Silicon photonics promises to address the challenges for next-generation short-reach optical interconnects. Growing bandwidth demand in hyper-scale data centers and high-performance computing motivates the development of faster and more-efficient silicon photonics links. While it is challenging to raise the serial line rate, further scaling of the data rate can be realized by, for example, increasing the number of parallel fibers, increasing the number of wavelengths per fiber, and using multi-level pulse-amplitude modulation (PAM). Among these approaches, PAM has a unique advantage because it does not require extra lasers or a costly overhaul of optical fiber cablings within the existing infrastructure. Here, we demonstrate the first fully monolithically integrated silicon photonic four-level PAM (PAM-4) transmitter operating at 56 Gb/s and demonstrate error-free transmission (bit-error-rate < 10$^{-12}$) up to 50 Gb/s without forward error correction. The superior PAM-4 waveform is enabled by optimization of silicon traveling wave modulators and monolithic integration of the CMOS driver circuits. Our results show that monolithic silicon photonics technology is a promising platform for future ultrahigh data rate optical interconnects.
We present the design and anticipated performance of an optically pumped monolithic all-silicon mid-IR (MIR) Raman laser. For the proposed 3.15 um cw laser design pumped at a 2.71 um pump wavelength, we estimate a threshold pump power of < 10 mW and an estimated output laser linewidth of <50 MHz. This design may pave the road toward demonstration of the first mid-IR silicon Raman laser.
We designed, fabricated and characterized a flat multi-level diffractive lens (MDL) comprised of only silicon with diameter = 15.2mm, focal length of 19mm, and operating over the longwave infrared (LWIR) spectrum of 8um to 14um. We experimentally demonstrated field of view of 46deg, depth of focus >7mm and wavelength-averaged Strehl ratio of 0.46. All these metrics were comparable to those of a conventional refractive lens. The active device thickness is only 8um and its weight (including the silicon substrate) is less than 0.2g.
We report on the first experimental realization of a high-reflectivity cavity mirror that solely consists of a single silicon crystal. Since no material was added to the crystal, the urgent problem of 'coating thermal noise' that currently limits classical as well as quantum measurements is avoided. Our mirror is based on a surface nanostructure that creates a resonant surface waveguide. In full agreement with a rigorous model we realized a reflectivity of (99.79+/-0.01)% at a wavelength of 1.55 μm, and achieved a cavity finesse of 2784. We anticipate that our achievement will open the avenue …
We demonstrate the generation and demultiplexing of quantum correlated photons on a monolithic photonic chip composed of silicon and silica-based waveguides. Photon pairs generated in a nonlinear silicon waveguide are successfully separated into two optical channels of an arrayed-waveguide grating fabricated on a silica-based waveguide platform.
Silicon photonics enables on-chip ultra-high bandwidth optical communications networks which is critical for the future of microelectronics1,2. By encoding information on-chip using multiple wavelength channels through the process of wavelength division multiplexing (WDM), communication bandwidths in excess of 1 Tbit s-1 are possible3. Already several optical components critical to WDM networks have been demonstrated in silicon, however a fully integrated multiple wavelength source capable of driving such a network has not yet been realized. Optical amplification, a necessary component for pro…
Cavity opto-mechanics enabled radiation pressure (RP) driven oscillators shown in the past offer an all optical Radio Frequency (RF) source without the need for external electrical feedback. However these oscillators require external tapered fiber or prism coupling and non-standard fabrication processes. In this work, we present a CMOS compatible fabrication process to design high optical quality factor opto-mechanical resonators in silicon nitride. The ring resonators designed in this process demonstrate low phase noise RP driven oscillations. Using integrated grating couplers and waveguide t…
