A low-power integrated magneto-optic modulator on silicon for cryogenic applications
Paolo Pintus, Leonardo Ranzani, Sergio Pinna, Duanni Huang, Martin V. Gustafsson, Fotini Karinou, Giovanni Andrea Casula, Yuya Shoji, Yota Takamura, Tetsuya Miz… 展开作者
Paolo Pintus, Leonardo Ranzani, Sergio Pinna, Duanni Huang, Martin V. Gustafsson, Fotini Karinou, Giovanni Andrea Casula, Yuya Shoji, Yota Takamura, Tetsuya Mizumoto, Mohammad Soltani, John E. Bowers
A fundamental challenge of the quantum revolution is to efficiently interface the quantum computing systems operating at cryogenic temperatures with room temperature electronics and media for high data-rate communication. Current approaches to control and readout of such cryogenic computing systems use electrical cables, which prevent scalability due to their large size, heat conduction, and limited bandwidth1. A more viable approach is to use optical fibers which allow high-capacity transmission and thermal isolation. A key component in implementing photonic datalinks is a cryogenic optical modulator for converting data from the electrical to the optical domain at high speed and with low power consumption, while operating at temperatures of 4 K or lower. Cryogenic modulators based on the electro-optic effect have been demonstrated in a variety of material platforms, however they are voltage driven components while superconducting circuits are current based, resulting in a large impedance mismatch. Here, we present the first demonstration of an integrated current-driven modulator based on the magneto-optic effect operating over a wide temperature range that extends down to less than 4 K. The modulator works at data rates up to 2 Gbps with energy consumption below 4 pJ/bit, and we show that this figure can be reduced to less than 40 fJ/bit with optimized design and fabrication. This modulator is a hybrid device, where a current-driven magneto-optically active crystal (cerium substituted yttrium iron garnet, or Ce:YIG) is bonded to a high-quality silicon microring resonator. Because of its potential for extremely low power consumption under cryogenic conditions, the class of magneto-optical modulators demonstrated here has the potential to enable efficient data links in large-scale systems for quantum information processing.
Photonic integrated circuits (PICs) at cryogenic temperatures enable a wide range of applications in scalable classical and quantum systems for computing and sensing. A promising application of cryogenic PICs is to provide optical interconnects by up-converting signals from electrical to optical domain, allowing massive data-transfer from 4 K superconducting (SC) electronics to room temperature environment. Such a solution is central to overcome the major bottleneck in the scalability of cryogenic systems, which currently rely on bulky copper cables that suffer from limited bandwidth, large he…
High performance integrated electro-optic modulators operating at low temperature are critical for optical interconnects in cryogenic applications. Existing integrated modulators, however, suffer from reduced modulation efficiency or bandwidth at low temperatures because they rely on tuning mechanisms that degrade with decreasing temperature. Graphene modulators are a promising alternative, since graphene's intrinsic carrier mobility increases at low temperature. Here we demonstrate an integrated graphene-based electro-optic modulator whose 14.7 GHz bandwidth at 4.9 K exceeds the room-temperat…
Reliable operation of photonic integrated circuits at cryogenic temperatures would enable new capabilities for emerging computing platforms, such as quantum technologies and low-power cryogenic computing. The silicon-on-insulator platform is a highly promising approach to developing large-scale photonic integrated circuits due to its exceptional manufacturability, CMOS compatibility and high component density. Fast, efficient and low-loss modulation at cryogenic temperatures in silicon, however, remains an outstanding challenge, particularly without the addition of exotic nonlinear optical mat…
