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We demonstrate a silicon photonic transmitter for soliton-based communications enabling the interleaving of QPSK and APSK modulated soliton pulses overlapping in both the time and frequency domains. The nonlinear Fourier transform is used to both determine adequate soliton launch conditions and facilitate nonlinear equalization at the receiver. A s...
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... RF PCB has to support the high density of control signals, the grounded co-planar waveguide (GCPW) RF transmission lines, and has to enable short wire bonds to the PIC to minimize RF insertion losses and back-reflections at the PCB to PIC interface. These requirements are supported by the multilayer stack shown in Fig. 8. A thin substrate is used on the top side between the RF lines and the underlying ground planes to shrink the lateral dimensions of the transmission lines and enable a compact RF pad frame. Symmetric bottom layers are used for the control signal fan-out. A thick substrate core is placed in the middle to enable a sufficiently deep ...
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... can have an effect on NFCs associated to other eigenvalues. If the expected transmitted λ k are known at the Rx, e.g., if they are not themselves used for modulation, deviations can be used to equalize the received NFCs [44], [46]. Exemplarily, the correlation between deviations of the modulated b(λ k ) and the eigenvalue λ k are depicted in Fig. 18. For this plot, the transmission of 10000 first-order solitons over 60 spans of 50 km NZDSF using lumped amplification with an EDFA noise-figure of 5 dB was simulated. Additionally, if only b(λ k ) is modulated, a (λ k ) can also be fixed and used for equalization purposes. This has been shown to be advantageous for eigenvalue ...
Citations
... Silicon photonic integrated circuits (PICs) have shown tremendous potential in areas such as optical communications, optical computing and microwave photonic systems, providing a lightweight and cost-effective alternative to traditional electro-optic systems [1][2][3][4][5][6]. In the development of large-scale PICs, the 2 × 2 optical switch plays a crucial role as a key component in the construction of various on-chip optical networks. ...
We have designed and experimentally demonstrated a compact 2 × 2 silicon thermo-optic Mach-Zehnder switch with a Pπ of ∼ 1.4 mW and an extinction ratio of > 28 dB over C-band. We use spiral configurations for both the silicon waveguide and the metal heater in the phase shifters to improve thermal efficiency. The densely packed silicon waveguides are connected by hybrid Euler bends. The adjacent straight waveguides have different widths of 400 nm and 550 nm to achieve isolation between the optical fields. We present simulation results of the hybrid Euler bends and the thermal field distribution. The device is fabricated by e-beam lithography, dry etching, and e-beam evaporation, resulting in a device footprint of ∼ 0.24 × 0.36 mm², with each phase shifter occupying ∼ 0.11 × 0.11 mm². The measured Pπ of ∼ 1.4 mW is in agreement with the simulations. The extinction ratio is > 28 dB over the C-band due to the highly balanced 2 × 2 multimode interferometer (MMI) coupler used. This device is well suited for the construction of large-scale photonic integrated circuits (PICs) for applications requiring a large number of 2 × 2 optical switches with low crosstalk and low power consumption, such as optical beamforming networks (OBFNs) for microwave beamforming and optical phased arrays (OPAs) for optical beamforming.
... Photonic packaging is a critical aspect of the photonic ecosystem following on from a rapid growth of Photonic Integrated Circuit (PIC) based technologies. There exist numerous highly innovative PIC-based solutions for a wide range of applications and markets such as sensors [1,2], telecoms [3,4], bio-medical [5][6][7] and LIDAR (Light Detection and Ranging) [8]. However, as chips become more complicated, there are assembly and packaging bottlenecks that impede the commercialization of the full systems. ...
We propose a method for aligning and attaching micro-lens arrays to photonic integrated circuits (PICs). Unlike the conventional approach of assessing power coupled to a fiber directly, our method utilizes a beam profiler. This profiler allows us to optimize the lens position by analyzing the transmitted beam shape from the PIC edge coupler through the lens. In conjunction, we employ grating couplers to introduce external light, acting as a ‘beacon’ for optimization. The use of grating couplers enables efficient coupling of external light into the PIC, providing a reference point for alignment. Importantly, our method accommodates both regular waveguide-side-up and upside-down (through-Silicon) orientations of the PIC. This versatility allows us to reproduce coupling results across a 6-channel array, demonstrating robust performance. This innovative approach not only ensures precise alignment and attachment but also opens up new possibilities for photonic packaging. The flexibility to work in different orientations is likely to lead to advancements in the design and assembly of photonic devices.
... These miniaturized filters also find applications in sensitive sensing systems, where they enhance data accuracy in fields like medical diagnostics and environmental monitoring. Additionally, the development of miniaturized filters aligns with the trend towards energy-efficient systems, reducing energy consumption in optical setups (Moscoso-Mártir et al. 2022). ...
