How Light Waves Transfer Information: From Fiber-Optic Networks to Biological Light
Light is often described simply as something that allows us to see. Scientifically, however, light is much more than visible illumination. It is a form of electromagnetic energy capable of carrying remarkably complex information.
Modern civilization already depends on this ability. Fiber-optic internet, television remotes, barcode scanners, medical imaging systems, satellite links, and deep-space communication all use light to transmit data. At the same time, researchers have discovered that living cells naturally emit extremely faint particles of light known as biophotons or ultraweak photon emissions.
These discoveries raise an intriguing question: if engineered systems can use light to carry information, could living systems also use light as part of their communication networks?
The ability of light to carry data is firmly established. The exact role that naturally produced light plays in biological communication is still being investigated.
Light Is an Electromagnetic Signal
Light is part of the electromagnetic spectrum, which also includes radio waves, microwaves, infrared radiation, ultraviolet radiation, X-rays, and gamma rays.
These forms of electromagnetic energy differ primarily in their wavelength and frequency. Visible light represents only a small portion of the entire electromagnetic spectrum. Infrared light, which cannot be seen by the human eye, is widely used in fiber-optic systems, remote controls, sensors, and laser communication.
Light behaves as both a wave and a stream of discrete energy packets called photons. Because the properties of a light wave can be precisely altered, light can be organized into patterns that represent information.
In other words, light does not merely transport energy. When properly structured, it can also transport a message.
How Information Is Placed Onto Light
Information can be transferred using light by changing—or modulating—one or more properties of the light signal.
The simplest example is turning a light on and off:
- Light on can represent the number 1.
- Light off can represent the number 0.
Computers represent text, images, sound, and video using patterns of ones and zeros. When a laser or light-emitting diode switches between different states extremely quickly, it can transmit a stream of digital information.
Modern optical communication is considerably more sophisticated. Information may be encoded by altering:
Light intensity
The light may be made brighter or dimmer in controlled patterns. An on-and-off pulse sequence is a basic form of intensity modulation.
Pulse timing
The exact time at which each pulse arrives can represent information. The spacing between pulses can also be used as part of the code.
Wavelength
Different wavelengths—similar to different colors—can carry separate channels of information simultaneously.
Frequency
The oscillation rate of the electromagnetic wave can be altered or divided into channels.
Phase
Phase describes the position of a wave within its repeating cycle. Carefully controlled shifts in phase can represent different data values.
Polarization
Polarization describes the orientation of the electromagnetic field. Different polarization states can be used to carry additional information.
Advanced optical systems may combine several of these methods. This allows one light signal to carry far more information than a simple sequence of on-and-off flashes.
NASA describes optical communication as the use of light to transmit information through lasers. Its optical transceivers send and receive data by applying signal modulation to portions of the optical spectrum.¹
Information Is Found in the Pattern
A single photon does not ordinarily contain an entire photograph, document, or video. Instead, information is represented through organized patterns involving many photons.
The receiver evaluates characteristics such as:
- When photons arrive
- How many photons arrive
- Their wavelength
- Their phase
- Their polarization
- The spacing between pulses
- The overall sequence in which they are detected
The meaning is found in the relationship between these measurements.
This is similar to written language. A single letter carries limited information, but an organized sequence of letters can form a sentence. In an optical system, precisely organized patterns of light form the message.
The receiver must also understand the encoding system. It needs rules that explain how the signal begins, how bits are grouped, how errors are identified, and how the message should be reconstructed.
Therefore, successful information transfer requires more than a light source. It requires:
- A transmitter
- An organized signal
- A pathway or communication channel
- A receiver capable of detecting the signal
- A method for decoding its meaning
This principle becomes especially important when considering whether light may function as a biological signaling mechanism.
How Fiber-Optic Communication Works
Fiber-optic communication is one of the most familiar examples of information being carried by light.