Integrated electrical and photonic circuits (PIC) operating at cryogenic temperatures are fundamental building blocks required to achieve scalable quantum computing, and cryogenic computing technologies. Optical interconnects offer better performance and thermal insulation than electrical wires and are imperative for true quantum communication. Silicon PICs have matured for room temperature applications but their cryogenic performance is limited by the absence of efficient low temperature electro-optic (EO) modulation. While detectors and lasers perform better at low temperature, cryogenic opt…
Lithium niobate is a promising platform for integrated quantum optics. In this platform we aim to efficiently manipulate and detect quantum states by combining superconducting single photon detectors and modulators. The cryogenic operation of a superconducting single photon detector dictates the optimisation of the electro-optic modulators under the same operating conditions. To that end, we characterise a phase modulator, directional coupler, and polarisation converter at both ambient and cryogenic temperatures. The operation voltage $V_{π/2}$ of these modulators increases due to the decrease…
Faraday and Kerr rotations are magnetooptical (MO) effects used for rotating the polarization of light in transmission and reflection from a magnetized medium, respectively. MO effects combined with intrinsically fast magnetization reversal, which can go down to a few tens of femtoseconds or less, can be applied in magnetooptical spatial light modulators (MOSLMs) promising for nonvolatile, ultrafast, and high-resolution spatial modulation of light. With the recent progress in low-power switching of magnetic and MO materials, MOSLMs may lead to major breakthroughs and benefit beyond state-of-th…
Scalable, high speed data transfer between cryogenic (0.1-4 K) and room temperature environments is instrumental in a broad range of fields including quantum computing, superconducting electronics, single photon imaging and space-based communications. A promising approach to overcome the limitations of conventional wire-based readout is the use of optical fiber communication. Optical fiber presents a 100-1,000x lower heat load than conventional electrical wiring, relaxing the requirements for thermal anchoring, and is also immune to electromagnetic interference, which allows routing of sensiti…
Many technologies in quantum photonics require cryogenic conditions to operate. However, the underlying platform behind active components such as switches, modulators and phase shifters must be compatible with these operating conditions. To address this, we demonstrate an electro-optic polarisation converter for 1550nm light at 0.8K in titanium in-diffused lithium niobate waveguides. To do so, we exploit the electro-optic properties of lithium niobate to convert between orthogonal polarisation modes with a fiber-to-fiber transmission >43%. We achieve a modulation depth of 23.6 +/-3.3dB and a c…
We introduce chip-integrated visible light communication-band modulators based on niobium (Nb) metallic plasmonic nano-antenna arrays. Our plasmonic nano-devices provide strong sensitivity to the polarization of the incident visible light and the geometrical parameters of their subwavelength nanoscale building blocks. Moreover, they offer optical modulation properties with modulation depth MD = 60% at resonant wavelength lambda= 716 nm, at room temperature. By engineering the photo response of the Nb nano-device arrays, we observe a maximum extinction A(lambda)= 1- R(lambda}) = 95 % at resonan…
We propose a device for the reversible and quiet conversion of microwave photons to optical sideband photons, that can reach 100% quantum effciency. The device is based on an erbium doped crystal placed in both an optical and microwave resonator. We show that effcient conversion can be achieved so long as the product of the optical and microwave cooperativity factors can be made large. We argue achieving this regime is feasible with current technology and we discuss a possible implementation.
