Ring Modulator Research Articles

1.6 Tbps Silicon Photonics Integrated Circuit and 800 Gbps Photonic Engine for Switch Co-Packaging Demonstration

We describe the performance of high bandwidth-density silicon photonic based integrated circuits (SiPh ICs) that enable the first fully functional photonic engine (PE) module co-packaged with an Ethernet switch. We demonstrate the 1.6 Tbps SiPh transmitter (Tx) IC that integrates on-die all the lasers, micro ring modulators, monitor photodetectors, spot size converters, and V-grooves that are needed to support sixteen 106.25 Gbps PAM4 optical transmit channels. This SiPh Tx, together with discrete receiver (Rx) SiPh ICs, enabled an 800 Gbps PE. The PE is designed to allow up to sixteen modules to be co-packaged around a high-bandwidth switch ASIC. The PE test results described in this article were obtained using sixteen 53.125 Gbps electrical channels that were multiplexed to drive eight simultaneously operating 106.25 Gbps optical channels. We report DR4 IEEE standards compliant high-speed optical eye performance as well as full link operation. Post-FEC error-free operation over temperature and over extended time duration is demonstrated on all channels.

Assembly of the peripheral stalk of ATP synthase in human mitochondria

The adenosine triphosphate (ATP) synthase in human mitochondria is a membrane bound assembly of 29 proteins of 18 kinds organized into F1-catalytic, peripheral stalk (PS), and c8-rotor ring modules. All but two membrane components are encoded in nuclear genes, synthesized on cytoplasmic ribosomes, imported into the mitochondrial matrix, and assembled into the complex with the mitochondrial gene products ATP6 and ATP8. Intermediate vestigial ATPase complexes formed by disruption of nuclear genes for individual subunits provide a description of how the various domains are introduced into the enzyme. From this approach, it is evident that three alternative pathways operate to introduce the PS module (including associated membrane subunits e, f, and g). In one pathway, the PS is built up by addition to the core subunit b of membrane subunits e and g together, followed by membrane subunit f. Then this b-e-g-f complex is bound to the preformed F1-c8 module by subunits OSCP and F6 The final component of the PS, subunit d, is added subsequently to form a key intermediate that accepts the two mitochondrially encoded subunits. In another route to this key intermediate, first e and g together and then f are added to a preformed F1-c8-OSCP-F6-b-d complex. A third route involves the addition of the c8-ring module to the complete F1-PS complex. The key intermediate then accepts the two mitochondrially encoded subunits, stabilized by the addition of subunit j, leading to an ATP synthase complex that is coupled to the proton motive force and capable of making ATP.

Probing Gordon Mumma's Studio Heuristic through a Digital Recreation of Mesa (1966)

Gordon Mumma (b. 1935) composed and performed music with live electronics alone or in collaboration with such central figures as John Cage, David Tudor, or Robert Ashley. This activity, closely linked to the American experimentalist tradition, grew out of his first youthful electronic essays on the University of Michigan campus, his work in Milton Cohen’s Space Theater beginning in 1957, and then at the ONCE festival from 1961. It was in Ann Arbor, Michigan that Mumma set up his first electronic music home studio, a pioneering effort that was so innovative that Mumma would publish an article on home studio building in the Journal of the Audio Engineering Society in 1964. This paper traces Mumma’s studio heuristic by reporting on the results of a digital recreation project by the author, in collaboration with Francis Lecavalier (programming) and Ofer Pelz (electronic performance), of one of Mumma’s iconic live electronic works, Mesa (1966), for bandoneon and live electronics. By synthesising information culled from an electronics schematic diagram, two recordings of the work, the composer’s contemporaneous writings and published interviews, but most importantly, an email correspondence stretching over the two years that preceded the performance of Mesa at the Montreal New Musics Festival on 27 February 2017, the ‘DIY’ practices of this early live electronic creation come into focus. Mesa’s apparatus involves the following essential elements: 1) ring modulation 2) a gate matrix that only sends signals beyond a given threshold to the effects modules 3) four input channels consisting of two piezo microphones on either side of the bandoneon as well as 4) a corresponding quadraphonic output to four speakers. The author contends that in an open-ended creation like Mesa, the work’s ontology is coeval with the scope of its technical apparatus.

