Enabling quantum-secured communications in India in the quantum computing era

Delivering a key quantum communication player in India

QNu Labs was founded in 2016 as a spin-off from Indian Institute of Technology (IIT) Madras. It has emerged as a key player in India's quantum market, specializing in fiber-based Quantum Key Distribution (QKD) systems for terrestrial and free-space applications. With nearly a decade of expertise in quantum physics and optics, the company has grown to over 120 members, excelling in both software and hardware development for QKD, as well as control systems for free-space applications, quantum random number generators (QRNG), and post-quantum cryptography solutions like quantum-VPN.

QNu Labs has achieved significant milestones, including its first QKD system sale to a Saudi Arabian research lab in 2018 and the delivery of a 50-km QKD system in 2019/2020. The company collaborates with global universities and relies on Exail for high-quality intensity modulators, a critical component in its DV-QKD systems.

QNu Labs’s Armos QKD system

Exail delivers core QKD system solutions

Since 2016, Exail has been considered by QNu Labs as one of its strongest suppliers, providing intensity modulators which are core elements in their DV-QKD system that works with DPSK protocol based on single-photon quantum state. Intensity modulators connected to the system seeder laser enable producing the pulses.

" We praise the high stability of Exail’s intensity modulator, as well as the high and stable extinction ratio, which are both crucial technical requirements for our QKD system, especially for the demodulation side.” says Rajesh Kumar Krishnan, Vice President-Engineering at QNu Labs “Other parameters like stability over a range of temperatures, and with fast variations, is very appreciated."

The high and stable extinction ratio is obtained by Exail’s intensity modulators thanks to a patented integrated Y-junction design. Exail also supplies drivers to QNu Labs, as an electro-optical modulator matching component. “” says K. Rajesh Kumar

“Getting a 20- or 30-dB amplification ratio was very challenging and Exail supported us on this also.” says K. Rajesh Kumar

Finally, Exail deliveres delay line interferometers (Exail’s DPSK demodulator “MINT”) based on micro-optical assembly technology to QNu Labs.

“We have had long discussions with the technical team of Exail to obtain the best extinction ratio possible with the delay line interferometer, as we believed in the technological strength of the micro-optics product line. Today the MINT products we receive show exceptional extinction ratio and excellent stability. They are used for both the terrestrial and the free-space QKD system we develop.” Says K. Rajesh Kumar “The hermetic sealing, the small footprint (compact, lightweight) and the temperature independent extinction ratio of Exail’s product are really appreciated.”

“Our team is always keen to learn about the latest solutions offered by Exail for QKD and quantum technology, for example electro-optical modulators that combine both intensity modulation and phase modulation functions into a single package (Exail’s MXIQER).” Says K. Rajesh Kumar

Exail’s customers relationship is celebrated by QNu Labs, especially the technical support:

“The constant feedback offered over several years is what we like in the customer relation with Exail. Their technical team has always been keen to improve itself, by confronting to our feedback in a win-win situation.” Says K. Rajesh Kumar

QNu Labs found it necessary to have a partner that understands their technical requirements, and that accepts working with them until reaching the stringent performance expected, for example on the micro-optic assembly technology that Exail has been pioneering.

Exail is glad to participate in expanding the frontiers of quantum secured communications in India.