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高锟诺奖演辞《古沙递捷音》 [推广有奖]

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tt_winner 发表于 2009-12-11 01:57:13 |AI写论文

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Sand from centuries past: Send future voices fast 古砂递捷音

高锟夫人、高黄美芸前日代夫登台发表题为《古沙递捷音》的诺贝尔奖得奖人演说,缕述了这位科学家为梦想不断探索的点点滴滴,堪称千金难得的好教材。高锟夫人、高黄美芸前日代夫登台发表题为《古沙递捷音》的诺贝尔奖得奖人演说,缕述了这位科学家为梦想不断探索的点点滴滴,堪称千金难得的好教材。





非常遗憾,我丈夫高锟教授不能亲自来主持这个演讲。非常遗憾,我丈夫高锟教授不能亲自来主持这个演讲。作为他的至亲,我与你们站在一起向他致敬,并代替他主持这次演讲。作为他的至亲,我与你们站在一起向他致敬,并代替他主持这次演讲。他为自己获诺贝尔基金会肯定他的成就,并颁予他这个奖项而感到非常自豪,我们也身同感受,与有荣焉。他为自己获诺贝尔基金会肯定他的成就,并颁予他这个奖项而感到非常自豪,我们也身同感受,与有荣焉。

1966年,高锟发表了具有开创性的论文,为我们带来了今天无处不在的光纤通信。 1966年,高锟发表了具有开创性的论文,为我们带来了今天无处不在的光纤通信。四十三年以来,电话通信世界因此发生了巨大变化。四十三年以来,电话通信世界因此发生了巨大变化。这一伟大变革正源于高锟的执着,因为他在众人质疑声中仍坚持自己的信念。这一伟大变革正源于高锟的执着,因为他在众人质疑声中仍坚持自己的信念。

20世纪70年代,玻璃光纤的预产研究出现在美国维吉尼亚州罗阿诺克市的ITT公司(国际电话电报公司)。 20世纪70年代,玻璃光纤的预产研究出现在美国维吉尼亚州罗阿诺克市的ITT公司(国际电话电报公司)。在那段期间,高锟收到两封信,一封言辞严厉,谴责他打开了魔瓶,释放了瓶中恶魔;另一封来自中国一个农民,向他讨教有什么办法可以告诉远处的妻子给他送饭。在那段期间,高锟收到两封信,一封言辞严厉,谴责他打开了魔瓶,释放了瓶中恶魔;另一封来自中国一个农民,向他讨教有什么办法可以告诉远处的妻子给他送饭。这两封信分别预示了一种未来的人类生活图景,而今天这两种图景都已成为历史。这两封信分别预示了一种未来的人类生活图景,而今天这两种图景都已成为历史。

60年代,我们的孩子还很小。 60年代,我们的孩子还很小。高锟常常很晚回家,以至子女经常都要在餐桌前等着吃晚饭。高锟常常很晚回家,以至子女经常都要在餐桌前等着吃晚饭。我对他每天晚归感到很生气,我依稀记得他是这么对我说的:我对他每天晚归感到很生气,我依稀记得他是这么对我说的:

「别生气,我们现在做的是非常振奋人心的事情,有一天它会震惊全世界的。」 「别生气,我们现在做的是非常振奋人心的事情,有一天它会震惊全世界的。」
我略带讽刺地说:「是吗?那你会因此而得诺贝尔奖的,是吗?」我略带讽刺地说:「是吗?那你会因此而得诺贝尔奖的,是吗?」

他是对的,他的成果给通信界带来了一场惊天动地的革命。他是对的,他的成果给通信界带来了一场惊天动地的革命。

早期研究

1960年,在伍尔维奇的标准电话与电报工作了一段时间后,高锟加入了附属英国ITT的标准电信实验室(STL)。 1960年,在伍尔维奇的标准电话与电报工作了一段时间后,高锟加入了附属英国ITT的标准电信实验室(STL)。他在标准实验室的工作,主要集中在微米波传输系统,目的是要改良当时通讯基础设施的传输容量。他在标准实验室的工作,主要集中在微米波传输系统,目的是要改良当时通讯基础设施的传输容量。