Number-Resolved Photocounter for Propagating Microwave Mode

Detectors of propagating microwave photons have recently been realized using superconducting circuits. However a number-resolved photocounter is still missing. In this letter, we demonstrate a single-shot counter for propagating microwave photons that can resolve up to $3$ photons. It is based on a pumped Josephson Ring Modulator that can catch an arbitrary propagating mode by frequency conversion and store its quantum state in a stationary memory mode. A transmon qubit then counts the number of photons in the memory mode using a series of binary questions. Using measurement based feedback, the number of questions is minimal and scales logarithmically with the maximal number of photons. The detector features a detection efficiency of $0.96 \pm 0.04$, and a dark count probability of $0.030 \pm 0.002$ for an average dead time of $4.5~\mathrm{\mu s}$. To maximize its performance, the device is first used as an \emph{in situ} waveform detector from which an optimal pump is computed and applied. Depending on the number of incoming photons, the detector succeeds with a probability that ranges from $(54 \pm 2)\%$ to $99\%$.

Low-chirp push-pull dual-ring modulator with 144 Gb/s PAM-4 data transmission.

We experimentally demonstrate a low-chirp high-speed push-pull dual-ring modulator. The device is formed by two parallel cascaded add-drop ring modulators which has a Fabry-Perot resonance spectrally similar as electromagnetically induced transparency (EIT) effect. Differential drive signals are applied to the two rings to shift the individual resonances towards opposite directions, creating intensity modulation with suppressed frequency chirp. We present static and dynamic characterization of the device, including chirp parameter. We also demonstrate 144 Gb/s PAM-4 data transmission with 1-km standard single-mode fiber (SSMF) with BER below hard-decision forward error correction (HD-FEC) threshold with 7% overhead.

Macro geometry multi-objective optimization of planetary gearbox considering scuffing constraint

A novel multi-objective optimization of planetary gearbox is presented using a discrete version of Non-Dominated Sorting Genetic Algorithm (NSGA-II). Minimization of weight and total power loss of planetary gearbox are two objective functions. Number of teeth in the sun, planet and ring gears, module, face width, input shaft and planet pin diameter are design variables. Regular mechanical, bearing selection and scuffing are various design constraints considered. Investigations were done for three different gear profiles on an industrial planetary gearbox. The results were compared with an industrial gearbox provided in the AGMA standard, which showed not only significant reduction of weight and power loss, but were also found safer in scuffing. Pareto fronts of different ISO grade oils were compared for all gear profiles, and ISO VG 460 was found to be the best oil. Further analysis without a scuffing constraint showed moderate to high levels of scuffing risk for lower-grade ISO oils and lower level risk for higher-grade ISO oils. Ultimately, this study helps to reduce weight, enhance the efficiency and prevent early failures in planetary gearbox.

Design and Performance Evaluation of Multi-Gb/s Silicon Photonics Transmitters for High Energy Physics

Optical links are rapidly becoming pervasive in the readout chains of particle physics detector systems. Silicon photonics (SiPh) stands as an attractive candidate to sustain the radiation levels foreseen in the next-generation experiments, while guaranteeing, at the same time, multi-Gb/s and energy-efficient data transmission. Integrated electronic drivers are needed to enable SiPh modulators’ deployment in compact on-detector front-end modules. A current-mode logic-based driver harnessing a pseudo-differential output stage is proposed in this work to drive different types of SiPh devices by means of the same circuit topology. The proposed driver, realized in a 65 nm bulk technology and already tested to behave properly up to an 8 MGy total ionizing dose, is hybridly integrated in this work with a lumped-element Mach–Zehnder modulator (MZM) and a ring modulator (RM), both fabricated in a 130 nm silicon-on-insulator (SOI) process. Bit-error-rate (BER) performances confirm the applicability of the selected architecture to either differential and single-ended loads. A 5 Gb/s data rate, in line with the current high energy physics requirements, is achieved in the RM case, while a packaging-related performance degradation is captured in the MZM-based system, confirming the importance of interconnection modeling.

