What Is Laser Communications?

What Is Laser Communications?

Laser communication technology has been a widely used form of communication between people and machines since its development in the early 1960s. The most significant advantage of using laser communication is that it removes the need for any buried cables or broadcast rights. 

Laser communications is a communication method where a laser diode transmits a beam of information to a receiving beam. The most important condition needed for laser communication is a free, unhindered line of sight. Laser communication has more bandwidth than radio waves.

This article will explore the basics of laser communication and how we use it in everyday life. The real-world application that we will be focusing on is its use in space by NASA and other organizations. 

The Basics of Laser Communication

A video explaining laser communications systems and their components.

Laser light is a type of stimulated emission of radiation. The famous physicist Albert Einstein did not invent the laser, but in 1917 his work on the stimulated emission of radiation laid the groundwork for lasers. The term laser is “Light Amplification by Stimulated Emission of Radiation” (LASER).

Developed in the early 1960s, Laser Communication (LC) or Free-Space Optical Communication (FSO) is a wireless optical form of communication. It has become a significant part of many types of technology that require long-distance data transfer. The original laser was created using sapphire crystals and was considered very weak. 

In laser communication, infrared light is used instead of radio waves because infrared light utilizes closer, more compact waves for transmission. The two main items needed for effective laser communication are an unhindered line of sight between the transmitter and the receiver and the transmitting and receiving of the beams themselves.

Fiber-optic communication links use a similar form of transmission as laser communications. The most significant difference is that lasers can transmit information through free space, while fiber optics use cables. Laser communication bandwidth is much greater than Radiofrequency (RF), and LC waves are not faster than RF waves but can transmit potentially 100 to 1000 times higher amounts of data.

Over the last 60 years, this technology has been developed into something much more powerful. From Supermarket scanners and 3D Printers to the world’s largest and most powerful lasers.

Components For Laser Communications

Components For Laser Communications
Components of a typical laser description and how it works.

There is a multitude of components and materials used for creating communication lasers and required for their laser engines, filters, beam splitters, mirrors, waveguides, amplifiers, and light-emitting diodes, just to name a few.

Communication lasers are usually constructed from three principal components:

  • An active gain medium or laser medium such as a semiconductor.
  • An energy source, pump, or pump source such as electrical currents.
  • An optical cavity consists of reflectors of two or more mirrors that form an optical resonator for light amplification.

Semiconductor Lasers (diode lasers) can be the size of a grain of salt and are used in fiber optic communication. Optical communications use infrared lasers that are used to send data to and from space.

Many experts believe that laser communication is a solution to the ever-increasing need for higher bandwidth. Using lasers instead of radio waves allows for faster communication between parties. 

Main Types of Lasers 

Main Types of Lasers
Infrared light is radiation in the non-visible spectrum used in some communication lasers.

Lasers have become a crucial part of society, especially with current telecommunications. Every day we are using lasers somewhere in our lives.

  • Fiber Lasers
  • Gas Lasers
  • Liquid Lasers
  • Semiconductor Lasers 
  • Solid-State Lasers

Laser Communication in Space

Laser Communication in Space
Laser communications satellite.

Typically, laser communications have a range of several thousand miles, which is more than enough for communication between satellites. However, if you pair a laser with a beam expander or a telescope, it can cross millions of miles, allowing for interplanetary communication.

Incredibly, In January 1968, laser beams from Earth were successfully detected by the United States Surveyor 7 Spacecraft that landed on the moon with its television camera in a special test of laser-pointing techniques. In 1969 Ruby laser pulses reached and measured the distance from the earth’s surface to the moon by bouncing off the retroreflector placed by Apollo 11 astronauts.

Lasers have been used for communication in space for many years. However, the technology needed a lot of development to become widespread. Today, lasers are commonly used for linking satellites in space to the equipment on the ground.

How NASA Uses Laser Communication in Space

As valuable as laser communication is, this technology has yet to fully prove itself on larger scales before it’s implemented on long-distance spacecraft. In fact, major recent projects such as the James Webb telescope still use radio communication. Luckily, NASA has its hands busy trying to master laser communication.

On December 8, 2021, NASA launched a Laser Communications Relay Demonstration (LCRD) aboard a U.S. Department of Defense’s Space Test Program Satellite 6. This revolutionary move demonstrates how NASA can use laser technology to gather information more efficiently than other methods.

NASA has always used radio frequencies to communicate and relay information between satellites and other spacecraft. Though this form of communication has been successful, space exploration is advancing, and the need to send large amounts of data is becoming increasingly important. 