35到70千兆赫的微米波可能有更高的传输容量,但是具体情况不明,困难巨大,因为在这样的频率范围,光束会发散或被大气吸收,无线电波无法传输长距离,光波需要借波导引导。 35到70千兆赫的微米波可能有更高的传输容量,但是具体情况不明,困难巨大,因为在这样的频率范围,光束会发散或被大气吸收,无线电波无法传输长距离,光波需要借波导引导。上世纪50年代,低损耗环形波导(HE-11模)的研究工作刚刚起步,60年代开发了一个试验系统,投入巨额资金,积极计划把这个系统推至预研阶段,大大提高了公众对诸如视频电话等新电信服务的期望。上世纪50年代,低损耗环形波导(HE-11模)的研究工作刚刚起步,60年代开发了一个试验系统,投入巨额资金,积极计划把这个系统推至预研阶段,大大提高了公众对诸如视频电话等新电信服务的期望。

高锟加入了卡博维克博士(Dr.Karbowiak)领导的长距离波导研究组。高锟加入了卡博维克博士(Dr.Karbowiak)领导的长距离波导研究组。他看到真实的环形波导,兴奋无比。他看到真实的环形波导,兴奋无比。那时,他的任务是为微波和光信号寻找新的传输方法。那时,他的任务是为微波和光信号寻找新的传输方法。他同时运用几何光学和波动说以求更深入理解波导问题,在当时,这是一个全新的想法。他同时运用几何光学和波动说以求更深入理解波导问题,在当时,这是一个全新的想法。其后,他上司建议他在标准实验室工作期间同时攻读博士学位。其后,他上司建议他在标准实验室工作期间同时攻读博士学位。高锟于是在伦敦大学学院报读博士课程,并在两年内完成了他的论文《准光学波导》。高锟于是在伦敦大学学院报读博士课程,并在两年内完成了他的论文《准光学波导》。

1959年激光的发明给了电信业极大鼓舞,认为光通信很快就能实现。 1959年激光的发明给了电信业极大鼓舞,认为光通信很快就能实现。相干光可以成为新的信息载体,相比于点对点的微波系统,它可以提供十万倍的信息容量。相干光可以成为新的信息载体,相比于点对点的微波系统,它可以提供十万倍的信息容量。这个结论是由简单比较它们的频率得来:光的频率是300太赫(3×1014赫),微波的频率只有3千兆赫(3×109赫)。这个结论是由简单比较它们的频率得来:光的频率是300太赫(3×1014赫),微波的频率只有3千兆赫(3×109赫)。

光通信大有与环形波导系统争一日长短之势,但环形波导系统在当时仍然稳占上风。光通信大有与环形波导系统争一日长短之势,但环形波导系统在当时仍然稳占上风。 1960年,激光技术才刚起步,全球只有数间研究所进行过一些实验,未有足够数据证实光通信的可行性。 1960年,激光技术才刚起步,全球只有数间研究所进行过一些实验,未有足够数据证实光通信的可行性。光通信尚未成气候。光通信尚未成气候。

但高锟仍然认为激光通信具有巨大潜力。但高锟仍然认为激光通信具有巨大潜力。他对自己说:「我们怎么可以断定激光没有作为?如果光通信仅仅停留在理论阶段,那实在是太可惜了。」他对自己说:「我们怎么可以断定激光没有作为?如果光通信仅仅停留在理论阶段,那实在是太可惜了。」

他提出两个问题:

1.红宝石激光是否光通信的合适光源? 1.红宝石激光是否光通信的合适光源?

2.在这样的波长范围,有什么物质具有足够的透明度? 2.在这样的波长范围,有什么物质具有足够的透明度?

那个时候,只有两个研究组开始从事光通信传输方面的研究,其他的研究组则从事固态和半导体激光器的研究。那个时候,只有两个研究组开始从事光通信传输方面的研究,其他的研究组则从事固态和半导体激光器的研究。激光在光频范围会发出相干的辐射,但要利用相干光作为信息的载体,即使非绝无可能,也十分困难。激光在光频范围会发出相干的辐射,但要利用相干光作为信息的载体,即使非绝无可能,也十分困难。要真正实现光通信,还有很多重要的问题需要解决。要真正实现光通信,还有很多重要的问题需要解决。

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关键词:古沙递捷音 高锟诺 Centuries 伦敦大学学院 future 高锟诺 古沙递捷音

沙发
tt_winner 发表于 2009-12-11 01:58:04
关键的发现

1963年,高锟已在进行开放空间的氦氖(HeNe)激光传送实验;半导体和激光技术快速发展,令有关光通信的研究得以广泛开展。 1963年,高锟已在进行开放空间的氦氖(HeNe)激光传送实验;半导体和激光技术快速发展,令有关光通信的研究得以广泛开展。标准实验室的研究人员把激光远射,发现光点不停闪动。标准实验室的研究人员把激光远射,发现光点不停闪动。由于大气的波动,光点在几个光束直径的范围内跳动。由于大气的波动,光点在几个光束直径的范围内跳动。