A fiber-optic cable contains extremely thin strands of specialized glass or plastic. A laser or LED introduces modulated light into the fiber. The fiber guides the light along its length while limiting signal loss.
At the receiving end, a photodetector senses the incoming light and converts it into an electrical signal. Computer systems then decode that electrical signal back into the original information.
The process can be summarized as:
Digital data → modulated light → optical fiber → photodetector → reconstructed data
The light is not simply illuminating the inside of the cable. It is carrying an intentionally structured pattern.
International optical-fiber standards define characteristics such as signal attenuation, wavelength, chromatic dispersion, channel spacing, and physical interfaces. These properties influence how accurately and efficiently data can travel through an optical network.²
Sending Multiple Messages Through One Fiber
Optical systems can transmit several information streams through the same fiber by assigning each stream a different wavelength.
This process is called wavelength-division multiplexing, or WDM.
A useful comparison is a multilane highway. Each wavelength acts like a separate lane carrying its own traffic. The signals travel through the same physical fiber without becoming one indistinguishable message.
At the destination, optical components separate the wavelengths so that each data stream can be independently detected and decoded.
Dense wavelength-division multiplexing allows many narrowly spaced wavelengths to travel through a single fiber. This dramatically increases the amount of information that existing fiber-optic infrastructure can carry.
Light Can Transfer Data Without a Cable
Light does not always require a fiber. It can also transfer information through open air or space. This is called free-space optical communication.
In this type of system, a laser is aimed directly at a receiving telescope or detector. The light travels through the atmosphere or the vacuum of space rather than through glass.
Free-space optical communication offers several potential advantages:
- High data capacity
- Narrow, precisely directed beams
- Smaller communication equipment
- Lower power requirements in some applications
- Less opportunity for the signal to be intercepted outside the beam's path
The narrowness of the beam is also a challenge. The transmitter must be aimed at the receiver with extraordinary accuracy. Clouds, mist, atmospheric turbulence, smoke, dust, or physical obstructions may weaken or interrupt the signal.¹
Communicating Across Deep Space With Light
NASA has demonstrated that data encoded in laser light can be transmitted, received, and decoded across enormous distances.
NASA's Deep Space Optical Communications demonstration, carried aboard the Psyche spacecraft, successfully transmitted optical data at distances comparable to those between Earth and Mars. During the project, encoded laser signals were detected after traveling hundreds of millions of miles.
In December 2023, the system streamed an ultra-high-definition video to Earth from more than 19 million miles away at a maximum bit rate of 267 megabits per second. The demonstration later received spacecraft data from approximately 307 million miles away. Over the course of the project, ground terminals received a total of 13.6 terabits of data.³
These accomplishments provide a powerful example of how faint photons can remain meaningful even after traveling immense distances—provided that the signal is properly encoded, collected, detected, and decoded.
It is important to clarify that laser communication does not cause information to travel faster than radio waves. Both are forms of electromagnetic radiation and travel at the speed of light in a vacuum. Optical systems can deliver more information within a given period because they can support much higher data rates.¹
Light-Based Communication in Everyday Technology
Optical information transfer is already present in many familiar technologies.
Examples include:
- Fiber-optic internet
- Infrared television remotes
- Barcode and QR-code scanners
- Laser scanners
- Optical computer connections
- Security systems
- Pulse oximeters
- Medical imaging devices
- Satellite laser links
- Visible-light communication
- Li-Fi systems
In visible-light communication, an LED can flicker at speeds too rapid for the human eye to perceive. The light appears steady to a person, but a compatible detector can interpret the rapid changes as data.
This demonstrates an important concept: the absence of visible flickering does not mean that the light is unchanging or that it carries no information. A detector may recognize patterns that are far beyond normal human perception.
Living Organisms Also Emit Light
Scientists have established that living cells and organisms spontaneously emit extremely faint photons. This phenomenon is commonly called ultraweak photon emission, or UPE. The emitted photons are also frequently referred to as biophotons.
