Blog Post

Fiber Optics for Daylighting

Fiber optics, that miracle of modern communications, can also be used to deliver natural light to spaces deep in a building. Last week I focused on tubular skylights, which provide a great way to bring daylighting into home offices, hallways, bathrooms, and other spaces. An aluminum tube that's highly reflective on the interior transmits daylight down through an unheated attic to the space below--delivering the light through what appears to be a fairly standard light-diffusing ceiling fixture. It's a great technology--especially with the relative low cost--but it has some limitations. You need a relatively straight shot, and it's hard to extend the tubes through living space to reach first-floor spaces in multi-storey buildings.
For those with deep pockets, "active daylighting" using fiber optics provides a way to bring daylight deep into a home or commercial building--beyond the reach of tubular skylights. I know of two companies that are offering this technology: the Swedish company Parans Solar Lighting, AB (through its U.S. distributor HUVCO Daylighting Solutions), and the Himawari Solar Lighting System from La Foret Engineering Company, Ltd. in Tokyo, Japan. Here's how the Parans system works: On the roof or an outside wall, there's a one-meter-square collector (the SP2) with 62 separate Fresnel lenses that track the sun as it moves across the sky. The SP2 uses about 2 watts of electricity to operate this tracking, which is controlled by a photosensor and microprocessor.
Each of the lenses concentrates the sunlight into a tiny optical fiber, just 3/100ths of an inch (0.75 mm) in diameter. Bundles of 16 of these optical fibers are aggregated into cables (four from each SP2) that are about a quarter-inch (6 mm) in diameter. These cables can be run up to about 65 feet (20 m) to bring natural light to interior spaces quite distant from the roof or windows. The cables can be run through interior wall cavities, ceiling plenums, or wiring chases, and their bending radius can be as tight as two inches! The greater the length, the greater the light loss: at 33 feet (10 m) 64% of the light is delivered; at 65 feet (20 m), only 40%. In the spaces where light is to be delivered, various fixtures are available. These include spotlights, fairly conventional-looking ceiling fixtures, and some hybrid fixtures that include both daylighting and high-efficiency fluorescent lighting. Some fixtures are served by just one optical cable; others by two or four.
The Parans system is far from inexpensive, with a system starting at about $10,000 for one SP2, four optical-fiber cables, and four fixtures, plus installation. To date, about 20 of these systems have been installed in the U.S., according to HUVCO. Now, if you think that's expensive, there's another system available, at least in Japan. The Himawari Solar Lighting System (named after the Japanese word for sunflower) is a similar, but larger, fiber-optic system that uses tracking Fresnel lenses to capture sunlight and distribute it through a building. The product was first demonstrated in the late-1970s, and over 1,000 of these systems have been installed in Japan and Western Europe since then. Larger installations can cost over $100,000. Distributed daylighting through optical fibers is an exciting high-tech approach to making use of natural light. If prices come down, this could become a much more practical strategy in the future. One interesting issue with distributed daylight, according to an expert I spoke with, is that the color of the light changes throughout the day. In the early morning and late afternoon, it can be distinctly orange, while in the middle of the day, it can be quite blue, which gives the light a cool feeling. Some will find this annoying, while others may appreciate the experience of light quality changing during the day--as occurs outdoors. For more information on Parans Solar Lighting, contact HUVCO at 800-832-6116. I was unable to determine whether the Himawari is available in North America, but will provide that information in a comment if I hear back from the company. I invite you to share comments on this blog. Alex Wilson is the executive editor of Environmental Building News and founder of BuildingGreen, LLC. To keep up with his latest articles and musings, you can sign up for his Twitter feeds. Photos: Parans Solar Lighting

Published May 11, 2010

(2010, May 11). Fiber Optics for Daylighting. Retrieved from

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July 9, 2019 - 5:54 am

Is there any progress in cost lowering , for sunlight transfer , from rooves to internal spaces ? Currently assisting an architect with a large scale light transfer where we have available 18,000 sq ft of roof . contact me if this is of interest to inventor or researcher . I am contactable : email @ petersfield hotel dot com . thanks .

