International Defense Security & Technology Your trusted Source for News, Research and Analysis
Related Articles
Low-noise optical detectors are vital components in sensing and communication. While boosting the strength of a signal to the required signal to noise ratio (SNR) for a given optical system often entails trade-offs with size, weight, and power consumption, lowering noise directly translates to greater capabilities across optical science and technology. However, the particle nature of light results in a fundamental quantum noise limit that bounds the performance of laser-based optical systems. The Intensity-Squeezed Photonic Integration for Revolutionary Detectors (INSPIRED) program seeks to break this limit using quantum integrated photonics.
INSPIRED is leveraging a quantum state of light known as “squeezed light”. Sophisticated experiments over the past fifteen years have demonstrated that employing squeezed light in the measurement of weak signals can exceed the quantum noise limit. Tabletop squeezed light systems have been used for demonstrations of quantum-enhanced optical sensing – most famously by the gravitational-wave astronomy community to detect cosmic events such as black hole and neutron star mergers from further in space.
The same time period has also witnessed a revolution in integrated photonics: the manipulation of light with microscopic devices on chips. With recent progress in nonlinear integrated photonics, large-scale photonic circuits, and photonic heterogeneous integration, chip-scale optical devices are beginning to outperform bulk, discrete optical components.
The INSPIRED program is pursuing these advances to implement squeezed-light measurement techniques in form factors comparable to commercial photodetector modules.
Such “squeezed-light detectors” will be transformative in advancing ultra-sensitive measurements beyond laboratory environments as practical, general-purpose components that can enhance the performance of diverse optical systems for imaging, navigation, signal processing, microscopy, communications, and quantum computing.
The INSPIRED Program: Shattering Quantum Limits
In a bold move to transcend the quantum noise floor, DARPA launched the INSPIRED program—Intensity-Squeezed Photonic Integration for Revolutionary Detectors—awarding a $9.3 million contract in December 2024 to RTX BBN Technologies. The program’s core objective is to overcome the quantum shot noise limit, a phenomenon caused by random fluctuations in photon detection that undermines sensitivity in low-light environments. Whether it’s fog, deep space, or tactical imaging under cover of night, traditional electro-optical sensors fail when light levels drop. INSPIRED aims to flip this script by leveraging a property of quantum mechanics known as squeezed light, which reduces uncertainty in one measurement (like intensity) at the expense of another (like phase), thereby enhancing signal detection beyond conventional limits.
This project isn’t simply about tinkering with sensitivity. INSPIRED seeks a leap in capability through a convergence of technologies. At its core is nonlinear integrated photonics, which confines light into extremely small structures, amplifying the squeezing effect without requiring bulky optical setups. The goal is to surpass the current state-of-the-art squeezing levels of 10 decibels and push beyond 16 decibels—translating into the ability to detect signals up to 40 times fainter than what’s currently possible.
To make this leap, INSPIRED is bringing together multiple breakthroughs in one integrated architecture. RTX BBN is working in close coordination with the University of Maryland, which is developing superconducting nanowire detectors; Raytheon Advanced Technology, which is contributing RF synthesizers; and Xanadu Quantum, known for its work in quantum photonics. The two-phase development roadmap begins with developing a chip-scale squeezed-light generator and a low-loss optical interferometer, aiming for greater than 12 dB squeezing and less than 3% optical loss. Phase two, stretching into 2027, will integrate all components into a compact prototype with a total volume under 500 cm³ and a target sensitivity 16 dB below the quantum noise threshold.
Why Squeezed Light? The Military Imperative
The battlefield of the future demands more than just better sensors—it requires an entirely new paradigm of sensing. From drones operating in contested airspace to soldiers needing tactical awareness in degraded environments, the limitations of conventional electro-optical systems have become more pronounced. These systems are hampered by three critical challenges: physical size and power requirements, environmental obscuration from dust or fog, and the intrinsic noise floor dictated by quantum mechanics.
Squeezed light directly addresses these constraints. By manipulating the quantum properties of photons, sensors can now extract more information from fewer particles of light, essentially seeing in the dark. For the military, this means drones can be made smaller and stealthier, sensors can function through battlefield haze or nighttime conditions, and signal acquisition can be achieved at longer distances with more clarity.
The applications of these advances are far-reaching. Hyperspectral imaging systems, for instance, could benefit from squeezed-light sensors to detect material compositions invisible to traditional optics—such as spotting real tanks hidden among decoys by analyzing their unique spectral signatures. Quantum sensors could also enhance magnetic anomaly detection, enabling the identification of submarines or buried explosives through subtle variations in the Earth’s magnetic field. Additionally, the same principles could strengthen secure communications, using quantum-encrypted channels immune to interception and eavesdropping, ensuring secure links in forward-deployed operations.