Design, Fabrication, and Evaluation of Polyglycolic Acid Modules with Canals as Tissue Elements in Cellular-Assembly Technology

The aim of the present study was to design and fabricate polyglycolic acid (PGA) modules on the basis of the Raschig ring as a tissue element for bottom–top tissue engineering to increase the feasibility of cellular-assembly technology. Three types of modules, namely, cylindrical, Raschig ring, and transverse-pore modules, with different numbers and orientations of canals, were designed and fabricated by modified selective-laser-sintering (SLS) technology. These modules maintained their structure in a flowing culture environment, and degradation did not create an acidic environment, hence promoting their ability to scale up to highly functional tissue. The modules were seeded with human hepatoma Hep G2 cells and cultured for 10 days. The transverse-pore modules were found to have the highest glucose consumption, albumin production, and cell viability among the three tested modules. Our study showed that the proposed module design provided better mass transfer and possessed the required mechanical strength to enable use in the construction of large tissue.

Multiparametric amplification and qubit measurement with a Kerr-free Josephson ring modulator

Josephson-junction based parametric amplifiers have become a ubiquitous component in superconducting quantum machines. Although parametric amplifiers regularly achieve near-quantum limited performance, they have many limitations, including low saturation powers, lack of directionality, and narrow bandwidth. The first is believed to stem from the higher order Hamiltonian terms endemic to Josephson junction circuits, and the latter two are direct consequences of the nature of the parametric interactions which power them. In this work, we attack both of these issues. First, we have designed a new, linearly shunted Josephson Ring Modulator (JRM) which nearly nulls all 4th-order terms at a single flux bias point. Next, we achieve gain through a pair of balanced parametric drives. When applied separately, these drives produce phase-preserving gain (G) and gainless photon conversion (C), when applied together, the resultant amplifier (which we term GC) is a bi-directional, phase-sensitive transmission-only amplifier with a large, gain-independent bandwidth. Finally, we have also demonstrated the practical utility of the GC amplifier, as well as its' quantum efficiency, by using it to read out a superconducting transmon qubit.

Modeling and Optimization of Hybrid FinFET-Silicon Photonic Interconnects

Optical links have emerged as the best solution for short-reach communications (down to tens of meters), both in terms of speed and power consumption. In order to reduce energy-per-bit consumptions and enhance data rates, new technologies (for modulators, packaging, etc.) are being developed.Before implementing them into commercial products, it is essential to evaluate the impact of these new technologies on the overall performance of a link. In this work, a benchmarking tool is developed to optimize the design of electrical transceivers and to minimize the energy-per-bit consumption of a silicon photonic optical link integrated with CMOS FinFET transceivers. This tool is used to compare three stacking technologies (C4 bumps, micro-bumps and bump-less stacking) and evaluate their impacts on an optical link's data rate and power consumption. For this study, a silicon ring modulator is used to modulate the light from a laser, and all components of the link are designed such that a bit-error-rate of $ 10^{-12}$ is achieved. This work shows that replacing conventional C4 bumps by a bump-less stacking interface extends the bandwidth of an optical link from 45 Gbps to 65 Gbps, and reduces the energy-per-bit consumption from 2 pJ/bit to 0.6 pJ/bit at 45 Gbps.

Optimizing Josephson-ring-modulator-based Josephson parametric amplifiers via full Hamiltonian control

Josephson Parametric Amplifiers (JPA) are nonlinear devices that are used for quantum sensing and qubit readout in the microwave regime. While JPAs regularly operate in the quantum limit, their gain saturates for very small (few photons) input power. In a previous work, we showed that the saturation power of JPAs is not limited by pump depletion, but instead by the high-order nonlinearity of Josephson junctions, the nonlinear circuit elements that enable amplification in JPAs. Here, we present a systematic study of the nonlinearities in JPAs, we show which nonlinearities limit the saturation power, and present a strategy for optimizing the circuit parameters for achieving the best possible JPA. For concreteness, we focus on JPAs that are constructed around a Josephson Ring Modulator (JRM). We show that by tuning the external and shunt inductors, we should be able to take the best experimentally available JPAs and improve their saturation power by $\sim 15$ dB. Finally, we argue that our methods and qualitative results are applicable to a broad range of cavity based JPAs.