研究人员也进行其他实验,以求重复或改良世界各地研究所的结果。研究人员也进行其他实验,以求重复或改良世界各地研究所的结果。比如说,他们进行了和贝尔实验室类似的共焦镜实验:将一系列凸透视镜以焦距相隔,排列起来。比如说,他们进行了和贝尔实验室类似的共焦镜实验:将一系列凸透视镜以焦距相隔,排列起来。即使在夜深人静,空气死寂的时刻,就算每隔100米重新聚焦,光束仍不能固定在镜片的有效孔径内。即使在夜深人静,空气死寂的时刻,就算每隔100米重新聚焦,光束仍不能固定在镜片的有效孔径内。

贝尔实验室曾利用气体透镜进行实验,但因无法绝对隔热以稳定气体透镜的外形,不得不放弃实验。贝尔实验室曾利用气体透镜进行实验,但因无法绝对隔热以稳定气体透镜的外形,不得不放弃实验。这些实验简直是缘木求鱼,无非是想找出长距离传输光线的方法。这些实验简直是缘木求鱼,无非是想找出长距离传输光线的方法。

在标准实验室,研究重心逐渐转向介电波导:用不导电的介电圆柱体,被空气包围,组成波导。在标准实验室,研究重心逐渐转向介电波导:用不导电的介电圆柱体,被空气包围,组成波导。卡博维克博士建议高锟和其他三名研究人员就他提出的薄膜波导进行研究。卡博维克博士建议高锟和其他三名研究人员就他提出的薄膜波导进行研究。

但薄膜波导的研究失败了:它对光的约束作用不足,光线在拐弯时会泄漏出来。但薄膜波导的研究失败了:它对光的约束作用不足,光线在拐弯时会泄漏出来。

其后卡博维克博士移民澳洲,高锟遂出任研究计划的领导,他随后建议对光线在介电材料的衰减机制进行研究。其后卡博维克博士移民澳洲,高锟遂出任研究计划的领导,他随后建议对光线在介电材料的衰减机制进行研究。

有几位研究人员专门研究如何量度低衰减透明物质的衰减程度。有几位研究人员专门研究如何量度低衰减透明物质的衰减程度。 George Hockham则与他一起研究介电波导的特性,因为他对波导理论感兴趣,所以集中研究光纤波导的容限条件;尤其是光纤电缆的体积容限和接合点光功率衰减的程度。 George Hockham则与他一起研究介电波导的特性,因为他对波导理论感兴趣,所以集中研究光纤波导的容限条件;尤其是光纤电缆的体积容限和接合点光功率衰减的程度。他们按部就班,研究玻璃纤维作为波导材料的物理和波导条件。他们按部就班,研究玻璃纤维作为波导材料的物理和波导条件。

此外,高锟还推动他的激光研究小组同事,进行有关近红外半导体激光器的研究,使这种激光器的发光特性配合单模光纤的直径。此外,高锟还推动他的激光研究小组同事,进行有关近红外半导体激光器的研究,使这种激光器的发光特性配合单模光纤的直径。单模光纤只容许单一光线或光模传递。单模光纤只容许单一光线或光模传递。激光器必须耐用,并且可以在室温操作而无需液氮冷却。激光器必须耐用,并且可以在室温操作而无需液氮冷却。所以,有关激光器的研究也是挑战重重,但在20世纪60年代初期,看似不着边际的研究还是可以得到支持的,只要耗资不是太巨大。所以,有关激光器的研究也是挑战重重,但在20世纪60年代初期,看似不着边际的研究还是可以得到支持的,只要耗资不是太巨大。

此后两年间,高锟领导的研究小组努力向目标进发。此后两年间,高锟领导的研究小组努力向目标进发。对材料的物理性和化学组成,在解决新发现的电磁波问题上,他们都欠缺经验,但仍取得可喜的进展。对材料的物理性和化学组成,在解决新发现的电磁波问题上,他们都欠缺经验,但仍取得可喜的进展。他们查阅文献、访问专家,以及向多家玻璃和聚合体材料公司搜查样本。他们查阅文献、访问专家,以及向多家玻璃和聚合体材料公司搜查样本。他们也研究有关的理论,并为进行一系列实验制定了测量的技术。他们也研究有关的理论,并为进行一系列实验制定了测量的技术。在他们设计开发出来的各种设备中,有一种是用来测量在材料内极轻微的亮度衰减,另一种则用于分阶模拟实验,以测量因机械缺陷而导致的亮度损耗。在他们设计开发出来的各种设备中,有一种是用来测量在材料内极轻微的亮度衰减,另一种则用于分阶模拟实验,以测量因机械缺陷而导致的亮度损耗。

