It has been an interesting number of years in the fiber optics field. Since 1990, when fiber was starting to become the successor to microwave radio, there have been drastic changes. These changes have been both in the long haul area as well as the nearer-term Fiber To The Home, (FTTH) area. Having been mostly involved in the long haul side, this article addresses that perspective.

Flashing Lasers
Staring in 1990, fiber optics was new and exciting, though few outside of some esoteric academic circles truly understood it. A really fast, high bandwidth system was one that was measured in kilo or megabits per second. We all knew that there were glass "wires" in the ground that carried communications traffic and that it was a higher bandwidth than our good old three DS3 radios. But a laser flashing off and on? At the time no one was sure that it was going to be successful. Most technicians were still regarding their digital microwave radios as the primary focus of their jobs; fiber was an afterthought. As time went on, and the fiber equipment for transmitting more and more traffic was installed, the focus gradually shifted from radio to fiber. Slowly telecommunication companies started deactivating their radio midsections and were putting more and more emphasis on the fiber. There were a lot of reasons for this.

Reliable and Robust...
Fiber cable is mostly unaffected by weather or the radio "ducting" that drove the technicians crazy at times. There were a lot less outages due to electronic equipment failure than with the radios,and as a result, the cost profits to the company increased. At the time there were only minor government regulations to contend with--nothing like the FCC requirements for digital radios. More and more traffic was placed on fiber optic systems, which continued to grow with higher and higher bandwidths.

But Not Problem Free
But there were problems, as with any growing technology.One of the first problems identified was the dreaded "Fiber Cut." Telecommunications companies soon realized that, when a fiber on a linear system was cut, everything came to a sudden and complete standstill. Consequently, a lot of alternate routing on radios occurs while the fiber is being repaired. Since the radios were still loaded with traffic (48 DS3s), decisions had to be made about who was going to be dropped and who was going to be alternate-routed. In the beginning a fiber cable was run between two points and traffic was loaded on it. When that cable was cut, the customers had simply to wait until it was repaired. This is much like the adage of putting all your eggs in one basket. Often times,many different carriers were in the same trench. So a fiber cut could and often did affect more than one company, with no clear responsibility about who would going to fix it.

These problems were addressed in three major ways:

1. Training and Test Equipment
First of all, major emphasis was placed on the technician being trained and given the expensive equipment to splice the fiber.Schools sprung up offering all kinds of classes to teach both the technician and management how to handle a fiber cut. Some schools were good and are still around; others were ‘teaching’ in name only and have since passed away. Quite a number of contractors came forward offering their services for nothing but splicing. Today, some companies use contractor splicing exclusively and others still rely on their own technicians to do the splice work.

2. Prevention: Call B 4 U Dig
A second thrust was prevention, since it is much cheaper to keep a fiber cable from being cut than to bear the costs of repairing it. The loss of revenue during the repair, measured in thousands of dollars a minute and the potential loss of customers are significant cost considerations. The One Call system was revamped, strengthened, and grew by leaps and bounds. Construction companies, utilities, and anyone that dug in the ground were reminded over and over to "Call B 4 U Dig." There were even programs aimed at the residential homeowner to call before putting in a fence or fixing a driveway. While someone cutting a fiber cable cannot be totally prevented, what can be done is to try and contain the problem area. Radio, TV ads, handouts of caps and coffee cups to construction workers and technicians at each dig site, greatly increased the awareness level.

3. "Self-Healing" Through Alternate Routing
The third area was the concept of alternate routing.The concepts of physical diversity in fiber routes, ring networks, automatic ring switching,and mesh technology came into being. With this new equipment, a fiber break did not mean all the traffic was down. In the high dollar areas the traffic was automatically switched to a different path. In most cases, the customer was not even aware that the switch had happened. While this was not the end all of fiber cuts, it did give a lot of resiliency to the fiber networks. Now all the major, and some of the minor, carriers have "self healing" networks scattered throughout the country. The dreaded "fiber break" is still with us, but now it is not as crippling.

The future is Now
Yes, there have been major changes in recent years and, while I do not know what the next years hold in store, I am confident the technology will be different and exciting.

The Author is the Area Technical Coordinator for Broadwing Communications in Kansas City, Missouri. He has been an iNARTE member since 1988, and has Master Endorsements in RF and Non-RF.

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