Custom Chips Research Papers
Few-cycle vacuum squeezing in nanophotonics
Authors: Rajveer Nehra, Ryoto Sekine, Luis Ledezma, Qiushi Guo, Robert M. Gray, Arkadev Roy, and Alireza Marandi
Publisher: Science
Executive Summary
Squeezed states of light are one of the fundamental resources of quantum information science, enabling applications such as quantum computing, secure communications, precision sensing, and quantum-enhanced metrology. Although these quantum states have traditionally been generated using large laboratory optical systems, creating and measuring high-quality squeezed light on an integrated photonic chip has remained a major challenge. Existing approaches often suffer from limited bandwidth, significant optical losses, and measurement techniques that restrict scalability.
This research demonstrates a fully integrated lithium niobate nanophotonic platform capable of both generating and measuring squeezed quantum states on the same chip. By combining two dispersion-engineered optical parametric amplifiers (OPAs), the device first generates a squeezed vacuum state and then performs an all-optical measurement through high-gain, phase-sensitive amplification. This approach eliminates many of the limitations associated with conventional photodetection, allowing quantum states to be measured with significantly greater tolerance to optical losses while preserving their quantum properties.
The platform achieved up to 4.9 dB of directly measured squeezing across more than 25 terahertz of optical bandwidth, supporting ultrashort quantum states lasting only a few optical cycles. After accounting for system losses, the inferred squeezing exceeds 10 dB—a performance level considered sufficient for many fault-tolerant continuous-variable quantum computing architectures. Achieving this level of performance on a compact integrated chip represents an important milestone toward practical, scalable quantum photonic systems.
Beyond demonstrating high-quality squeezed light, the research introduces a new method for all-optical quantum measurement that overcomes one of the longstanding bottlenecks in integrated quantum photonics. Traditional balanced homodyne detection is highly sensitive to optical losses and limited in bandwidth, whereas the demonstrated phase-sensitive amplification technique enables broadband, loss-tolerant measurements that can fully leverage the ultrafast nature of integrated photonic devices.
By combining broadband quantum light generation, integrated measurement, and the scalability of thin-film lithium niobate, this work establishes a practical foundation for next-generation quantum photonic processors. The demonstrated architecture enables compact, wafer-scale quantum systems capable of supporting continuous-variable quantum computing, quantum communications, precision sensing, and ultrafast quantum information processing. As integrated quantum technologies continue to mature, this research represents a significant step toward scalable, high-performance quantum photonic platforms that can move beyond laboratory demonstrations into real-world applications.
Femtojoule femtosecond all-optical switching in lithium niobate nanophotonics
Authors: Qiushi Guo, Ryoto Sekine, Luis Ledezma, Rajveer Nehra, Devin J. Dean, Arkadev Roy, Robert M. Gray, Saman Jahani & Alireza Marandi
Publisher: Nature Photonics
Executive Summary
All-optical switching is a fundamental capability for the future of photonic computing, communications, and signal processing, enabling information to be processed entirely with light rather than through slower and more energy-intensive electronic components. However, realizing practical all-optical switches on integrated photonic chips has remained a significant challenge. Most existing platforms rely on inherently weak optical nonlinearities, requiring large amounts of energy, resonant cavities, or complex material integration that limit performance, scalability, and speed.
This research demonstrates a breakthrough in integrated photonics by achieving cavity-free all-optical switching using thin-film lithium niobate nanowaveguides. By combining dispersion engineering with quasi-phase matching, the researchers harnessed the material's strong second-order nonlinear optical response to create an ultrafast nonlinear optical splitter capable of switching light with exceptionally low energy and without the need for resonant structures. This architecture simplifies device design while overcoming many of the limitations that have constrained previous integrated optical switching technologies.
The demonstrated device achieves switching energies as low as 80 femtojoules with an ultrafast switching time of approximately 46 femtoseconds, representing one of the fastest and most energy-efficient all-optical switching demonstrations reported in integrated photonics. Together, these results produce a record-low energy-time product, highlighting the platform's ability to perform optical switching at unprecedented speed while minimizing power consumption.
Unlike conventional approaches that require optical cavities to enhance weak nonlinear interactions, this cavity-free design supports broadband operation, avoids resonance-related constraints, and provides a more scalable foundation for large photonic circuits. The use of thin-film lithium niobate further enables compatibility with advanced integrated photonic manufacturing while leveraging one of the strongest nonlinear materials available for chip-scale devices.
By combining ultrafast response, exceptional energy efficiency, and compact integrated implementation, this work establishes a new benchmark for nonlinear optical switching in nanophotonics. The demonstrated technology provides a practical foundation for next-generation all-optical systems that can process information at the speed of light while dramatically reducing latency and energy consumption.
This breakthrough opens new opportunities for optical computing, photonic neural networks, high-speed communications, ultrafast signal processing, and integrated light sources. As demand for faster and more energy-efficient computing infrastructure continues to grow, cavity-free all-optical switching represents a critical building block for future photonic processors and scalable optical information processing systems.