OPTICAL COMMUNICATIONS LASER COMMUNICATIONS


Ground network limitations are overcome in space


Laser communication systems that rely on photonics components are being implemented in real-world trials


A


s the world’s data usage grows exponentially every year, the need for fast, reliable communications is


rising. Existing communication networks are largely based on ground-based infrastructure, whose expansion is limited by legal, economic or logistical challenges. Therefore, various organisations are working on bringing network infrastructure into air and space. Laser communication uses satellites


to transmit information through the atmosphere, between satellites or to and from space. The laser beams connect satellites with each other directly using inter-satellite links, but receiving stations can also be built on Earth, or even in cars or aeroplanes. The technique can transmit data more efficiently and up to 10 times faster than radio waves. It is also safer than radio communication because it’s much harder to intercept, making it particularly interesting


for defence applications. NASA and other space organisations are making gains in demonstrating large-scale systems to meet the mammoth data demands of their satellites. But the commercial sector is also bringing the technology to the mainstream. Sony, for example, launched a new


satellite communications company in summer 2022. Named ‘Sony Space Communications’ (SSC), the new subsidiary plans to adapt Sony’s existing optical disc technology – developed over the years for CD players and other products – to realise optical communications devices that are ultra-compact, lightweight, mass producible, and can withstand harsh environments such as space.


The small devices will use laser beams to connect micro satellites in low earth orbit (LEO), both with each other and with ground stations on earth. In summer 2022, Northrop Grumman successfully demonstrated a secure laser


communications system for low Earth orbit constellation constellations supporting the US military. The demonstration validated compatibility between commercially developed laser communication and secure US government encryption hardware, providing a baseline for proliferated space crosslink communications offerings. Mynaric supplied Northrup with the laser communication technology for this project. The company also recently delivered its Condor Mk2 communication terminals to Telesat Government Solutions, which will be mounted to satellites as part of a high-speed network the US Department of Defence is developing in low Earth orbit.


“NASA is making gains in demonstrating large-scale systems to meet mammoth satellite data demands”


Technological and integration challenges in developing laser communication systems


Speaking with Joachim Horwath, CTO and Founder, Mynaric


What technological challenges did you have to overcome to develop your laser communications system? There are always tricky things you must solve for hardware that is intended to work in space – especially for optical equipment, like our terminal, where optical surfaces must have nanometre precision and the alignment of components


must maintain micrometre precision throughout a large temperature range and lifetime. However, how to do that is fairly well understood. The real challenge is how


to build eight or more such complex systems a day in a very cost-efficient way. To succeed in that we needed to start early in the design. Questions like how few optical surfaces do we need to guarantee better than diffraction limited operation across a wide field of view, or how to best use photonic integrated circuits or to get rid of mechanisms wherever possible, need to be answered. Improving the SWaP (size, weight, and power) of our


terminals by about 30% compared to our previous generation Condor Mk2 terminals was almost a byproduct following this design for manufacturing approach. In that way we were able to realise significant size, weight, power, and performance advantages over its product.


What integration challenges were there and how did you overcome these? As the market demand increases for laser communications solutions, the biggest integration challenges come with serial manufacturing. Once a stable design is achieved, we g


Photonics Frontiers 2023 25


FRONTIERS PHOTONICS


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