This paper reports the design and numerical results of three new extremely compact and efficient flat-top band-pass plasmonic filters operating in the near-infrared region. The proposed structures are realized in metal–insulator-metal plasmonic waveguides based on stub, tilted T-junction and right-angle trapezoid configurations. A built-in parameterized genetic algorithm is applied to maximize the transmission efficiency, while at the same time contributing to shrinking down the size of the device structures. It is shown that the tunability of the optical filters can be realized by modulating their structural parameters to gain control over the band-pass filtering wavelengths. Numerical calculations are conducted based on the finite element method of CST Microwave Studio and demonstrate that the suggested ultra-compact plasmonic waveguide filters offer wide bandwidths of more than 270 nm, 424 nm, and 289 nm, with transmission efficiencies of higher than 80%, 74.2%, and 74.3%, respectively. The sizes of the proposed wavelength filters are 490 nm × 575 nm, 350 nm × 180 nm, and 420 nm × 150 nm, respectively, which make them attractive candidates for applications in high density photonic integrated circuits (PICs). As a result, because of the promising characteristics of the proposed topologies such as their high efficiency, compact size, tunability, and simple structure they may find applications in on-chip integration, laser technology, and multi-photon fluorescence.
... Nonlinearity is a challenge for transmitting information in fiber optics communications with the commonly used modulation formats. Indeed, as the power is increased, the nonlinear crosstalk distorts the signal further, thereby limiting the recipient's ability to retrieve the transmitted information [3][4][5][6][7]. Therefore, to compensate for the distortions, it is important to minimize the nonlinear effects and to provide innovative approaches to connectivity over the nonlinear fiber-optic channel [8]. ...
... Self-phase modulation (SPM) is the nonlinearity and group velocity dispersion is the dispersion (GVD). These two counteracting effects produce solitons that the nonlinear Schrodinger equation can explain (NLSE) [4][5][6]. Solitons, when used with erbium-doped amplifiers (EDFAs), are potential candidates for high bit rate long-haul links due to their robust nature (tolerance to dispersion and nonlinearity). ...
Fiber optics telecommunication is the currently established backbone infrastructure for most of the information flow across the world. New services and applications are causing an exponential increase in Internet traffic, increasing transmission rate, and high bandwidth-demanding applications have been propelling the data rate per wavelength to approach the speed limit of electronics. In a few years, the current fiber optic communication system infrastructure will not be able to meet this demand because fiber nonlinearity dramatically limits the information transmission rate. Also, the dispersion phenomenon is a problem for high bit rates and long-haul optical communication systems. An easy solution to this problem is optical solitons pulses that preserve their shape over long distances. An optical soliton is formed by balancing nonlinearity (self-phase modulation) and dispersion phenomenon (group velocity dispersion). In this review article, a detailed study of optical solitons is presented along with its recent progress. Advanced numerical methods such as Darboux transform (DT), digital back propagation, split step Fourier, and forward–backward methods are also discussed in this paper which is used for solving higher-order solitons.
... The ability to sense air pollution and network numerous devices to measure is enabled by photonic-based technology. Siemens has created a method for monitoring carbon monoxide levels that uses a laser and is significantly more accurate than traditional sensors (Moscoso-Mártir et al. 2022). Kenneth Suslick describes the intriguing concept of an "Artificial nose" that can identify toxins (Lee et al. 2022a). ...
This book covers the advanced fabrication techniques, challenges, and applications of photonic crystals for next-generation systems in various applications such as high-speed networks, photonic integrated circuits, health care, sensors, energy, and environmental. This book highlights the literature and works put forward by various scientists, researchers, and academicians in photonic crystals and their real-time applications. The content of the book appeals to readers such as students, researchers, and industrial engineers who are working in the design and development of photonics-based concepts, components, and devices for various applications.
... 1,2 The bottleneck to achieving these is to find EO modulators that have higher bit rates per wavelength, lower power consumption, smaller device size, and longer optical reach in coherent transceivers. Several material platforms have shown distinct advantages as strong candidates for nextgeneration coherent modulators in long-haul links, such as silicon photonics, 3,4 indium phosphine, 5,6 gallium arsenide, 7 and lithium niobate (LN). 8 Among them, LN can offer a linear Pockels effect, a wide transparency window, and less wavelength independence, which makes LN modulators extra competitive in long-haul networks. ...
Coherent technology has been employed in long-haul transmission systems in the past decade, with growing demand for capacity at ever-lower costs per bit. High-performance coherent modulators with high data rates, wide bandwidth, small footprint, and low power operation are highly desired. Toward this end, we propose a folded thin-film lithium niobate (TFLN) dual-polarization in-phase quadrature modulator featuring a low half-wave voltage of 1 V and a compact footprint of 4 × 8 mm2. To suppress RF wavefront distortion and optimize high-frequency electro-optic performance, we utilize air-bridge structures in the U-turns of the traveling-wave electrodes. As a demonstration of the long-haul transmission capacities with our device, we present driverless 703 Gb/s/λ line-rate transmissions, with a subcarrier modulation scheme, over a 1120 km single-mode fiber link. Here, for the first time, to our knowledge, our device allows for attojoule-per-bit level electrical energy consumption over transmission distances above 1000 km. The device opens opportunities for much lower-cost and capacity-intensive coherent systems that consume ultra-low power, support high data rate, and work in small spaces.