RTX BBN: The Quantum Vanguard
Leading the INSPIRED initiative is RTX BBN Technologies, a trailblazer with a legacy rooted in the creation of the ARPANET and more recently in quantum encryption technologies. BBN’s approach to INSPIRED is a strategic triad that leverages cutting-edge innovations in quantum optics and integrated systems.
The first pillar of their strategy lies in Photonic Integrated Circuits (PICs). These circuits condense what used to be entire optical laboratories onto silicon chips, creating scalable, rugged, and cost-effective platforms for quantum sensing. Using microring resonators and waveguides, PICs generate squeezed light in compact, thermally stable formats.
The second innovation comes from AI-enhanced sensing. BBN plans to combine quantum-enhanced sensor data with machine learning algorithms to sharpen decision-making. This builds on RTX’s RAIVEN system, an AI-enabled electro-optical platform capable of detecting threats at five times the range and resolution of legacy systems. Integrating squeezed-light data with such AI tools could exponentially amplify situational awareness across multiple domains.
Finally, Quantum RF synthesis plays a crucial role. INSPIRED incorporates custom modules that precisely regulate light-matter interactions across wide radio frequency ranges—from 100 MHz to 10 GHz. This capability is essential for tracking weak, low-signature RF emissions, such as those produced by enemy radar or communications systems, particularly in contested electromagnetic environments.
Battlefield Impact: From Navigation to Hypersonic Defense
The potential military applications of INSPIRED are profound. In aerial domains, stealth aircraft outfitted with quantum infrared search and track (IRST) systems could detect cruise missiles and drones with twice the range of current sensors—without revealing their own position. Underwater, quantum magnetometers could map magnetic anomalies with unprecedented accuracy, giving naval forces the upper hand in submarine detection. In space, squeezed-light sensors could enable persistent surveillance through ultra-compact, low-power satellite payloads, making constellations cheaper and more agile.
Table: Military Applications of Quantum-Squeezed Sensors
| Domain | Application | Operational Advantage |
|---|---|---|
| Air | Stealth aircraft IRST (Infrared Search/Track) | Detect low-observable threats (e.g., cruise missiles) at 2× range |
| Undersea | Quantum magnetometers | Track submarines via minute magnetic disturbances |
| Space | Low-SWaP satellite sensors | Persistent surveillance with smaller, cheaper constellations |
| Cyber | Quantum key distribution | Unhackable communications for forward-deployed units |
On land, the benefits multiply further. Special forces could deploy handheld quantum imaging tools to detect hidden explosives or visualize movements through walls without compromising their position. Meanwhile, micro-drones operating in GPS-denied environments could use quantum-enhanced LiDAR to navigate autonomously through urban canyons or dense forests. For missile defense, quantum sensors could track hypersonic glide vehicles even through the plasma clouds that render traditional sensors blind. These capabilities converge perfectly with the Pentagon’s Joint All-Domain Command and Control (JADC2) framework, which demands seamless data fusion across all operational domains.
Challenges and the Road Ahead
Despite its promise, the INSPIRED program faces formidable engineering challenges. One major hurdle is photonic circuit losses—as light travels through multiple components on a chip, maintaining coherence and minimizing attenuation is no small feat. Thermal stability is another concern; quantum properties are notoriously sensitive to temperature and vibration, which can distort signal integrity in rugged, mobile environments like fighter aircraft or armored vehicles.
Moreover, manufacturing scalability remains a key bottleneck. While lab prototypes can demonstrate the science, transitioning these designs into hardened, deployable systems that can survive real-world conditions—and be mass-produced—requires close coordination between research labs, defense contractors, and the semiconductor industry. Nevertheless, if INSPIRED meets its milestones, its technologies could find rapid insertion into existing DARPA programs like RAIVEN or the U.S. Army’s Future Vertical Lift platforms, establishing early dominance in the rapidly evolving quantum sensing domain.
Conclusion: The Quantum Edge
DARPA’s INSPIRED program is more than a research contract—it is a vision of warfare’s future, grounded in the principles of quantum mechanics. By compressing powerful light-based sensing into millimeter-scale silicon chips and suppressing the very quantum noise that limits all current sensors, RTX BBN is on the verge of redefining what machines can perceive. These advancements won’t just give the U.S. military better tools—they will give it entirely new modes of awareness.
As we enter an era defined by autonomous systems, artificial intelligence, hypersonics, and electronic warfare, the ability to see what others can’t—to pierce darkness, distance, and deception—could prove as strategically valuable as radar was in World War II or satellite reconnaissance during the Cold War. INSPIRED signals that the next frontier of dominance lies not just in air, space, or cyber—but in the quantum properties of light itself.
“Light is a powerful tool, but today’s sensors are limited by quantum noise. Our device suppresses these fluctuations to extract information never before accessible.”
— Dr. Michael Grace, Quantum Scientist, RTX BBN