Ultraweak photon emission is different from obvious bioluminescence, such as the visible glow of a firefly. Biological photon emissions from humans, plants, and most animal tissues are far too faint to be seen with the naked eye.
Research indicates that much of this emission is associated with ordinary cellular metabolism, oxidative reactions, and electronically excited molecules. When these excited molecules return to a lower-energy state, some of their energy may be released as photons.⁴
The existence of ultraweak biological light is well documented. The larger question is what the light means and whether cells use any portion of it intentionally.
The Human Body Literally Emits Light
Using highly sensitive imaging equipment, researchers have photographed ultraweak light emitted by the human body.
A 2009 study used a cryogenic charge-coupled-device camera to examine spontaneous photon emission from human participants. The researchers reported that the human body directly and rhythmically emits light, with emission levels changing according to the time of day.
The intensity was approximately 1,000 times lower than the sensitivity of the naked eye.⁵
This biological light should not be interpreted as a visible aura. It is a measurable physical emission requiring highly sensitive, low-noise instruments and controlled darkness to detect.
Nevertheless, the finding demonstrates that the human body is not optically inactive. Living tissues continuously participate in processes that produce photons.
Do Biophotons Carry Biological Information?
The fact that cells emit photons does not automatically prove that those photons form an intentional communication system.
To establish biophoton communication, researchers would need to identify:
- A biological source that produces a structured signal
- A meaningful pattern or code within the emission
- A pathway through which the photons travel
- A cellular structure capable of receiving the photons
- A measurable biological response
- Evidence that the response is caused by the optical signal rather than another mechanism
Some experiments have produced intriguing results.
In one study, cell populations separated by glass appeared to influence one another despite the barrier preventing direct molecular exchange through the culture medium. The researchers examined whether photons passing through the transparent barrier could have contributed to the interaction.⁶
Other researchers have proposed that biophotons could potentially contribute to communication or information processing in the nervous system. These proposals involve possibilities such as photon production within neurons and the potential guidance of photons through biological structures.⁷
However, words such as possible, proposed, and potential are essential. The scientific evidence does not yet reveal a universally accepted biophoton language comparable to the clearly defined coding systems used in fiber optics.
Researchers have not established a complete biological dictionary explaining which photon patterns correspond to specific cellular instructions.
Biological Emission Versus Biological Communication
There is an important distinction between a signal that reflects cellular activity and a signal that directs cellular activity.
A photon emission may serve as:
A metabolic byproduct
The photons may be produced incidentally during oxidative or metabolic reactions.
A biological indicator
The intensity or spectral pattern may provide information about oxidative stress, metabolic activity, inflammation, tissue condition, or other cellular processes—even if the body is not using the emission as a message.
A regulatory signal
The photon may be detected by another molecule or cell and contribute to a biological response.
An intentional communication mechanism
The organism may actively organize photons into meaningful patterns that are transmitted and decoded.
The first two possibilities have substantially more supporting evidence. The third and fourth remain active areas of investigation.
It is possible for biological photon emission to provide useful information to an outside observer without functioning as an intentional language inside the body. For example, heat emitted by the body contains information about physiology, but this does not necessarily mean that the body intentionally uses every thermal pattern to send messages.
Scientific research must therefore distinguish between measurable correlation and purposeful communication.
Can Cells Receive Light?
Cells clearly possess molecules that respond to light.
Photoreceptor proteins allow the eyes to respond to visible light. Other light-sensitive molecules and chromophores can absorb particular wavelengths and undergo chemical or structural changes.
When a photon is absorbed by a compatible molecule, it can alter the molecule's energetic state. This may contribute to downstream biochemical events.
This provides a biologically plausible foundation for light-sensitive cellular responses. However, it does not prove that all naturally emitted biophotons are received as coded messages.
The receiver matters as much as the signal. A light pattern can carry information only when something is capable of detecting the pattern and responding to it.
