Distributed Acoustic Sensing – DAS

Are you looking for a reliable laser for your Distributed Acoustic Sensing interrogator? DAS systems are used in a wide range of industrial applications. They are installed across the globe, often in remote and harsh environments, which put high demands on the system. What kind of laser should you use to make a DAS system that you can simply install and forget?

Install and forget!

If you deliver DAS systems for pipeline monitoring, perimeter security, or border control (to name a few), then it is likely that your systems will be installed in harsh environments in remote places.

Wouldn’t it be nice if you could install the system and forget all about it? With our robust and reliable Koheras fiber lasers, you can.

Designed for real life

We understand that the laser is a key component in your interrogator. It dictates the sensitivity, the range, the reliability, and the failure rate.

Our Koheras lasers are designed for real life. We have combined the all-fiber distributed feedback design with field-proven components from the telecom industry to give you a robust, reliable, maintenance-free, and service-free laser.

When we say reliable, we mean a typical lifetime of more than 10 years and a return rate of less than 1%.

Over the last 20 years, our customers have deployed more than 15,000 Koheras lasers in the harshest environments. We have lasers on oil rigs, submarines, wind turbines, and even in space.

You do not have to worry about laser supply. We can deliver all the lasers you need when you need them. Every year, our customers deploy more than a thousand Koheras lasers across the planet.

Long-range and high accuracy

To obtain long measurement ranges, our customers typically look for lasers with a long coherence length and low noise to get a high dynamic range. With a Koheras laser, it is possible to obtain measurement ranges of up to 100 km which makes it easier for you to handle your system and lets you save money on equipment.

Ultra-low phase noise (or frequency noise) is a key laser parameter for the sensitivity and accuracy of the sensing system. The high sensitivity of the Koheras laser ensures an excellent detection of acoustic signals.

Due to their intrinsic low-noise design, you get sub-picometer stability and mode-hop-free performance. Do you want to mount them upside-down? No problem. The all-fiber design keeps the laser stable. Install them in the desert? No problem. Temperature changes do not affect stability. Take them for a ride? No problem. Vibration and noise do not distort the signals.

Pick the right laser

Koheras MIKRO industrial single frequency laserMost of our customers pick the BASIK MIKRO E15 for their DAS interrogator. Its narrow linewidth, long coherence length, and ultra-low phase noise make it ideal for applications such as DAS, vibrometry, wind LIDAR, Photon Doppler Velocimetry, and inertial sensing.

The BASIK C15 is our shot-noise limited laser for those special applications that demand extra-low intensity noise. Other customers use the BASIK X15 in applications such as down-the-well sensing, oil exploration, naval acoustic sensing, and submarine.

If you need a flexible system with more wavelengths, our Koheras lasers are a bit like Lego (although less colorful). You can combine lasers to get the system that best suits you. Use the Koheras ACOUSTIK rack integration to combine up to 16 Koheras BASIK fiber lasers and two matching BOOSTIK line card amplifiers. The ACOUSTIK provides power and control to all modules and you can add and change channels as needed.

References

Here are some publications where others describe their work within DAS, using our Koheras lasers.

And don’t miss the short article on how thousands of our low-noise Koheras lasers keep a large-scale data network secure, with SFO Technologies.

 

Features

  • ­Low phase-noise and long coherence length provide sensing distances of +100 km
  • Accurate pinpointing of intrusion or threat
  • Industrial reliability due to robust laser design
  • Designed for OEM-integration
  • Maintenance-free 24/7 operation

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Don’t know what DAS is?

Distributed Acoustic Sensing is a sensing system based on light. The system consists of an interrogator and some optical fibers. The optical fibers replace traditional discrete sensors and lets you measure sound along with its entire length.

The interrogator has a laser inside which sends light pulses into the optical fibers. Most of the light travels forward but some of it is reflected back to the interrogator.

Sound and movements from the environment affect the light. The interrogator analyses the reflected light to figure out what is going on and if it should send an alert. The ultra-precise detection reveals the exact position of the incident, eliminates uncertainties, and saves time.