Microwave power induced resonance shifting of silicon ring modulators for continuously tunable, bandwidth scaled frequency combs.

We demonstrate a technique to continuously tune center frequency and repetition rate of optical frequency combs generated in silicon microring modulators and bandwidth scale them. We utilize a drive frequency dependent, microwave power induced shifting of the microring modulator resonance. In this work, we demonstrate center frequency tunability of frequency combs generated in silicon microring modulators over a wide range (∼8nm) with fixed number of lines. We also demonstrate continuously tunable repetition rates from 7.5GHz to 15GHz. Further, we use this effect to demonstrate a proof-of-principle experiment to bandwidth scale an 8-line (20dB band) comb generated from a single ring modulator driven at 10GHz to a comb with 12 and 15 lines by cascading two and three ring modulators, respectively. This is accomplished by merging widely spaced ring modulator resonances to a common location, thus coupling light simultaneously into multiple cascaded ring modulators.

Improving the Linearity of Silicon Ring Modulators by Manipulating the Photon Dynamics

We demonstrate that the linearity of silicon ring modulators can be improved significantly by manipulating the dynamics of photons in the cavity. A theoretically model is established to analyze the dependence of the modulation linearity on lifetime and wavelength of photons. By reducing Q factors of silicon ring modulators from 11000 to 5880 and tuning the operation wavelength, measured Spurious-Free Dynamic Ranges for the third-order intermodulation distortion are improved from 98.5 dB·Hz2/3 to 104.3 dB·Hz2/3 and from 90.6 dB·Hz2/3 to 94.7 dB·Hz2/3 at 1 GHz and 10 GHz, respectively.

4-channel 200 Gb/s WDM O-band silicon photonic transceiver sub-assembly.

We demonstrate a 200G capable WDM O-band optical transceiver comprising a 4-element array of Silicon Photonics ring modulators (RM) and Ge photodiodes (PD) co-packaged with a SiGe BiCMOS integrated driver and a SiGe transimpedance amplifier (TIA) chip. A 4×50 Gb/s data modulation experiment revealed an average extinction ratio (ER) of 3.17 dB, with the transmitter exhibiting a total energy efficiency of 2 pJ/bit. Data reception has been experimentally validated at 50 Gb/s per lane, achieving an interpolated 10E-12 bit error rate (BER) for an input optical modulation amplitude (OMA) of -9.5 dBm and a power efficiency of 2.2 pJ/bit, yielding a total power efficiency of 4.2 pJ/bit for the transceiver, including heater tuning requirements. This electro-optic subassembly provides the highest aggregate data-rate among O-band RM-based silicon photonic transceiver implementations, highlighting its potential for next generation WDM Ethernet transceivers.

Broadband optical single sideband generation using an ultra high shape-factor self coupled ring resonator

In this study, we realize an integrated generation of optical Single SideBand with Carrier (SSB+C) signal for microwave photonics applications. It has been achieved using a Micro Ring Modulator (MRM) combined with a cavity based wavelength selective filter. MRM, when applied with an RF input, results in a Double SideBand with Carrier (DSB+C) signal where one sideband is suppressed by applying this signal to the filter. The filter has been created using a single resonance-split self-coupled cavity with an extremely high shape factor of 0.69. The sideband suppression ratio between DSB+C and SSB+C ranges from 16 dB to 55 dB for a frequency range of 4 GHz to 20 GHz. Tunable suppression ratio of 21 dB has been achieved at a fixed frequency of 15 GHz. Dynamic range performance of the generated signal has been evaluated at a noise floor of -156 dBm. The dynamic range remains stable in the range of 1 GHz - 5 GHz at ∼ 80 dB.Hz2∕3.

