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Lidar (light detection and ranging) is pushing the boundaries of how we analyze, interpret, and understand both earth and space environments from afar – and G&H’s lidar solutions already underpin many international remote sensing projects and programs.
In practice, lidar is one subset of numerous sensing application areas in which we at G&H are active.
These include distributed fiber sensing, which enables optical fiber to be used as a continuous, real-time sensing medium to detect temperature, pressure, and vibration disturbances over long distances – for example in linear assets such as border fences and walls, oil and gas pipelines, and power and utilities networks.
However, lidar, with its ability not only to locate the exact position of these disturbances, but to sense remotely, rather than in situ, is gaining significantly in traction, and it’s a trend that is likely to continue.
As recent research from experts at the universities of Colorado and Delft asserts, ‘The role of lidar will be increasingly important in the future. Although there are many potentials for new lidar technology advancements, lidar activities are gradually shifting from technology developments to applications.’
These applications can be anything from wind turbine calibration to spectroscopic analysis of space gases and mineral deposits – and much more besides.
But as the application types and environments proliferate, so too does the scrutiny of the underlying technology and its design. How stable is it? How powerful? How accurate? How sensitive? How susceptible to signal noise, extreme temperatures, shock and vibration?
For OEMs, in particular, the question is also how advanced lidar and sensing technology are in terms of the availability not only of components, modules, and subsystems, but in the design expertise that ultimately informs how these systems will perform.
Let’s take a look at the demanding parameters photonics solutions must satisfy in a sensing deployment, and specifically for lidar.
Fundamentally, lidar is about transmitting light (or coherent laser light) in pulses through a medium (which can also be space, or the atmosphere), and receiving reflections of that light that convey data about an object’s speed, position, density, spectral composition, and other characteristics.
It therefore follows that for lidar to be reliable in any application, both the transmission and the reception elements must be optimized.
The demands here can be challenging. On the transmission side, sensing applications require extremely narrow spectral width and smooth, stable, tunable control of wavelength, but with scope to also combine and separate those wavelengths to maximize sensing permutations.
They require appropriately variable initial power input, but also strong amplification to enable sensing to take place over long distances (satellite to Earth, for example).
On the reception side, the emphasis must be on increasing sensitivity relative to power and bandwidth requirement, and to tolerate signal impairments.
Add in the application-specific factors, and the challenges grow exponentially. In space, for example, extremes of temperature are common, whilst the space vessels, vehicles and satellites in which lidar systems are mounted naturally encounter significant shock and vibration, not to mention radiation.
Even on Earth, excessive heat, cold and humidity are more than capable of either causing lidar components and systems to fail, or adversely affecting their precision.
How, then, does a lidar system stand up to these challenges and deliver what is required of it?
And how does this response not only benefit other forms of sensing too – including distributed fiber – but create a seamless environment from design to manufacture that supports the development of sensing applications across the board?
The most successful recipes start with the best ingredients, so at G&H our proven approach combines DFBs (distributed feedback lasers), narrow-linewidth light source, fused couplers, optical modulators, and erbium-doped fiber amplifiers (EDFA).
This combination delivers the control and narrow bandwidth over the light source required, but with integrated temperature control and an interface that enables OEMs to easily tune to custom wavelengths to suit the application in question – including for higher-bandwidth and higher-power configurations.
But it also delivers many further benefits, including:
In short, from components, to modules, to systems, for every demanding lidar and sensing application there is an appropriate response!
Of course, whilst the robustness, performance and quality of individual components is key, what ensures OEMs are able to deliver a lidar or other sensing solution that answers their customers’ pain points is a truly collaborative and application-specific design process.
Here, too, we are helping remote sensing OEMs to overcome their lidar and sensing challenges. By forming a design and manufacturing partnership with the OEM, subsystem design and full system manufacture are shared between G&H and the OEM, informed by the OEM’s own system design and end-user sales process, and its own understanding of its markets.
This partnership between the subsystem developer and OEM customers, with engagement early on in project lifetimes, ensures an optimum fit between customer requirements, the design process, and the components and subsystems manufacture that G&H assumes responsibility for.
With dedicated design teams for electronics (including complex PCBs), optical, and mechanical, G&H is also home to two cutting-edge manufacturing centers in the US and the UK.
Offering 8000m2 of production floor space, accredited to ISO 9001 and AS9100, ISO Class 6 and 7 cleanrooms, and fiber optic assembly facilities, these centers enable us to take support for lidar OEMs to the next level at every stage – from conception, to design, to manufacture.
G&H is changing the world with photonics – and when it comes to complex and mission-critical lidar and sensing systems, we know that collaboration always produces superior results.
The themes in this article are also explored in more depth in a recorded G&H webinar, (https://gandh.com/designing-photonic-subsystems-for-lidar-and-sensing).
Below, we capture some useful questions and answers from that session that help to articulate G&H’s expertise and offering in the lidar space.