高锟最终认定玻璃是可能的透明材料。高锟最终认定玻璃是可能的透明材料。玻璃是由亘古以来既廉价又用之不竭的沙粒做成的。玻璃是由亘古以来既廉价又用之不竭的沙粒做成的。

透明材料的光学损耗原因有三:(a)固有损耗;(b)外因损耗;(c)Rayleigh性散失。透明材料的光学损耗原因有三:(a)固有损耗;(b)外因损耗;(c)Rayleigh性散失。材料结构本身吸收红外线,造成固有损耗,因而限制了透明区域的波长;外因损耗是由于材料不纯净;而Rayleigh性散失则是材料结构不统一,导致光子散失的结果。材料结构本身吸收红外线,造成固有损耗,因而限制了透明区域的波长;外因损耗是由于材料不纯净;而Rayleigh性散失则是材料结构不统一,导致光子散失的结果。常见的玻璃产品如窗玻璃,因为透明度足够一般应用,所以没有人会深入研究至此。常见的玻璃产品如窗玻璃,因为透明度足够一般应用,所以没有人会深入研究至此。在与多位专家讨论之后,高锟最终得出以下结论:在与多位专家讨论之后,高锟最终得出以下结论:

1.必须将所有杂质,特别是铁、铜、锰等过渡元素,降低至百万分一以至十亿分一水平,以减少杂质损耗,但没有人知道是否可以降低至这样的水平。 1.必须将所有杂质,特别是铁、铜、锰等过渡元素,降低至百万分一以至十亿分一水平,以减少杂质损耗,但没有人知道是否可以降低至这样的水平。

2.高温玻璃相对于聚合体之类的低温玻璃冷却较快,其分布因而较均匀,有较低的散失性衰减。 2.高温玻璃相对于聚合体之类的低温玻璃冷却较快,其分布因而较均匀,有较低的散失性衰减。

与此同时,微波的模拟实验也宣告完成。与此同时,微波的模拟实验也宣告完成。根据其波模、其端对端偏差容限以及其直径偏差容限,介电波导的特征得以完整界定。根据其波模、其端对端偏差容限以及其直径偏差容限,介电波导的特征得以完整界定。理论和模拟实验都证实该方法是可行的。理论和模拟实验都证实该方法是可行的。

他们就此写了一篇题为《为光波传递设置的介电纤维表面波导管》的论文,投到《英国电子工程师学会学报》。他们就此写了一篇题为《为光波传递设置的介电纤维表面波导管》的论文,投到《英国电子工程师学会学报》。经过寻常的评审和修改过程,论文于1966年7月刊出──那一天现在被视为光纤通信的诞生日。经过寻常的评审和修改过程,论文于1966年7月刊出──那一天现在被视为光纤通信的诞生日。



论文

论文以圆形截面光纤中模式性质的简短讨论作为开卷。论文以圆形截面光纤中模式性质的简短讨论作为开卷。

论文紧接集中讨论被认定是应用光纤于通讯上的主要障碍:材料特性。论文紧接集中讨论被认定是应用光纤于通讯上的主要障碍:材料特性。那时候,即使是最透明的玻璃,损耗也高达200dB/km,这使得信号在玻璃中只能传输几米──谁都知道厚玻璃是不甚透光的。那时候,即使是最透明的玻璃,损耗也高达200dB/km,这使得信号在玻璃中只能传输几米──谁都知道厚玻璃是不甚透光的。

但是该论文指出,散失造成的固有损耗可以低至1dB/km,因而光讯号在实际距离上的传输是可能的。但是该论文指出,散失造成的固有损耗可以低至1dB/km,因而光讯号在实际距离上的传输是可能的。限制传输的主因是杂质:在这些波长范围主要是二价和三价的铁离子。限制传输的主因是杂质:在这些波长范围主要是二价和三价的铁离子。引用论文中的话:「只要把铁杂质的浓度降至百万分之一,可以预期制造出在波长0.6微米附近损耗为20dB/km的玻璃材料。」简而言之,只要材料够「纯净」,几百米厚的玻璃板也可以看穿。引用论文中的话:「只要把铁杂质的浓度降至百万分之一,可以预期制造出在波长0.6微米附近损耗为20dB/km的玻璃材料。」简而言之,只要材料够「纯净」,几百米厚的玻璃板也可以看穿。这一重要先见开创了光通讯的领域。这一重要先见开创了光通讯的领域。

