Every day, Mountain View buzzes with the activity of busy tech workers. Usually — as with Google, the city's largest company — their jobs rely directly on a fast, well-functioning broadband connection.

What many of them don't know is that a key inventor of broadband communication lives quietly among them — an elderly Chinese man who plays tennis in Cuesta Park, attends activities at Avenidas senior center and spends his evenings at home with his wife.

Dr. Charles Kao, 76, is the godfather of broadband thanks to his pioneering work with fiber optics in the 1960s, which revolutionized global communication. On Oct. 6, the Royal Swedish Academy of Sciences recognized his achievements by awarding him the 2009 Nobel Prize in physics.

Though he now lives with Alzheimer's disease, and often has trouble finding the words he wants to say, Kao still grasps the enormity of what his discoveries have done for the world.

"It is very, very significant," he said.

His work with fiber optics enabled many of the activities that now are often taken for granted, or even considered necessities, in everyday life: cable, on-demand television, the Internet.

Kao's wife Gwen likened the change to advancements in transportation. If old-fashioned telephone transmissions by copper wire were like an old dirt road, Kao has created a nine-lane freeway which now encircles the world.

"That's why everything goes so fast," she said.

As for winning the Nobel, "We never expected to have it," Gwen Kao said, noting that her husband's discovery "has been around for 40 years." Also, because her husband's work is applied physics, rather than "pure" theoretical physics the couple did not believe his work qualified for the prize.

So they were surprised, she said, at being awoken recently by the telephone at 3 a.m. "I thought, 'Oh we've got a junk call.'"

Instead the call was from Stockholm, only minutes before the official press conference announcing this year's laureates.

"I said, 'Wow. You mean, really?'" Gwen Kao remembered. "I kept saying, 'Oh my gosh, oh my gosh.'" Then she turned to wake her husband, and asked if he knew what the Nobel Prize was.

When he said he did, she replied, "Well, you've got it now."

Almost immediately, congratulatory e-mails began pouring in from all over the world — ironic, Gwen Kao said, considering that it's fiber optics allowing those instantaneous transmissions.

Ever since the announcement, the Kao's home near Cuesta Park has been inundated with reporters, especially from the Chinese media. Kao came to the U.S. from China by way of London, which is where he made his discovery while working for International Telephones and Telegraphs.

Though they had been visiting Mountain View for many years, it wasn't until this summer that the Kaos made the city their permanent residence.

They've always been an international couple, but "We decided we should be closer to the children," Gwen Kao said. Their daughter now lives in Sunnyvale, and they have a son in San Francisco. The family got together last Friday evening at a Cuban restaurant in Palo Alto to celebrate Kao's Nobel.

The award caps off a big year in the Kao family, including Dr. and Mrs. Kao's 50th wedding anniversary, which they celebrated last month.

"It's a long time coming," Gwen Kao said of her husband's award. She said that if you look at the history of the physics prize, the Academy often waits to see the full implications of a discovery before offering up the award.

"They like to be sure," she said.

Dr. and Mrs. Kao plan to attend the awards ceremony, which will take place in Stockholm on Dec. 10. But first, the couple will attend a ceremony at the White House next month, where Kao will meet President — and fellow Nobel laureate — Barack Obama.