous variable quantum key distribution (QKD) and quantum dense coding (QDC) using a soliton pulse within the nonlinear micro-ring resonator devices. By using the appropriate soliton input power and nonlinear micro-ring parameters, the continuous signals are generated spreading over the spectrum. The polarized photons are formed by using the polarization control unit incorporating into the micro-ring system, which is allowed the different time slot entangled photon pair randomly formed. Results obtained have shown that the application of such a system for the simultaneous continuous variable quantum cryptography and dense coding within a single system is plausible, which is can be implemented within the mobile telephone hand set and networks.

Microring Resonators Fabrication by BCB Adhesive Wafer Bonding

Microring resonator devices are attractive for Wavelength Division Multiplexing (WDM) applications because of their inherent spectral characteristics. GaInAsP/InP microring resonator devices were fabricated using a vertical integration concept based on GaInAsP/InP-on-GaAs wafer-to-wafer bonding. Different materials and wafer bonding processes were tested. The successful fabrication process was using BCB wafer-to-wafer adhesive bonding.

Microring resonators fabricated by electron beam bleaching of chromophore doped polymers

Decomposition of chromophore molecules under direct electron beam irradiation reduces the refractive index of chromophore containing polymers. The induced refractive index contrast between the exposed and unexposed regions is high enough for waveguide bends of small radius and thus microring resonator devices. This electron beam bleaching of chromophore-containing polymers provides a fabrication approach for nonlinear polymer optical waveguide devices. Fabrication of high quality microring resonators with critical feature size on the order of 100nm was demonstrated with this technique in an electro-optic polymer that contains YL124 chromophores.