Time Metaphor and Prime Numbers in Anatol Vieru's Symphony No. 5

Time Metaphor and Prime Numbers in Anatol Vieru's Symphony No. 5 Livia Teodorescu-Ciocănea (bio) and Joel Crotty (bio) Introduction We argue that Eminescu's poetry has the potential to generate a distinctive musical aesthetics. Anatol Vieru captured this aspect in his Fifth Symphony and directed it towards an original musical poetics rooted in a series of "key words" from Eminescu's poems, such as: moon, horn, longing, death, ever, comfortless, far away. A unique approach to Eminescu's imagery is the association between the idea of the passing of time and the increase of the distance to the mathematical origin of the prime numbers and their multiples. We also suggest that the metaphor of the deepening in time is also mirrored by the generally augmenting gap between two consecutive prime numbers towards infinity.1 Vieru metaphorically expresses this parallel especially in the first part of his Fifth Symphony, based on the poem "Peste vârfuri"2 (… Mai departe, mai departe, Mai încet, tot mai încet, … [Far away and ever [End Page 43] farther, Softer still, its fading breath …]3). In Vieru's The Book of Modes4 the composer provides the analyst with a few ways into understanding the processes behind his Fifth Symphony, with some emphasis on the first part. Brief commentaries on the other parts of the symphony will complete the presentation: folkloric essence (Part II Colinde, colinde5); symbolistic alliterations (Part III Dintre sute de catarge6) and philosophical statement (Part IV Glossa7). This paper focuses mainly on the first part of the Symphony, based on Eminescu's poem Peste vârfuri, which is rich in philosophical ideas about time, space and loneliness. Our study presents synthetically and in an original graphical manner the mathematical underlying network of the first 97 bars of the first part of the Vieru's Symphony No. 5, revealing the superimposed and interconnected layers of events that metaphorically refer to Eminescu's philosophy of time. The analysis takes into account the use of prime numbers in the organization of chords unfolding and further provides brief observations about rhythmic values and macrostructure, which are also in connection with primes. Over the last one hundred years or so, many composers including Bartók, Schoenberg, Messiaen, Stockhausen, Xenakis, Ligeti, Niculescu, Grisey, and Gubaidulina have developed musical organizational methods that have derived from extra-musical realms, like special applications (formal or metaphorical) of mathematical principles8 such as: the use of symmetry, golden ratio, Fibonacci series, calculus of probability and statistics, magic square, set theory, group theory, fractal theory, etc. Common descriptions of their music may include loose references to physics: centricity9 paralleled with gravity (posttonal or modal and spectral music) or non-centricity (atonal), crowded textures or nonthematical surfaces (see Ligeti's micropolyphony in Requiem) associated with mass, energy, tension. Another inspirational source for composers' musical imagination came from acoustics (waves, spectrum, harmonic/inharmonic spectrum, polyspectrum, etc.), resulting in various forms of spectralism10 (Murail, Grisey, Radulescu) or from psychoacoustics (spectral listening, sensory consonance or dissonance).11 Terms derived from quantum mechanics (fusion or fission) are to be found in musicology, like spectral fusion or spectral fission (Sethares, 2005). A number of procedures used in electronics have inspired composers like Reich, Riley, Adams, Penderecki, Ligeti, Saariaho (loops, synchronization/non synchronization, sound/noise continuum, ring modulation, condensation/rarefaction, etc.). [End Page 44] In his Fifth Symphony (written between 1984–85 and premiered in 1986), Anatol Vieru reveals a method of organizing the occurrence of major and minor triads upon algorithms based on the unfolding of prime numbers and their multiples reduced to primes, according to the principle of the Sieve of Eratosthenes (that is a mathematical method of extracting prime numbers from composite numbers and thus eliminating nonprimes).12 In previous of his works such as Clepsidra I (1968–69), Clepsidra II (1970), Sita lui Eratostene (1969), or Symphony No. 2 (1973), he used the Sieve of Eratosthenes principle to control the appearance of certain musical events.13 "Time passing" and its poetical perception is the core of interest for Anatol Vieru in the Fifth Symphony. "Eternity is the ephemeral raised to continuum power"14 wrote Vieru in his...