Visible and near-infrared spectrum photonic integrated circuits are quickly becoming a key technology to address the scaling challenges in quantum information and biosensing. Thus far, integrated photonic platforms in this spectral range have lacked integrated photodetectors. Here, we report the first silicon nitride-on-silicon waveguide photodetectors that are monolithically integrated in a visible light photonic platform on silicon. Owing to a leaky-wave silicon nitride-on-silicon design, the devices achieved a high external quantum efficiency of > 60% across a record wavelength span from $λ…
Integrated optical isolators have been a longstanding challenge for photonic integrated circuits (PIC). An ideal integrated optical isolator for PIC should be made by a monolithic process, have a small footprint, exhibit broadband and polarization-diverse operation, and be compatible with multiple materials platforms. Despite significant progress, the optical isolators reported so far do not meet all these requirements. In this article we present monolithically integrated broadband magneto-optical isolators on silicon and silicon nitride (SiN) platforms operating for both TE and TM modes with …
Recently developed techniques for generating precisely equidistant optical frequencies over broad wavelength ranges are revolutionizing precision physical measurement [1-3]. These frequency "combs" are produced primarily using relatively large, ultrafast laser systems. However, recent research has shown that broad-bandwidth combs can be produced using highly-nonlinear interactions in microresonator optical parametric oscillators [4-11]. Such devices not only offer the potential for developing extremely compact optical atomic clocks but are also promising for astronomical spectroscopy [12-14], …
Silicon carbide has emerged as a promising material platform for quantum photonics and nonlinear optics. These properties make the development of integrated photonic components in high-quality silicon carbide a critical aspect for the advancement of scalable on-chip networks. In this work, we numerically design, fabricate and demonstrate the performance of monolithic metalenses from SiC suitable for on-chip optical operations. We engineer two distinct lenses, with parabolic and cubic phase profiles, operating in the near infrared spectral range, which is of interest for quantum and photonic ap…
We present a silicon optical transmitter for polarization-encoded quantum key distribution (QKD). The chip was fabricated in a standard silicon photonic foundry process and integrated a pulse generator, intensity modulator, variable optical attenuator, and polarization modulator in a 1.3 mm $\times$ 3 mm die area. The devices in the photonic circuit meet the requirements for QKD. The transmitter was used in a proof-of-concept demonstration of the BB84 QKD protocol over a 5 km long fiber link.
Silicon photonic integration has gained great success in many application fields owing to the excellent optical device properties and complementary metal-oxide semiconductor (CMOS) compatibility. Realizing monolithic integration of III-V lasers and silicon photonic components on single silicon wafer is recognized as a long-standing obstacle for ultra-dense photonic integration, which can provide considerable economical, energy efficient and foundry-scalable on-chip light sources, that has not been reported yet. Here, we demonstrate embedded InAs/GaAs quantum dot (QD) lasers directly grown on t…
We demonstrated fabrication of black silicon with slanted nanocone array on both planar and 3D micro and meso scale structures produced by a high-throughput lithography-free oblique-angle plasma etching process. Nanocones with gradual change in height were created on the same piece of silicon. The relation between the slanted angle of nanocones and incident angle of directional plasma is experimentally investigated. In order to demonstrate the monolithic integration of nanostructures on micro and meso scale non-planar surfaces, nanocone forest is fabricated on non-planar silicon surfaces in va…
High-efficiency compact optical transmitter with a total bit energy of 0.78 pJ/bit including silicon slow-light modulator and open-collector current-mode driver
We investigate the transmission of densely multiplexed solitons using a photonic integrated chip and the nonlinear Fourier-transform and analyze required launch conditions, the effect of (de-)multiplexing and noise on the nonlinear spectrum, and equalization techniques that can be used to enhance the transmission performance.
