Free space optics no laughing matter

The first time I heard of the technology I have come to know as free space optics was at a networking conference during the summer of 1998.

The first time I heard of the technology I have come to know as free space optics was at a networking conference during the summer of 1998. At that time, I had been covering the cabling industry for about a year, and was at a point where every time I learned something new about networking, it became increasingly clear to me how much I didn't know.

I attended this conference, which was held locally, with two colleagues. Free space optics, by that or any other name, was not on the conference agenda. The topic came up as a question from an audience member after a presentation that covered an entirely different topic—I'm 99% sure the topic presented was Gigabit Ethernet, because in 1998, every networking conference topic was Gigabit Ethernet.

Anyway, a conference attendee asked the speaker about the prospects of a technology he called "air optics," describing it as sending optical signals through the air rather than over a cabled fiber. After about 15 seconds, it became obvious that the man who asked the question clearly was the person in the room who cared the most about the topic. His "question" turned into an impassioned dissertation (some might say a tirade) about the capabilities of this developing technology.

Much to my surprise, the speaker to whom this question was first asked was also versed in "air optics," evidenced by the fact that he pointed out one or two of its limitations. The questioner/advocate acknowledged these shortcomings, which included rain and birds.

That was all I needed to hear.

On the car ride home with my colleagues, we howled with laughter over the ridiculous assertion that any network user would employ "air optics," which would be deployed in outdoor environments like rooftops, yet would fail to deliver a signal if a bird flew in its path.

For the next few years, I never thought about "air optics." Well, at least not seriously. Because I interacted daily with the colleagues who also attended that conference in 1998, every once in a while, we would reminisce about the foolish man touting air optics. And each of our conversations ended with the same punchline: birds.

Fortunately, a great many people took the concept much more seriously than I did in those years. While I anxiously awaited the arrival of specifications for the 1000Base-T protocol and Category 5e cabling systems, research-and-development teams were working to make the promise of through-the-air optical-signal transmission a reality. Today, it is just that.

The commonly accepted name for the technology is free space optics. Although it is a wireless form of signal transmission, it differs greatly from the 802.11 series of standards from the IEEE. I won't get into detail here this month, for two reasons. First, there is not enough space on this page to fully explain any single aspect of it. And second, we will devote the necessary space to the topic next month in a full-length feature article.

You should know that while beginning my research on free space optics for next month's article, I could not resist asking about the effect of birds on signal transmission. And I found out that, yes, birds are indeed still a factor that should be accounted for. But that fact was put into context because once I bothered to find out about the applications, implications, and realistic positioning of this technology in the market, I found the concept to be more laudable than laughable.

So, wherever you are, O wise attendee of that networking conference back in 1998, I offer you my humble apologies for poking fun at your belief in "air optics." And for those of you who are sincerely interested in the possibilities of deploying such technology in today's networks, pick us up again next month for detailed coverage.

Patrick McLaughlin
Chief Editor
patrick@pennwell.com

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