... Digital electronic ANNs have already been successfully applied to such nonlinear equalization tasks in both short reach fiber links 51 and long haul communications. 52 In this study, we apply nonlinear equalization to the output of the optically enabled (OE), time-interleaved (TI-)ADC architecture shown in Fig. 9(b), for which we have previously benchmarked linear feed-forward equalization (FFE) with digital electronics. 53 The OE-TI-ADC samples an electrical signal by applying it to a Mach-Zehnder modulator (MZM), to which pulses with different center wavelengths are being fed. ...
We propose a new signaling scheme for on-chip optical-electrical-optical artificial neural networks that utilizes orthogonal delay division multiplexing and pilot-tone based self-homodyne detection. This scheme offers a more efficient scaling of the optical power budget with increasing network complexity. Our simulations, based on a 220 nm SOI silicon photonics technology, suggest that the network can support 31 x 31 neurons, with 961 links and freely programmable weights, using a single 500 mW optical comb and an SNR of 21.3 dB per neuron. Moreover, it features a low sensitivity to temperature fluctuations, ensuring that it can be operated outside of a laboratory environment. We demonstrate the network's effectiveness in nonlinear equalization tasks by training it to equalize a time-interleaved ADC architecture, achieving an ENOB over 4 over the entire 75 GHz ADC bandwidth. We anticipate that this network architecture will enable broadband and low latency nonlinear signal processing in practical settings such as ultra-broadband data converters and real-time control systems.
... However, the cascaded solution presented in [7] scales poorly with the number of channels due to the ~6 dB losses introduced there in each stage. To enable scalability, we introduce the photonic integrated circuit (PIC) architecture shown in Fig. 2, which is an extension of our PIC that has been successfully used to launch densely packed solitons [8]. In the proposed Tx architecture, the comb laser lines are first demultiplexed using coupled (ring-)resonator optical waveguide (CROW) filters and used as carriers to generate individual channels. ...
... A small 1-GHz overlap already reduces the BER enough to achieve error-free transmission when using the 7% overhead hard decision forward error correction (HD-FEC) limit of 3.7 × 10 −3 for 16-QAM or a 20% overhead soft decision (SD-)FEC limit of 2 × 10 −2 for 32-QAM. This performance can be further improved by using neural network equalizers [3], dual polarization (double SE), probabilistic shaping [10], or joint modulation with the discrete part of the spectrum [8]. ...
We present a highly scalable PIC-based nonlinear frequency division multiplexed transmission system in which b-modulated channels are wavelength division multiplexed with spectral overlap so as to obtain a seamless spectrum without frequency guard bands.
... Exploring the role of geometrical symmetry and topology on the electronic and optical responses of solid state systems is an ever-interesting field of physics. Particularly being able to tailor the dispersion of the optical and matter waves via a periodic potential landscape, for example in lattices of atoms or nanostructures, allows for fabulous applications in either integrated photonics [1][2][3][4] or electronics systems [5,6], and provisionally the photonic-electronic interconnects [7][8][9]. In addition, manipulating the spin, the phase, or the angular momentum of the optical or electronic wave functions provide control knobs for further engineering the energy and the propagation directions of the waves via interactions between the linear and angular momenta [10,11]. ...
Degeneracy is an omnipresent phenomenon in various physical systems, which has its roots in the preservation of geometrical symmetry. In electronic and photonic crystal systems, very often this degeneracy can be broken by virtue of strong interactions between photonic modes of the same energy, where the level repulsion and the hybridization between modes causes the emergence of photonic bandgaps. However, most often this phenomenon does not lead to a complete and inverted bandgap formation over the entire Brillouin zone. Here, by systematically breaking the symmetry of a two-dimensional square photonic crystal, we investigate the formation of Dirac points, line node singularities, and inverted bandgaps. The formation of this complete bandgap is due to the level repulsion between degenerate modes along the line nodes of a semimetal-like photonic crystal, over the entire Brillouin zone. Our numerical experiments are performed by a home-build numerical framework based on a multigrid finite element method. The developed numerical toolbox and our observations pave the way towards designing complete bandgap photonic crystals and exploring the role of symmetry on the optical behaviour of even more complicated orders in photonic crystal systems.
Nonlinear frequency division multiplexing (NFDM) offers a possible solution to the fiber nonlinearity-induced signal distortion in the optical fiber networks. However, the application of NFDM is challenged during the information retrieval after perturbed propagation. The paper proposes a novel, to the best of our knowledge, nonlinear frequency domain neural network (NN)-based equalizer that exploits the phase relationship between modulated information on different eigenvalues. Similar parameters are utilized in a time-domain NN to address the overall complexity issue of the receiver. Such configurations enhance performance and reduce the computational complexity. In the dual-polarization NFDM (DP-NFDM) transmitting systems, the proposed NN-based equalizers successfully maintain a low bit error rate (BER) after up to 2800 km transmission, demonstrating an effective approach to address the perturbation issue in NFDM.