Zero-index materials exhibit exotic optical properties that can be utilized for integrated-optics applications. However, practical implementation requires compatibility with complementary metallic-oxide-semiconductor (CMOS) technologies. We demonstrate a CMOS-compatible zero-index metamaterial consisting of a square array of air holes in a 220-nm-thick silicon-on-insulator (SOI) wafer. This design is achieved through a Dirac-cone dispersion. The metamaterial is entirely composed of silicon and offers compatibility through low-aspect-ratio structures that can be simply fabricated in a standard …
Electrically-pumped lasers directly grown on silicon are key devices interfacing silicon microelectronics and photonics. We report here, for the first time, an electrically-pumped, room-temperature, continuous-wave (CW) and single-mode distributed feedback (DFB) laser array fabricated in InAs/GaAs quantum-dot (QD) gain material epitaxially grown on silicon. CW threshold currents as low as 12 mA and single-mode side mode suppression ratios (SMSRs) as high as 50 dB have been achieved from individual devices in the array. The laser array, compatible with state-of-the-art coarse wavelength divisio…
Chip-scale integrated light sources are a crucial component in a broad range of photonics applications. III-V semiconductor nanowire emitters have gained attention as a fascinating approach due to their superior material properties, extremely compact size, and the capability to grow directly on lattice-mismatched silicon substrates. Although there have been remarkable advances in nanowire-based emitters, their practical applications are still in the early stages due to the difficulties in integrating nanowire emitters with photonic integrated circuits (PICs). Here, we demonstrate for the first…
Integration of optical interconnects with silicon-based electronics can address the growing limitations facing chip-scale data transport as microprocessors become progressively faster. However, material lattice mismatch and incompatible growth temperatures have fundamentally limited monolithic integration of lasers onto silicon substrates until now. Here, we use a novel growth scheme to overcome this roadblock and directly grow on-chip InGaAs nanopillar lasers, demonstrating the potency of bottom-up nano-optoelectronic integration. Unique helically-propagating cavity modes are employed to stro…
To develop a new generation of high-speed photonic modulators on silicon-technology-based photonics, new materials with large Pockels coefficients have been transferred to silicon substrates. Previous approaches focus on realizing stand-alone devices on dedicated silicon substrates, incompatible with the fabrication process in silicon foundries. In this work, we demonstrate monolithic integration of electro-optic modulators based on the Pockels effect in barium titanate (BTO) thin films into the back-end-of-line of a photonic integrated circuit (PIC) platform. Molecular wafer bonding allows fu…
We report on polarization combining 2D grating couplers (2D GCs) on amorphous Si:H, fabricated in the backend of line of a photonic BiCMOS platform. The 2D GCs can be used as an interface of a hybrid silicon photonic coherent transmitter, which can be implemented on bulk Si wafers. The fabricated 2D GCs operate in the telecom C-band and show an experimental coupling efficiency of -5 dB with a wafer variation of +/-1.2 dB. Possibilities for efficiency enhancement and improved performance stability in future design generations are outlined and extension towards O-band devices is investigated as …
Integrated photonic circuits are one of the most promising platforms for large-scale photonic quantum information systems due to their small physical size and stable interferometers with near-perfect lateral-mode overlaps. Since many quantum information protocols are based on qubits defined by the polarization of photons, we must develop integrated building blocks to generate, manipulate, and measure the polarization-encoded quantum state on a chip. The generation unit is particularly important. Here we show the first integrated polarization-entangled photon pair source on a chip. We have impl…
We present a monolithic silicon acousto-optic frequency modulator (AOFM) operating at 1.09GHz. Direct spectroscopy of the modulated laser power shows asymmetric sidebands which indicate coincident amplitude modulation and frequency modulation. Employing mechanical levers to enhance displacement of the optical resonator resulted in greater than 67X improvement in the opto-mechanical frequency modulation factor over earlier reported numbers for silicon nanobeams.
We report on the realization and optical characterization of a CMOS-compatible silicon-based microresonator/waveguide coupled system, fully integrated on a silicon chip. The device uses a vertical coupling scheme between the resonator and a buried strip waveguide. We demonstrate that its high optical quality follows from the accurate planarization of the waveguide topography. More importantly, we demonstrate a wafer-scale mass fabrication of freestanding planar resonators suspended in air and coupled to the integrated bus waveguides. A nanometer control of the coupling distances allows for a p…
We report temporal and spectral domain observation of regenerative oscillation in monolithic silicon heterostructured photonic crystals cavities with high quality factor to mode volume ratios (Q/V). The results are interpreted by nonlinear coupled mode theory (CMT) tracking the dynamics of photon, free carrier population and temperature variations. We experimentally demonstrate effective tuning of the radio frequency (RF) tones by laser-cavity detuning and laser power levels, confirmed by the CMT simulations with sensitive input parameters.
