Integrated Photonics for Wireless Applications: Enabling Free-Space Optics, 6G, and Beyond

Wireless networks are under growing pressure to support today's high data rates, and that pressure is only going to increase. Meeting it will require wireless architecture to make use of integrated photonics, which offers a new platform for scaling capacity. In this article, we explore how photonic integrated circuits (PICs) are already enabling the scale-up of wireless technologies.

Why Wireless Technologies Need an Integrated Photonic Layer

With more people connecting, a densification is occurring, resulting in the demand for more cells and network access points.^[1] We have reached a point now where the data growth outpaces the current spectrum’s efficiency gains while the investment required to build deeper, more capable networks keeps increasing.^[2][3]

With the crowding of the network expected to keep growing, we will start experiencing adverse effects due to the limited available bandwidth in our current RF spectrum. While engineers use techniques to improve efficiencies, fundamental limitations due to noise and finite bandwidth cannot be overcome. As systems approach those limits, further gains will come as a result of the use of more spectrum and denser infrastructure, which will drive deployment cost and system complexity upwards.

At the same time, this increasing network density also creates a power challenge. Larger antenna arrays, additional radio units, and complex signal processing all contribute to higher energy requirements, increasing both operational costs and thermal management demands.

Some of these limitations can be alleviated by the introduction of PICs in our current systems. PICs use photons alongside electrical signals to transmit and process information while meeting the size, weight, and power (SWaP) requirements. With PICs’ ability to beam steer and process high-frequency data with improved efficiency, they have already seen commercial deployment in some areas. 

Now, PICs can help us access another region in the electromagnetic spectrum, with the potential to change wireless technologies. 

Integrated Photonics in Wireless Applications

PICs complement RF electronics by performing optical functions before interfacing with conventional radio hardware. PICs enable information to be processed and transmitted using photons. Their multiple degrees of freedom and their ability to travel at the speed of light can not only help transform current technologies but also be the reason for new ones to emerge: 

Free Space Optical (FSO) communications 

In FSO communications, instead of RF signals, photons are used to carry information. Taking advantage of the different photonic degrees of freedom, new multiplexing/demultiplexing techniques can be implemented with PICs and hence allow for the parallel transmission and processing of data. Due to PICs’ ability to host different electronics and optical parts of a system, complete receivers and transmitters can be designed on a single chip, capable of fast, high-capacity, low-latency data transfer while reducing the terminal size and cost. 

PICs are transforming optical communication equipment by integrating functions such as wavelength-division multiplexing (WDM), modulation, routing, and detection onto a single chip. When incorporated into optical transceivers, PICs can reduce size, power consumption, and system complexity. In combination with FSO communication technologies, PIC-enabled transceivers can support building-to-building, vehicle-to-vehicle, and Earth-to-satellite links in situations where deploying fiber is difficult or impractical.

Apart from long- or mid-range communications, PICs enhance established indoor communication systems. Light fidelity (Li-Fi) technologies can complement existing Wi-Fi networks with their ability to transmit data at speeds at least an order of magnitude higher than Wi-Fi. PICs can be integrated with electronic systems to expand their capabilities, and many PIC technologies have already seen commercial deployment.

Wireless Links and High-Frequency Signal Generation for 6G/THz

With 6G aiming to achieve higher data rates, lower latency, and greater efficiency, PICs can play a pivotal role in its implementation. Their components can be tailored to have extremely high bandwidth, and therefore unconventional spectrums are being researched for their potential for 6G mobile networks. One of those is THz.

PICs can generate high-frequency signals, which are normally difficult to generate electronically. One of the techniques used for THz generation is photonic mixing, where beams of different frequencies are combined. PICs can have multiple laser sources integrated on them and can be a source for generating and transmitting THz signals. 

More elements can also be integrated on the chip, like modulators and antennas, making PICs ideal for THz generation and transmission. For example, by using multiple-input/multiple-output (MIMO) techniques alongside beam steering, PICs can push the limits of the transmission speed to reach even terabit-per-second data transfers.^[4]

Phased arrays are an integral element in RF systems. They allow for the formation of beam-steering modalities as they comprise multiple emitters or antennas whose output phase can be individually controlled. Inspired by these principles, optical phased arrays (OPAs) have been developed where optical interference is used to control the direction of light beams. Their implementation in free-space systems is highly beneficial due to the fast beam steering that can be performed electronically, without the use of any mechanical parts. OPAs are components found in receivers and transmitters today, making wireless links across different points a reality.

