Tingye Li Dies at 81 Played Crucial Role in Laser s Development

By DOUGLAS MARTIN

Tingye Li, an electrical engineer whose calculations in the early 1960s helped guide the development of the laser and propel the dizzying increase in the speed of fiber-optic communication, died on Dec. 27 in Snowbird, Utah. He was 81.

The cause was a heart attack while he was on a family ski trip, his family said. He lived in Boulder, Colo.

Lasers were in the early stage of development when Dr. Li and a colleague at Bell Labs, A. Gardner Fox, developed a computer simulation of how lasers produce the focused light energy that has transformed fields from medicine to space travel. They reported their findings in a paper published in 1961.

Dr. Arno Penzias, a former director of Bell, called their paper a tool kit for subsequent designers of lasers and other optical systems. He said it helped transform the “wonderful invention” of the laser — the word is an acronym for light amplification by stimulated emission of radiation — into “a practical communications platform.”

In essence, the researchers provided a mathematical model for how light bounces about inside a laser between two mirrors as it gathers energy, predicting factors like the shape and intensity of light beams. Alan Willner, an electrical engineering professor at the University of Southern California, called the work “the foundational teaching” on the innards of lasers.

“There aren’t many papers that help define a field, but this was one of them,” he said in an interview.

The research that led to nearly instantaneous communication by light waves was itself snail-like. Dr. Li and Dr. Fox had to write their own programs, punching them into decks of cards, for a room-size computer that was less powerful than a palm-size calculator today. The computer ran the program for two or three hours. A frequent error message meant that the researchers had to scour the cards for a single improperly punched letter, Jeff Hecht wrote in “Beam: The Race to Make the Laser” (2010).

Bell Labs was virtually unchallenged as the largest and most inventive laboratory in the world, having a hand in many of the 20th century’s most important inventions. Dr. Li, who wrote or helped write more than 100 papers, patents and books, led research teams at Bell for more than three decades.

Some of their work laid the groundwork for today’s broadband. One area of study was in finding ways to use light waves to convey information on optical fiber rather than copper wire or radio waves. Another team Dr. Li led developed optical amplifiers, which amplify an optical signal directly without the need to first convert it into an electrical signal.

Dr. Li was an early proponent of using the rare earth metal Erbium in the amplifiers, an improvement that helped raise their capacity more than a hundredfold.

“Tingye Li has shaped the lightwave network infrastructure we know today,” the Institute of Electrical and Electronics Engineers said when presenting him with its Edison Medal in 2009.

Li Ding Yi, as his name is transliterated from Chinese, was born in Nanking, China, on July 7, 1931. His mother, Lily, belonged to the first generation of Chinese women to receive a modern higher education. She became an activist for women’s rights.

His father, Chao, was a Chinese diplomat who was consul general in Vancouver, where Tingye attended middle school, and was later posted to South Africa, where Tingye earned an undergraduate degree in electrical engineering from the University of Witwatersrand. He earned a Ph.D. in electrical engineering from Northwestern University in Evanston, Ill.

Dr. Li joined the Bell Telephone Laboratories (later AT&T Bell Laboratories) in 1957 and worked there until 1998. He worked there with the Nobel Prize recipients Charles Hard Townes and Arthur L. Schawlow, who together invented the maser, which amplified microwaves the way lasers would soon amplify light.

“There was a lot going on and a lot of people helping each other,” Dr. Penzias said.

Dr. Li often quoted Confucius, though friends suspected he occasionally concocted his own learned sayings and then attributed them to the sage. He frequently went to China to help it develop optical communications. The Chinese Academy sent his family a letter at his death praising him for helping China “leapfrog to a higher level” in handling telecommunications traffic.

Dr. Li is survived by his wife of 56 years, the former Edith Wu; his daughters, Deborah Li Cohen and Kathryn Li Dessau; and four grandchildren.

In a speech on his 80th birthday, Dr. Li revealed that he had proposed marriage to his wife for their next life, after they are both reincarnated. She tentatively agreed, he said, if he behaved.

光纖通訊之父 中研院院士厲鼎毅病逝

紐約時報六日報導，「分波多工之父」、中研院院士厲鼎毅去年十二月廿七日病逝美國，得年八十一歲；中研院應用科學中心主任蔡定平表示，厲鼎毅是光纖通訊的「前緣」開拓者（pioneer），非常照顧後進，平時有運動習慣、身體很好，聽到他過世「相當意外」。

厲鼎毅一九三一年生於大陸南京，在美國西北大學獲得電機工程博士。母親曾是中國第一代受過現代高等教育的女性，後來積極推動女權；父親厲昭曾先後出任中國駐加拿大溫哥華及駐南非約翰尼斯堡總領事。

厲鼎毅在高錕發明光纖通訊後開始研究如何使用光纖通訊，在一九六○年代即發表多篇重要論文，蔡定平並形容他「成名很早」，當時發表的都是該領域的經典之作。

之後厲鼎毅進入美國貝爾實驗室，帶領最前線的光通訊研究，至一九八○年代最為興盛，可說是全世界光通訊高速公路的始祖。

蔡定平說，過去光纖裡只能跑一道光，厲鼎毅最重要的發明就是讓一條光纖中可以跑很多道光，大幅提升訊息裝載量，將光纖應用得「淋漓盡致」。

以通話為例，原本一條光纖只能承載一個人講的話，厲鼎毅讓一條光纖可以承載二百五十六、甚至四千多人的通話，隨著科技的發展，現在已經可以承載上萬人通話。

他表示，厲鼎毅提出很巧妙的光學元件，不同光透過元件可收攏成一道光，在光纖中傳輸，出了光纖再通過元件，又可分成很多道不同的光；原理類似白光通過稜鏡後，變成七色光。

由於厲鼎毅在光通訊領域貢獻卓著，一九九○年代已成為該領域權威，二○○九年獲美國電子電機工程師學會的「愛迪生獎」，當時該學會說：「厲鼎毅打造出我們如今所知的微波網絡基礎建設。」。

厲鼎毅在退休後四處提拔年輕人，尤其常幫助華人學生，近年也常來台灣演講，鼓勵學生投入光電領域。一九七○年代，厲鼎毅還曾擔任李國鼎時期的科技顧問，替台灣日後的半導體電子發展打下基礎。

厲鼎毅是唯一曾擔任過美國光學學會會長的華人，同時也是美國國家工程院院士、台灣中央研究院院士、中國工程院外籍院士。

原文參照：
http://www.nytimes.com/2013/01/07/business/tingye-li-instrumental-in-the-lasers-development-dies-at-81.html

2013-01-08．聯合報．A11．綜合．記者陳幸萱、編譯馮克芸