The exponential growth of computing needs for artificial intelligence and machine learning has had a dramatic impact on data centre energy consumption, which has risen to environmentally significant levels. Using light to send information between compute nodes can dramatically decrease this energy consumption while simultaneously increasing bandwidth. Through wavelength-division multiplexing with chip-based microresonator Kerr frequency combs, independent information channels can be encoded onto many distinct colours of light in the same optical fibre for massively parallel data transmission w…
We report an optical link on silicon using micrometer-scale ring-resonator enhanced silicon modulators and waveguide-integrated germanium photodetectors. We show 3 Gbps operation of the link with 0.5 V modulator voltage swing and 1.0 V detector bias. The total energy consumption for such a link is estimated to be ~120 fJ/bit. Such compact and low power monolithic link is an essential step towards large-scale on-chip optical interconnects for future microprocessors.
We report here a monolithic photonic integration of light emitting diode (LED) with waveguide and photodetector to build a highly-integrated photonic system to perform functionalities on the GaN-on-silicon platform. Suspended p-n junction InGaN/GaN multiple quantum wells (MQWs) are used for device fabrication. Part of the LED emission is coupled into suspended waveguide and then, the guided light laterally propagates along the waveguide and is finally sensed by the photodetector. Planar optical communication experimentally demonstrates that the proof-of-concept monolithic photonic integration …
Recently, we studied the effect of hexagonal sinusoidal textures on the reflective properties of perovskite-silicon tandem solar cells using the finite element method (FEM). We saw that such nanotextures, applied to the perovskite top cell, can strongly increase the current density utilization from 91% for the optimized planar reference to 98% for the best nanotextured device (period 500 nm and peak-to-valley height 500~nm), where 100% refers to the Tiedje-Yablonovitch limit. In this manuscript we elaborate on some numerical details of that work: we validate an assumption based on the Tiedje-Y…
Wafer-scale monolithic integration of Ce:YIG films and magneto-optical isolators on silicon
National Engineering Research Centre of Electromagnetic Radiation Control Materials, University of Electronic Science and Technology of China（电磁辐射控制材料国家工程研究中心，电子科技大学）；Key Laboratory of Multi-spectral Absorbing Materials and Structures of Ministry of Education, University of Electronic Science and Technology of China（多光谱吸收材料与结构教育部重点实验室，电子科技大学）；Institute of Optics and Electronics, Chinese Academy of Sciences（中国科学院光电技术研究所）；HK Institute of Quantum Science and Technology, University of Hong Kong（香港量子科学研究所，香港大学）
The emerging applications of silicon photonics in free space, such as LiDARs and quantum photonics, urge versatile emission shaping beyond the capabilities of conventional grating couplers. A platform that offers arbitrary shaping of free-space emission while maintaining the CMOS compatibility and monolithic integration is in pressing need. Here we demonstrate a platform that integrates metasurfaces monolithically on silicon photonic integrated circuits. The metasurfaces consist of amorphous silicon nanopillars evanescently coupled to silicon waveguides. We demonstrate experimentally diffracti…
Crystalline silicon is currently being discussed as test-mass material for future generations of gravitational wave detectors that will operate at cryogenic temperatures. We present optical absorption measurements on a large-dimension sample of crystalline silicon at a wavelength of 1550nm at room temperature. The absorption was measured in a monolithic cavity setup using the photo-thermal self-phase modulation technique. The result for the absorption coefficient of this float-zone sample with a specific resistivity of 11kOhm cm was measured to be α_A=(264 +/- 39)ppm/cm.