Non-reciprocal components are essential in photonic systems for protecting light sources and for signal routing functions. Acousto-optic methods to produce non-reciprocal devices offer a foundry-compatible alternative to magneto-optic solutions and are especially important for photonic integration. In this paper, we experimentally demonstrate a dynamically reconfigurable non-reciprocal acousto-optic modulator at telecom wavelength. The modulator can be arranged in a multitude of reciprocal and non-reciprocal configurations by means of an external RF input. The dynamic reconfigurability of the …
Light modulation is an essential operation in photonics and optoelectronics. With existing and emerging technologies increasingly demanding compact, efficient, fast and broadband optical modulators, high-performance light modulation solutions are becoming indispensable. The recent realization that two-dimensional layered materials could modulate light with superior performance has prompted intense research and significant advances, paving the way for realistic applications. In this review, we cover the state-of-the-art of optical modulators based on two-dimensional layered materials including …
We present here a small-scale liquid Helium (LHe) immersion cryostat with an innovative optical setup suitable to work in long wavelength radiation ranges and under applied magnetic field. The cryostat is a multi stage device with several shielding in addition to several optical stages. The system has been designed with an external liquid Nitrogen boiler to reduce the liquid bubbling. The optical and mechanical properties of the optical elements were calculated and optimized for the designed configuration while the optical layout has been simulated and optimized among different configurations …
Optical isolators, while commonplace in bulk- and fiber-optic systems, remain a key missing component in integrated photonic systems. Isolation using magneto-optic effects has been difficult to implement due to fabrication restraints, motivating use of other non-reciprocal effects such as temporal modulation. We demonstrate a non-reciprocal modulator comprising a pair of microring modulators and a microring phase shifter in an active silicon photonic process which, in combination with standard frequency filters, facilitates isolation. Isolation up to 13 dB is measured with a 3 dB bandwidth of …
Encoding information onto optical fields is the backbone of modern telecommunication networks. Optical fibers offer low loss transport and vast bandwidth compared to electrical cables, and are currently also replacing coaxial cables for short-range communications. Optical fibers also exhibit significantly lower thermal conductivity, making optical interconnects attractive for interfacing with superconducting circuits and devices. Yet little is known about modulation at cryogenic temperatures. Here we demonstrate a proof-of-principle experiment, showing that currently employed Ti-doped LiNbO mo…
We study magneto-optical coupling in a ferrimagnetic sphere resonator made of Yttrium iron garnet. We find that the resonator can be operated in the telecom band as a polarization-selective optical modulator. Intermodulation gain can be employed in the nonlinear regime for amplification.
We report on a giant Faraday effect in an electron plasma in n-InSb probed via polarization-resolved terahertz (THz) time-domain spectroscopy. Polarization rotation angles and ellipticities reach as large as π/2 and 1, respectively, over a wide frequency range (0.3-2.5 THz) at magnetic fields of a few Tesla. The experimental results together with theoretical simulations show its promising ability to construct broadband and tunable THz polarization optics, such as a circular polarizer, half-wave plate, and polarization modulators.
We describe a two-color pump-probe scanning magneto-optical Kerr effect (MOKE) microscope which we have developed to investigate electron spin phenomena in semiconductors at cryogenic temperatures with picosecond time and micrometer spatial resolution. The key innovation of our microscope is the usage of an ultrafast `white light' supercontinuum fiber-laser source which provides access to the whole visible and near-infrared spectral range. Our Kerr microscope allows for the independent selection of the excitation and detection energy while avoiding the necessity to synchronize the pulse trains…
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）
We study electromagnetically induced transparency (EIT) in a heated potassium vapor cell, using a simple optical setup with a single free-running diode laser and an acousto-optic modulator. Despite the fact that the Doppler width is comparable to the ground state hyperfine splitting, transparency windows with deeply sub-natural line widths and large group indices are obtained. A longitudinal magnetic field is used to split the EIT feature and induce magnetooptical anisotropy. Using the beat note between co-propagating coupling and probe beams, we perform a heterodyne measurement of the circula…
We present a magneto-optical study of the carrier dynamics in compressively strained Ge(1-x)Sn(x) films having Sn compositions up to 10% epitaxially grown on blanket Ge on Si (001) virtual substrates. We leverage the Hanle effect under steady-state excitation to study the spin-dependent optical transitions in presence of an external magnetic field. This allowed us to obtain direct access to the dynamics of the optically-induced carrier population. Our approach singled out that at cryogenic temperatures the effective lifetime of the photogenerated carriers in coherent Ge(1-x)Sn(x) occurs in the…
We develop a new approach in magneto-optical imaging (MOI), applying for the first time a ghost imaging (GI) protocol to perform Faraday microscopy. MOI is of the utmost importance for the investigation of magnetic properties of material samples, through Weiss domains shape, dimension and dynamics analysis. Nevertheless, in some extreme conditions such as e. g. cryogenic temperatures or high magnetic fields application, there exists a lack of domains images due to the difficulty in creating an efficient imaging system in such environments. Here we present an innovative MOI technique that separ…