Experimental Demonstration of a Novel Microwave Photonics Ring Modulator With Reduced Driving Power

We propose and experimentally characterise a novel microwave (MW) ring modulator design that resonantly enhances the electro-optic modulation of MW signals with center frequencies matching an integer multiple of the ring's FSR. We show that the best performance is achieved by placing the MW phase modulator in the ring's coupling section that consists of a Mach-Zehnder structure with asymmetric splitters. We fabricate the device in the SMART Photonics InP multiproject wafer run, and experimentally demonstrate that at MW frequencies corresponding to one and two times the ring's FSR, 9.5 GHz and 19 GHz respectively, our modulator enhances the generated MW output power up to 12.6 dB as compared to the equivalent Mach-Zehnder modulator, over a bandwidth of 3.8 GHz. The experiments further show that this bandwidth can be tuned to a larger value at the expense of a lower enhancement factor and this by changing one of the bias voltages. Tuning this voltage also allows to optimise the linearity of the modulator, thus demonstrating the reconfigurability of the device. Finally, we show that the novel design is not foundry-specific and detail how it can be employed to improve the performance of modulators that are fabricated by other foundries than SMART Photonics. Our design thus paves the way for the realization of devices that operate at low driving powers and can be manufactured in relatively mature fabrication processes, which are two of the key requirements for many applications such as the upcoming microwave and millimeter bands of 5G networks.

Re-study on tensegrity footbridges based on ring modules

A new class of tensegrity footbridges based on ring modules has been proposed and studied in the recent years. This article restudies the tensegrity footbridge and puts emphasis on some issues that are questionable or need further clarification in the previous studies. New cross-sectional sizes that satisfy the given internal space requirement are used for the tensegrity ring modules. The integral feasible prestresses of the tensegrity ring modules are determined and a new classification on the groups of members is proposed. A parametric study on the effects of cross-sectional areas of members and the level of prestress on the behavior of the tensegrity footbridge is carried out. The dominated parameters on the behavior of the tensegrity footbridge are identified. An improved structural efficiency index is proposed to evaluate the efficiency of the tensegrity footbridge. The effect of the number of modules on the structural efficiency index of the system is investigated. The reliability of the new index is verified through a comparison with the index proposed by a previous study. This article provides a more comprehensive understanding on the tensegrity footbridges based on ring modules.

Linear Multistep Discretization Methods With Variable Step-Size in Nonlinear Wave Digital Structures for Virtual Analog Modeling

There is a growing interest in Virtual Analog modeling algorithms for musical audio processing designed in the Wave Digital WD domain. Such algorithms typically employ a discretization strategy based on the trapezoidal rule with fixed sampling step, though this is not the only option. In fact, alternative discretization strategies possibly with an adaptive sampling step can be quite advantageous, particularly when dealing with nonlinear systems characterized by stiff equations. In this paper, we propose a unified approach for modeling capacitors and inductors in the WD domain using generic linear multi-step discretization methods with variable time-step size, and provide generalized adaptation conditions. We also show that the proposed approach for implementing dynamic energy-storing elements in the WD domain is particularly suitable to be combined with a recently developed technique for efficiently solving a class of circuits with multiple one-port nonlinearities, called Scattering Iterative Method. Finally, as examples of application, we develop WD models for a Van Der Pol oscillator and a dynamic diode-based ring modulator, which use different discretization methods.

Ring‐modulator‐based RoF system with local SSB modulation and remote carrier reuse

A full-duplex radio-over-fibre (RoF) system based on an integrated silicon ring modulator is proposed and demonstrated. For the downstream link, a coherent dual-wavelength laser source is coupled to a silicon ring modulator in the central office (CO). Since only one of the optical carriers in the dual-wavelength laser source is aligned to the resonance of the ring modulator, a single sideband (SSB) modulated optical downstream signal is obtained, which is able to combat the power fading introduced by the fibre dispersion. Besides, for the upstream link, the unmodulated optical carrier in the SSB-modulated optical downstream signal is reused by using an optical filter in the remote radio head. After being modulated by the upstream data, the optical upstream signal is transmitted back to the CO. A proof-of-concept experiment is carried out. Error vector magnitudes of 21-GHz downstream and 10-GHz upstream signals are measured, which confirms that the proposed architecture is a promising low-cost solution for future high-speed wireless communication systems.