论文同时也考虑了很多其他问题:


1.选取适当模式,使绝大部分能量集中在光纤外部,损耗可以进一步降低。

2.光纤外围应为折射率较低的包层(这后来成为标准技术)。
3.光纤弯曲带来的能量损耗在弯曲半径大于1㎜时可以忽略。
4.估计了横截面不均匀带来的损耗。
5.分析了单模光纤的特性。(单模光纤现在成为长距离、大容量数据传输的关键技术。)解释了色散是如何限制带宽的;并且举出了一个10㎞传输的例子,这在1966年是一个非常大胆的例子。

引用该论文总结部分的表述:引用该论文总结部分的表述:

「目前,要成功利用光纤波导,取决于是否能制造出合适的低损耗电介质材料,而其中材料问题是关键的,虽然看似很难,但并非完全没有办法解决。可以肯定的是,所需要达到的20dB/㎞的损耗目标,比基本机制所限定的最低损耗要高出很多。」 「目前,要成功利用光纤波导,取决于是否能制造出合适的低损耗电介质材料,而其中材料问题是关键的,虽然看似很难,但并非完全没有办法解决。可以肯定的是,所需要达到的20dB/㎞的损耗目标,比基本机制所限定的最低损耗要高出很多。」

基本上所有这些预测都准确地指出了发展的路径,现在的技术与当时的预测相比,损耗只是百分之一,而带宽却是万倍。基本上所有这些预测都准确地指出了发展的路径,现在的技术与当时的预测相比,损耗只是百分之一,而带宽却是万倍。现在看来,1966年这篇论文中的革命性建议还是过分保守了。现在看来,1966年这篇论文中的革命性建议还是过分保守了。

藤椅
tt_winner 发表于 2009-12-11 01:58:32
使世界信服

高锟于1966年2月的一次IEE会议上阐述了这篇论文的主旨,但却没有引起世界太多的关注──除了英国邮政局(BPO)和英国国防部(UK Ministry of Defense)外,他们为此立即开展重点研究项目。高锟于1966年2月的一次IEE会议上阐述了这篇论文的主旨,但却没有引起世界太多的关注──除了英国邮政局(BPO)和英国国防部(UK Ministry of Defense)外,他们为此立即开展重点研究项目。到了1966年底,英国有三个研究团队在进行相关主题的研究:标准实验室的高锟本人、英国邮政局的Roberts及Gambling与国防部实验室(Ministry of Defense Laboratory)的Williams的合作队伍。到了1966年底,英国有三个研究团队在进行相关主题的研究:标准实验室的高锟本人、英国邮政局的Roberts及Gambling与国防部实验室(Ministry of Defense Laboratory)的Williams的合作队伍。

在接下来的几年间,高锟到世界各地推广他的构想,足迹所及之处包括;日本(自此建立了不少持久的友谊)、德国的研究实验室,和荷兰等地。在接下来的几年间,高锟到世界各地推广他的构想,足迹所及之处包括;日本(自此建立了不少持久的友谊)、德国的研究实验室,和荷兰等地。他说如果没有更多人加入,玻璃光纤的应用将不会有所发展。他说如果没有更多人加入,玻璃光纤的应用将不会有所发展。面对多方的质疑和批评,他有着非同寻常的坚定信念。面对多方的质疑和批评,他有着非同寻常的坚定信念。全球的电信业非常庞大,非个人或什至单一国家可以改变;但是,他是坚定的,他的热情是如此富有感染力,渐渐地他改变了其他人,令他们相信他的构想。全球的电信业非常庞大,非个人或什至单一国家可以改变;但是,他是坚定的,他的热情是如此富有感染力,渐渐地他改变了其他人,令他们相信他的构想。

起初,专家们宣称,根本上不可逾越的问题中,材料是最严重的一个。起初,专家们宣称,根本上不可逾越的问题中,材料是最严重的一个。 Gambling提到British Telecom早先对这个提议的态度是「有些尖刻」的。 Gambling提到British Telecom早先对这个提议的态度是「有些尖刻」的。而本可轻易尽占先机的贝尔实验室,起先也忽视了这项提议,直至他们看到这项提议的可行性。而本可轻易尽占先机的贝尔实验室,起先也忽视了这项提议,直至他们看到这项提议的可行性。高锟寻访了多家玻璃制造商,游说他们制造所需的纯净玻璃。高锟寻访了多家玻璃制造商,游说他们制造所需的纯净玻璃。他从康宁(Corning)得到了回应。他从康宁(Corning)得到了回应。由Maurer带领的康宁团队,第一次生产出玻璃预制棒,并发明了使玻璃光纤合乎规格的技术。由Maurer带领的康宁团队,第一次生产出玻璃预制棒,并发明了使玻璃光纤合乎规格的技术。

