Silicon Photonics technology is rapidly maturing as a platform for larger‐scale photonic circuits. As a result, the associated design methodologies are also evolving from component‐oriented design to ...a more circuit‐oriented design flow, that makes ion from the very detailed geometry and enables design on a larger scale. In this paper, the state of this emerging photonic circuit design flow and its synergies with electronic design automation (EDA) are reviewed. The design flow from schematic capture, circuit simulation, layout and verification is covered. The similarities and the differences between photonic and electronic design, and the challenges and opportunities that present themselves in the new photonic design landscape, such as variability analysis, photonic‐electronic co‐simulation and compact model definition are discussed.
A review of the recent developments in integrated photonic circuit design is presented, focusing specifically on the needs for large‐scale silicon photonics circuits. The distinction between photonic device design and circuits is made, illustrating where photonic circuit design is gradually converging with electronic circuit design flows and tools. Challenges in photonic model building, photonic‐electronic cosimulation, design for manufacturability, yield prediction and verification of photonic circuits are discussed in detail.
Silicon photonics is widely acknowledged as a game-changing technology, driven by the needs of datacom and telecom. Silicon photonics builds on highly capital-intensive manufacturing infrastructure, ...and mature open-access silicon photonics platforms are translating the technology from research fabs to industrial manufacturing levels. To meet the current market demands for silicon photonics manufacturing, a variety of open-access platforms is offered by CMOS pilot lines, R&D institutes, and commercial foundries. This paper presents an overview of existing and upcoming commercial and noncommercial open-access silicon photonics technology platforms. We also discuss the diversity in these open-access platforms and their key differentiators.
We look at the opportunities presented by the new concepts of generic programmable photonic integrated circuits (PIC) to deploy photonics on a larger scale. Programmable PICs consist of waveguide ...meshes of tunable couplers and phase shifters that can be reconfigured in software to define diverse functions and arbitrary connectivity between the input and output ports. Off-the-shelf programmable PICs can dramatically shorten the development time and deployment costs of new photonic products, as they bypass the design-fabrication cycle of a custom PIC. These chips, which actually consist of an entire technology stack of photonics, electronics packaging and software, can potentially be manufactured cheaper and in larger volumes than application-specific PICs. We look into the technology requirements of these generic programmable PICs and discuss the economy of scale. Finally, we make a qualitative analysis of the possible application spaces where generic programmable PICs can play an enabling role, especially to companies who do not have an in-depth background in PIC technology.
We propose an equivalent circuit model for the coplanar waveguide (CPW) which serves as the traveling wave electrode to drive carrier-depletion-based silicon modulators. Conformal mapping and partial ...capacitance techniques are employed to calculate each element of the circuit. The validity of the model is confirmed by the comparison with both finite-element simulation and experimental result. With the model, we calculate the modulation bandwidth for different CPW dimensions and termination impedances. A 3 dB modulation bandwidth of 15 GHz is demonstrated with a traveling wave electrode of 3 mm. The calculation indicates that, by utilizing a traveling wave electrode of 2 mm, we can obtain a 3 dB modulation bandwidth of 28 GHz.
We studied a refractive index sensor that consists of two cascaded ring resonators and that works analogously to a Vernier-scale. We implemented it in silicon-on-insulator and experimentally ...determined its sensitivity to be as high as 2169 nm/RIU in aqueous environment. We derived formulas describing the sensor's operation, and introduced a fitting procedure that allows to accurately detect changes in the sensor response. We determined the detection limit of this first prototype to be 8.310(-6)RIU.
We propose a novel filter circuit that incorporates a double ring resonator with a balanced Mach-Zehnder interferometer (MZI). The circuit has a response equivalent to a conventional ring loaded MZI ...filter, but with added flexibility in terms of configurability. The second-order filter can also be cascaded to realize higher-order filters. The circuit incorporates a two-stage input and output coupler to further reduce the effect of dispersion. A combination of local and global optimization strategies to program the filter, using tailored objective functions, have been tested in simulation and experiments. To our best knowledge, this is the first time a global optimization strategy is directly used in ARMA filter synthesis and simulation without any additional requirement. We further extend the optimization strategy into experiments and demonstrated its use in practical case for programmable filter circuits.
A novel wideband parametric baseband macromodeling technique for passive photonic devices and circuits is presented. It allows to efficiently estimate the baseband scattering representations of a ...linear, passive photonic system as a function of a set of design variables, such as geometrical layout or substrate features. The proposed technique relies on the interpolation of macromodels computed via a complex vector fitting (CVF) algorithm, by adopting a methodology based on amplitude and frequency scaling that preserves, by construction, the physical properties of the system, such as causality, stability and passivity. For a specified combination of the design parameters, a rational CVF model is derived that can be simulated by a wide range of ordinary differential equation (ODE) solvers or circuit simulators. Additionally, time-domain simulations using the computed model can be performed at arbitrary optical carrier frequencies, thus allowing for the simulation of multi-wavelength systems. Two application examples are presented to demonstrate the flexibility and advantages of the proposed method.
We demonstrate compact silicon-on-insulator-based arrayed waveguide gratings (AWGs) for (de)multiplexing applications with a large free spectral range (FSR). The large FSR is obtained by reducing the ...arm aperture pitch without changing the device footprint. We demonstrate 4 × 100 GHz, 8 × 250 GHz, and 12 × 400 GHz AWGs with FSRs of 6.9, 24.8, and 69.8, respectively. We measured an insertion loss from -2.45 dB for high to -0.53 dB for low-resolution AWGs. The crosstalk varies between 17.12 and 21.37 dB. The bandwidth remains nearly constant, and the nonuniformity between the center wavelength channel and the outer wavelength channel improves with larger FSR values.
Silicon photonics has developed into a mainstream technology driven by advances in optical communications. The current generation has led to a proliferation of integrated photonic devices from ...thousands to millions-mainly in the form of communication transceivers for data centers. Products in many exciting applications, such as sensing and computing, are around the corner. What will it take to increase the proliferation of silicon photonics from millions to billions of units shipped? What will the next generation of silicon photonics look like? What are the common threads in the integration and fabrication bottlenecks that silicon photonic applications face, and which emerging technologies can solve them? This perspective article is an attempt to answer such questions. We chart the generational trends in silicon photonics technology, drawing parallels from the generational definitions of CMOS technology. We identify the crucial challenges that must be solved to make giant strides in CMOS-foundry-compatible devices, circuits, integration, and packaging. We identify challenges critical to the next generation of systems and applications-in communication, signal processing, and sensing. By identifying and summarizing such challenges and opportunities, we aim to stimulate further research on devices, circuits, and systems for the silicon photonics ecosystem.
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