Coherence, Randomness, and Organization
In communication technology, a useful signal must be sufficiently organized to be distinguished from background noise.
Random photon emissions may reveal that chemical reactions are occurring, but a communication signal generally requires greater structure. This organization may involve timing, intensity, wavelength, phase, polarization, or relationships between pulses.
The term coherence is sometimes used in discussions of biological light. In physics, coherence has precise meanings involving stable relationships between waves, particularly their phase and frequency.
It is important not to assume that every biological photon emission is coherent in this strict physical sense. Researchers must measure coherence rather than infer it simply because the light comes from a living system.
At the same time, the broader principle remains scientifically valid: greater organization within a signal can increase its ability to carry distinguishable information.
What Optical Technology Teaches Us About Biology
Engineered optical communication does not prove that cells communicate in exactly the same way as fiber-optic networks. It does, however, establish several important principles:
- Light can carry complex information.
- Very faint light can be detected with sufficiently sensitive instruments.
- Multiple types of information can be encoded into light.
- Different wavelengths can carry separate signals.
- A transparent or light-guiding medium can provide a communication pathway.
- A receiver must be compatible with the signal.
- Meaning depends on organization, detection, and decoding.
- A light signal may remain meaningful across very long distances.
These principles give researchers a useful framework for investigating biological photon emissions.
Rather than asking only whether the body emits light, scientists can ask more precise questions:
- Does the emission contain repeatable patterns?
- Do those patterns change with cellular conditions?
- Can other cells detect those changes?
- Does blocking the light alter the response?
- Are particular wavelengths more biologically active?
- Are there structures within the body that guide photons?
- Can photon patterns be separated from metabolic noise?
- Is the information merely measurable, or is it actively used by the organism?
A Science With Both Evidence and Open Questions
The science of light-based data transfer is well established. Every day, enormous amounts of human information travel through glass fibers and open space as organized patterns of photons.
The science of biological photon emission is also established. Living cells, tissues, and human bodies produce measurable ultraweak light associated with biochemical and metabolic activity.
What remains uncertain is the extent to which living organisms use these photons as a structured internal communication network.
Some research suggests that biophotons may influence cellular behavior or participate in signaling. Other evidence supports their use as indicators of metabolic and oxidative processes. Yet a complete biological encoding and decoding system has not been demonstrated.
The most scientifically responsible conclusion is therefore neither dismissal nor certainty.
Living systems produce light. Light is physically capable of carrying information. Cells contain molecules that respond to light. These facts make biological light communication a legitimate area of research—but not a fully solved mechanism.
Conclusion
Light is one of nature's most powerful information carriers.
By changing its intensity, timing, wavelength, phase, frequency, or polarization, a transmitter can place complex information onto a beam of light. A compatible receiver can then detect the photons and reconstruct the original message.
This principle powers fiber-optic networks, visible-light communication, satellite links, and NASA's deep-space laser systems.
Living organisms also emit ultraweak photons. These emissions provide measurable information about cellular activity, metabolism, and oxidative processes. Whether cells deliberately organize and decode these photons as a communication language remains an important scientific question.
The bridge between optical technology and biology should be approached carefully, but it is worthy of exploration. Modern communication systems demonstrate what light is capable of doing. Biophoton research asks whether living systems may already use some of those same fundamental properties in ways science is only beginning to understand.
References
- NASA — Optical Communication and Deep Space Optical Communications (DSOC) program overview
- International Telecommunication Union (ITU-T) — Optical fiber standards and recommendations
- NASA Jet Propulsion Laboratory — DSOC project results and data summary (2023–2024)
- Ultra Weak Photon Emission — A Brief Review, PMC / NIH (2024)
- Human photon emission: rhythmic and intensity study using cryogenic CCD camera (2009)
- Cell-to-cell communication through transparent barriers — biophoton interaction studies
- Biophotonic signaling in the nervous system — theoretical and experimental proposals