Quantum photonic integrated circuits

Quantum photonic integrated circuits will play a key role in the coming quantum age, providing compact, scalable and high performing platforms for a host of new technologies.

Quantum technology promises exotic applications like uncrackable encryption, gravitational sensing and solutions to computing problems otherwise unsolvable in human time-scales. To do so, it will harness quantum physics – the radically different laws that govern the world of very small things like atoms and photons.

Photons offer a relatively easy way of establishing and maintaining the states required for quantum operations. And have the relative advantage over their alternatives of being far less effected by electromagnetic interference in their environment. Systems that use photons to carry out quantum operations are known as quantum photonic systems.

The advantage of photonic integrated circuits for quantum photonic systems

Experimental quantum photonic systems often rely heavily on bulk components and large optical benches. These are orders of magnitude too bulky, and too fragile, expensive and unscalable for widescale adoption.

Integrated quantum photonics overcomes these barriers by integrating miniaturized optical systems onto a chip – a photonic integrated circuit (or PIC), delivering huge benefits for quantum systems, including:

a photonic integrated circuit chip for quantum applications

PICs are inherently scalable because of high levels of integration

Compact systems

PICs integrate optical components on a chip that would otherwise crowd an optical bench meters across.

High levels of integration

With integrated light sources, detectors and in/out couplings, PICs make it possible to build complex systems that are relatively easy to connect and control. Cryostatic control of devices, for example, is made easier by integrating optical fibres for remote device control and communication.

Reduced power consumption

In high volume or highly distributed applications like sensing and communication, management of power consumption is key. Because PICs are smaller and more highly integrated than bulk optical systems, they often consume orders of magnitude less power.

Stability and robustness

PICs are made using advanced lithography processes. These enables the fabrication of components with an alignment accuracy of tens of nanometres. And as integrated solid-state devices, they are inherently robust, providing the mechanical and optical stability required for sensitive quantum systems.


The methods used to manufacture large numbers of PICs on a “wafer” of substrate lead to huge reductions in manufacturing cost and time and are highly scalable.

Silicon nitride benefits for quantum integrated photonic circuits

A silicon nitride chip with different wavelengths of light

Silicon nitride PICs have excellent compatibility with a wide range of light sources

As a quantum photonic material, silicon nitride, and in particular LioniX International’s TriPleX® platform, has particular advantages.

Low losses

In quantum photonic technology, effective performance often relies on controlling individual photons. Because of this, it is especially important to control optical losses. This is where silicon nitride waveguides excel.

TriPleX® offers a best-of-both-worlds combination of low propagation losses and low bending losses, even in tightly curved waveguides, using on-chip tailoring of modefield confinement. This makes for PICs with both low losses and denser component architectures.

Broad compatibility

The broad transparency range of TriPleX® waveguides offers further advantages for quantum applications, enabling the integration of (single photon) light sources for schemes including spontaneous parametric down-conversion, spontaneous four-wave mixing sources and the integration of quantum dots.

Engineered for integration

Quantum applications present challenging integration issues relating to their extreme sensitivity to their surroundings. LioniX international’s patented waveguide geometry addresses these challenges by allowing very precise control of modefield diameter. This enables effective coupling of light to fibres, grating and free space interfaces for precise control and readout of quantum PICs.

Reconfigurable PICs for quantum processing

Quantum photonic processing is based on networks of switchable logic gates and requires solid state, low-loss components that can be switched or tuned. Here, we offer two types of standard actuators capable of a full  phase shift: Thermo-optic actuators for very low loss actuation and much lower power stress-optic actuators enabling GHz range actuation.

Highly qualified quantum building blocks

TriPleX® is a mature platform. It harnesses the benefits of silicon nitride integrated photonics. The platform supports a wide array of highly qualified building blocks, to offer you ready-made solutions to quantum systems engineering challenges. Building blocks include solutions for integration of light sources and detectors, high Q factor cavities, integrated tunable lasers, beam splitters, combiners and on-chip actuators.

Integrated quantum photonic circuit development at LioniX International

The world’s largest quantum photonic processor

quantum photonic processor chip using silicon nitride

LioniX International silicon nitride waveguides enable the world’s largest quantum photonic processors

The world’s largest quantum photonic processors are designed by LioniX International’s quantum computing partner QuiX Quantum BV. The record-breaking programmable chips are manufactured by LioniX International using TriPleX® waveguides. The companyt makes use of integrated thermotic phase tuners to enable a processor with very high coherence lengths.

QuiX Quantum leads the way in developing processors with the largest number of qmodes (an equivalent to qubits) in the world, with the ambition of going from the current 20-modes to 50 and more.

Importantly, QuiX Quantum offers its processor as a turnkey solution enabling operation almost out-of-the box. This fully integrated solution, with driver electronics, cooling and housing is made possible by our vertically integrated approach to design and manufacturing.

Ultra-narrow linewidth tunable lasers

For quantum sensing, communications, system control/read-out and high precision optical applications, LioniX International develops and manufactures ultra-narrow linewidth tunable lasers in different wavelength ranges including c-band, 850nm, 780nm and 680nm. Provisional tests show these lasers to be capable of operation at cryogenic temperatures.

Integrated ion traps for scalable quantum computing

Drawing on the precision manufacturing and high levels of integration achievable with PICs, LioniX have fabricated chip-based ion traps for quantum processing rivalling the most sophisticated experiments. Read more about the ion trap designed by researchers at ETH Zurich.

How we can help your quantum photonic development

Early stage

For rapid turnaround proof of concept and prototyping with standard building blocks, a cost effective MPW run is the ideal solution.

Find out more about our MPW services

Technology development and scaling

A dedicated quatum photonic run enables you to tailor every aspect of your development. From building blocks and materials to assembly and packaging . Benefit from the full range of LioniX International vertically integrated development support.

Find out more about module development at LioniX International