Centre de Nanosciences et de Nanotechnologies, Université Paris-Saclay, CNRS（巴黎萨克雷大学国家科学研究中心纳米科学和纳米技术研究中心）；Université Côte d’Azur, CNRS, Institut de Physique de Nice (INPHYNI)（蔚蓝海岸大学法国国家科学研究中心尼斯物理研究所）；CEA-LETI-Minatec（法国原子能和替代能源委员会技术、电子与信息技术实验室）
Brillouin laser oscillators offer powerful and flexible dynamics as the basis for mode-locked lasers, microwave oscillators, and optical gyroscopes in a variety of optical systems. However, Brillouin interactions are exceedingly weak in conventional silicon photonic waveguides, stifling progress towards silicon-based Brillouin lasers. The recent advent of hybrid photonic-phononic waveguides has revealed Brillouin interactions to be one of the strongest and most tailorable nonlinearities in silicon. Here, we harness these engineered nonlinearities to demonstrate Brillouin lasing in silicon. Mor…
Optoelectronic signal processing offers great potential for generation and detection of ultra-broadband waveforms in the THz range, so-called T-waves. However, fabrication of the underlying high-speed photodiodes and photoconductors still relies on complex processes using dedicated III-V semiconductor substrates. This severely limits the application potential of current T-wave transmitters and receivers, in particular when it comes to highly integrated systems that combine photonic signal processing with optoelectronic conversion to THz frequencies. In this paper, we demonstrate that these lim…
Optomechanical systems offer one of the most sensitive methods for detecting mechanical motion using shifts in the optical resonance frequency of the optomechanical resonator . Presently, these systems are used for measuring mechanical thermal noise displacement or mechanical motion actuated by optical forces. Electrostatic capacitive actuation and detection have been shown previously for silicon micro electro mechanical resonators for application in filters and oscillators. Here, we demonstrate monolithic integration of electrostatic capacitive actuation with optical sensing using silicon opt…
We demonstrate the dynamics of stimulated Raman scattering in designed high-Q/Vm silicon photonic band gap nanocavities through the coupled-mode theory framework towards optically-pumped silicon lasing. The interplay of other chi(3) effects such as two-photon absorption and optical Kerr, related free-carrier dynamics, thermal effects, as well as linear losses such as cavity radiation and linear material absorption are included and investigated numerically. Our results clarify the relative contributions and evolution of the mechanisms, and demonstrate the lasing and shutdown thresholds. Our stu…
Optical isolators are an important building block in photonic computation and communication. In traditional optics, isolators are realized with magneto-optical garnets. However, it remains challenging to incorporate such materials on an integrated platform because of the difficulty in material growth and bulky device footprint. Here, we propose an ultracompact integrated isolator by exploiting graphene's magneto-optical property on a silicon-on-insulator platform. The photonic nonreciprocity is achieved because the cyclotrons in graphene experiencing different optical spin exhibit different re…
Monolithically combining silicon nitride (SiNx) photonics technology with III-V active devices could open a broad range of on-chip applications spanning a wide wavelength range of ~400-4000 nm. With the development of nitride, arsenide, and antimonide lasers based on quantum well (QW) and quantum dot (QD) active regions, the wavelength palette of integrated III-V lasers on Si currently spans from 400 nm to 11 μm with a crucial gap in the red-wavelength regime of 630-750 nm. Here, we demonstrate the first red InGaP QW and far-red InP QD lasers monolithically grown on CMOS compatible Si (001) su…
Color-center defects in silicon carbide promise opto-electronic quantum applications in several fields, such as computing, sensing and communication. In order to scale down and combine these functionalities with the existing silicon device platforms, it is crucial to consider SiC integrated optics. In recent years many examples of SiC photonic platforms have been shown, like photonic crystal cavities, film-on-insulator waveguides and micro-ring resonators. However, all these examples rely on separating thin films of SiC from substrate wafers. This introduces significant surface roughness, stra…