March 29, 2019 - 3:20 pm

I've been waiting at least 20 years for large scale development of fiber optic lighting for homes and buildings.  Forget about the cost of tracking and funneling sunlight---couldn't you light a whole house with just one bright bulb in a reflector box?   I'm starting a big project designed to possibly be off-grid, in an area remote enough to worry about power loss, and planning a large solar array for many buildings, ranging from several cabins to three homes to a large community building to a large indoor riding arena and barn.  The amount of money I could save by not having to engineer my solar system to do all of that lighting is astounding even without the solar collection aspect.

Why is the concept so unknown and why are the materials still so expensive?  I would have thought the enviros would have been all over this years ago, and costs would have come down as usage went up.  But all I ever see is accent lighting, pool lighting, ads and décor lighting.

March 19, 2019 - 10:53 am

Cost and what products are available ?
Possible going into business?

November 25, 2018 - 4:07 pm

Hmm. I don't know if I saw the same program about Himawari, or if it was something else--thought I remembered it was an episode of 'Believe it or Not.' For me, it was intriguing, the vegetation shown, which was lush and, as I recall, underground. Well, that was 40-odd years ago, so I may not remember correctly.

I'm looking at fiber as a means of creative lighting, tayloring an 'environment' around the house, using the fibers in a creative way. I'm stunned, as was the other poster, that this hasn't been radically commercialized. "Real light, inside, anywhere, creative presentation allowed." I can even see it being set up that the light gets run through a prism (well, I don't know if this would work, but it's an interesting mental plaything) and that the results are used to manipulate interior environment.

So, I see that cost is a holdup. There has to be more to it than that. In fact, my guess is that cost is only a small fraction of the holdup. Someone in the industry want to comment? 

September 10, 2017 - 9:05 am

I am interested in to minimise pollution and use natural resources

August 22, 2017 - 2:44 am

I want to know about the projects that is going on on solar lightning using fibre optics. Please send me details on my email address

June 2, 2010 - 5:53 am

Fiber optics is a part of applied science and is mainly used in communications. The sensors are specially designed fibers, which are used here to get the daylight effect. Thanks for the info.

May 26, 2010 - 5:00 pm

These tomatos must be 100 000 $ per pound!

May 6, 2011 - 3:39 am

just read this old post of year 2010 about optical fiber system, we are now assisting the Himawari optical fiber daylighting system to expanding their market

Since you only mentioned the Himawari is expensive at US$100,000, but you did not tell what items are inclusive, this is not too fair to Himawari, this US$100,000 can be just indicated the content with a set 12 lens outdoor unit, plus two nos. 150m optical fiber cables (each 492ft), wow, the length of optical fiber cable is just too long beyond your thought.

we are trying to provide some pricing idea with the similar length 20m optical cable which is about the max length from Parans, our list price are about US$25,000 for a set 12 lens outdoor unit plus 2 pcs each 20m cables with two lamp fixtures.

Advantages: you also totally neglected the advantages when talking about Himawari;

Based on Himawari's test report, the run of single optical fiber cable can be at 170m (557 ft) with light transmissivity efficiency 65.2%, this is far far better than any competitor at 40% left at only 20m, I rather install Solatube, the Solatube 21" dia efficiency at 20m is still much higher than 40%, but Solatube is then much cheaper.

pls email us if you needed any more technical information.

May 6, 2011 - 6:35 am

my last Posted 5/6/11 7:39 AM by Thomas

this is our email:

May 18, 2010 - 6:14 am

I remember watching a PBS program as a kid about the Himawari system. They were growing tomatoe plants in the center core of a high rise building, and the only light provided was through the fiber cable. I've been waiting for a commercial application ever since- wonder why it isn't progressing faster?

November 24, 2010 - 9:33 pm

Another great advantage of fibre optic lighting is that the fibres and/or end fittings can be permanently sealed in place, without having to worry about access to change bulbs.