Laser communications use infrared waves instead of radio waves. Since infrared light has a shorter wavelength than radio waves, more data can be transmitted at a time. 

Increased Communication Transmission Speeds in Space

Increased Communication Transmission Speeds in Space
Illustration of the NASA (LCRD) Laser Communications Relay Demonstration satellite relaying data. Credits: NASA’s Goddard Space Flight Center

According to NASA’s LCRD mission fact sheet, it would typically take about nine weeks for a complete map of Mars to be transmitted from space back to Earth. Lasers allow NASA to cut that time down to about nine days. 

The use of lasers will give NASA missions data rates that are 10-100x better than what they can get using radio frequencies. One of the most significant advantages of this increase in data capabilities is a higher definition for videos and photos from space telescopes.

These photos are exciting for the public, but the high definition will also allow scientists to learn more about what they reveal.

Benefits of Laser Communications Reduced Size

Aside from the increase in data capacity, the use of lasers in space has a few other benefits. The equipment used to provide optical communication is physically smaller than that of radio communication.

This attribute is a crucial improvement, as size and weight are premium commodities when it comes to putting things into space. With a smaller size and weight, the amount of power needed to use the lasers is decreased. That leaves extra area for more and better equipment in satellites and rovers.

The decrease in weight will also result in less expensive launches, and the laser’s reduced power usage will allow the batteries of the spacecraft and equipment to last longer. Overall, laser communication makes for more efficient space exploration.

Everyday Uses of Laser Technology

A video about everyday uses of laser technology by NBC News Learn.

One of the most widely used applications of laser technology is barcodes. Before the invention of lasers, inventory had to be done by hand. There wasn’t a standardized way to track inventory across industries and companies until the barcode. This technology has revolutionized logistics across every industry and allows companies to move parts, products, and even paperwork much more efficiently. 

Another wide use of laser technology is through TV, computer, and phone screens. High definition and a clear picture are achieved through fiber-optic connections. These connections take a large amount of data and transmit it via laser light through cables.

Medicine has also embraced the power of lasers by using laser scalpels in surgery. When the tissues around an area are particularly sensitive, surgeons use lasers to make incisions, such as in the brain and eyes. One of the most common uses of this technology is LASIK eye surgery. Lasers have the benefit of offering higher precision and preventing accidental incisions. 

Optical storage is another important application of laser technology. CDs, DVDs, and Blu-ray discs all use lasers to store information. Optical storage use is on the rise again out of necesity and is needed again due to massive increases in data storage requirements. 

New data storage resources are needed for the future as they are being outpaced by exponential growth in data generation. The wide use of optical storage can be credited to its reliability, affordability, high capacity, and growing internet and cloud computing size.

Finally, one of the most recent use of this technology has been in 3-D printing. Before its invention, researchers had to pay a hefty price to model objects for testing. Now, laser technology is used in 3-D printers to scan the object’s dimensions and create a digital model.

Interesting Laser Technology

Quantum and monochromatic laser light are other interesting facts about lasers. Quantum Cascade Lasers and Quantum Well Lasers are able to emit light efficiently. The efficiency of quantum lasers is greater than a conventional laser diode.

Monochromatic laser light allows for communication across great distances because its light has very low divergence. Since only one color is used in the laser, the light becomes more coherent and directional. This ability lets the light travel further without separating. 

“The major difference between laser light and light generated by white light sources (such as a light bulb) is that laser light is monochromatic, directional, and coherent. Monochromatic means that all of the light produced by the laser is of a single wavelength.” 

Laser Fundamentals – Section 1 – Princeton EHS

Conclusion

What Is Laser Communications Conclusion
Albert Einstein teaching us about lasers.

We are now able to detect Lasers in space over 5 Billion Light Years from Earth. Recently the MeerKAT radio telescope, using a team of researchers has discovered a powerful megamaser – a radio-wavelength laser typical of colliding galaxies. This is the farthest laser or megamaser named the “Nkalakatha” found so far from Earth. A maser is like a laser but emits radio waves instead of visible light.

Laser technology on Earth has been around since the 1960s and has seen significant advancement over the last sixty years. Most people are exposed to laser communication every day through barcodes, screens, medical devices, and 3-D printing.

However, the technology shines when it comes to space exploration. Its ability to transmit large amounts of data over long distances has made it a vital tool for satellites and telescopes. NASA’s LCRD mission will demonstrate how this technology can be used in space by both government and commercial organizations. 

References:

John Mortensen

I was a project manager and am a technology and science enthusiast who loves to study the latest technology, such as AI, smartphones, headphones, and software.

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