Integrated sensing and communications (ISAC)

ISAC is emerging as a key technology for future 6G and THz wireless networks, enabling communication and environmental sensing using a common waveform and hardware platform. In photonics-enabled wireless systems, the same photonic circuitry used for high-frequency signal generation can also support sensing functions, reducing system complexity while improving size and SWaP performance.

PICs can integrate laser sources, modulators, filters, optical beamformers, and true-time-delay elements on a single chip. Optical signals generated and processed on the PIC can be converted into high-frequency RF or THz signals using photonic mixing and high-speed photodetectors. These signals are then radiated by antenna arrays, allowing a common wireless waveform to be used for both data transmission and sensing.

The wide bandwidths available through photonic signal generation can improve both communication capacity and sensing resolution. At the same time, optical beamforming and delay-line techniques can enable precise beam steering and beam control across large antenna arrays. By analyzing reflected wireless signals, future ISAC systems may estimate range, velocity, direction, and channel conditions while simultaneously maintaining high-speed communication links.

As photonic integration continues to mature, PIC-enabled ISAC architectures could provide a compact and scalable platform for future wireless infrastructure, autonomous systems, satellite communications, and high-capacity 6G networks where communication and sensing are seamlessly combined.

Key Challenges for Wireless Systems Enabled by Integrated Photonics

While some of the technologies mentioned above are already seeing commercial deployment, there are challenges that still need to be addressed. 

Coupling losses at optical I/O

Optical I/O is one of the most critical parts of PICs, but they can still suffer from high coupling losses. In both free-space and fiber-based systems, these losses occur due to the mismatch between the chip’s waveguide and the medium of transmission outside the chip. While there is ongoing research on different coupling techniques, engineers will need to consider the design trade-offs for their specific applications.

Thermal sensitivity

Another bottleneck that current PICs face is their thermal sensitivity. Most of the components implemented on the chip can experience fluctuations in their performance due to changes in temperature. Apart from the temperature increase due to continuous operation, engineers will have to take into consideration the different temperatures of the environments that the PICs will be implemented in. 

For example, for wireless applications, their design requirements will become more complex in comparison to PIC operation in controlled fiber environments, with these requirements becoming increasingly more complex for applications like satellite-to-earth communications where extreme temperatures are reached.

Packaging and cost at scale 

One of the key constraints for FSO and 6G reaching commercial scale is the cost associated with packaging at large volumes. For PICs to be commercially implemented, they not only need to reach comparable or even superior range effectiveness to established RF systems but also need to have a comparable manufacturing cost. Currently, advanced PIC packaging remains costly relative to mature semiconductor processes.

Conclusion

Integrated photonics is already addressing specific, hard problems in free-space links and high-frequency signal generation, bringing a wireless technology that can keep up with the data demand. For the next wave of wireless technologies like 6G and satellite optical links to emerge, the remaining challenges need to be solved.

To learn more about PICs and their applications in next-generation wireless technologies, visit photondelta.com/photonic-chips/. 

References

1. Ericsson. Ericsson Mobility Report: June 2026 [Internet]. Stockholm (Sweden); 2026. Available from: https://www.ericsson.com/en/reports-and-papers/mobility-report/reports/june-2026
2. GSMA. Large traffic generators and network usage: myths and realities [Internet]. London: GSMA; 2024 Dec 6. Available from: https://www.gsma.com/about-us/regions/latin-america-and-the-caribbean/gsma_resources/ltgs_myths_and_realities/
3. J. G. Andrews, X. Zhang, G. D. Durgin and A. K. Gupta, "Are we approaching the fundamental limits of wireless network densification?," in IEEE Communications Magazine, vol. 54, no. 10, pp. 184-190, October 2016, doi: 10.1109/MCOM.2016.7588290. Available from: https://ieeexplore.ieee.org/document/7588290
4. Robyn Laskey. What is the bandwidth capacity of modern photonic chips? [Internet]. PhotonDelta. 2026 April 3. Available from:  https://www.photondelta.com/blog/what-is-the-bandwidth-capacity-of-modern-photonic-chips/