与此同时,高锟继续致力证明,玻璃光纤在长距离光学传输系统中作为介体的可行性。与此同时,高锟继续致力证明,玻璃光纤在长距离光学传输系统中作为介体的可行性。他们面对一系列难以克服的困难,首先是对低损耗样品的测量技术,而能够获得的样品的长度只有20厘米左右。他们面对一系列难以克服的困难,首先是对低损耗样品的测量技术,而能够获得的样品的长度只有20厘米左右。确保样品表面完美无缺也是非常的困难,还有打磨过程中引起的端面反射损耗。确保样品表面完美无缺也是非常的困难,还有打磨过程中引起的端面反射损耗。在测量过程中他们面临的困境,是要求检测两个样本之间少于0.1%的损耗差别,而整段20厘米长的样本总衰减也只有0.1%,不够精确的测量是毫无意义的。在测量过程中他们面临的困境,是要求检测两个样本之间少于0.1%的损耗差别,而整段20厘米长的样本总衰减也只有0.1%,不够精确的测量是毫无意义的。

1968和1969年间,高博士和他在标准实验室的同事Davies、Jones和Wright,针对上述在玻璃样本内的亮度衰减的测量问题发表了一系列论文。 1968和1969年间,高博士和他在标准实验室的同事Davies、Jones和Wright,针对上述在玻璃样本内的亮度衰减的测量问题发表了一系列论文。在当时,名为分光光度计的测量仪器的灵敏度非常有限──只有43dB/㎞左右。在当时,名为分光光度计的测量仪器的灵敏度非常有限──只有43dB/㎞左右。测量工作非常困难:即使污染极微,也会造成与衰减相若的损耗,而端面效应更易糟糕上十倍。测量工作非常困难:即使污染极微,也会造成与衰减相若的损耗,而端面效应更易糟糕上十倍。高博士和他的团队自制了一个单光束分光光度计,其灵敏度达到21.7dB/㎞。高博士和他的团队自制了一个单光束分光光度计,其灵敏度达到21.7dB/㎞。而后来的双光束分光光度计,更是将灵敏度提高到4.3dB/㎞。而后来的双光束分光光度计,更是将灵敏度提高到4.3dB/㎞。

反射效应是用自制的椭圆率计测量的。反射效应是用自制的椭圆率计测量的。为了制造椭圆率计,他们使用等离子沉积法制造石英样本,制造过程中的高温蒸发了石英中的杂质离子。为了制造椭圆率计,他们使用等离子沉积法制造石英样本,制造过程中的高温蒸发了石英中的杂质离子。利用灵敏的仪器,他们测量了一些玻璃样品的衰减,赫然发现Schott Glass公司的一种红外矽样品,在0.85微米左右的频率范围的衰减只有5dB/㎞!利用灵敏的仪器,他们测量了一些玻璃样品的衰减,赫然发现Schott Glass公司的一种红外矽样品,在0.85微米左右的频率范围的衰减只有5dB/㎞!这最终证明了去除杂质可以将吸收损耗降低到可用的程度。这最终证明了去除杂质可以将吸收损耗降低到可用的程度。

这是非常振奋人心的消息,因为低损耗区域正好落在镓砷激光器的发射光谱带中。这是非常振奋人心的消息,因为低损耗区域正好落在镓砷激光器的发射光谱带中。测量结果明确指出了光纤通信的路向──小体积的镓砷半导体激光器作为光源,低成本的包层玻璃光纤作为传输介体,矽或锗半导体作为检测器。测量结果明确指出了光纤通信的路向──小体积的镓砷半导体激光器作为光源,低成本的包层玻璃光纤作为传输介体,矽或锗半导体作为检测器。梦想不再遥远,这些测量结果明显引起了研究界的兴趣,研发第一个低损耗玻璃光纤波导的竞赛开始了。梦想不再遥远,这些测量结果明显引起了研究界的兴趣,研发第一个低损耗玻璃光纤波导的竞赛开始了。

1967年,Maurer在康宁的化学家同事Schultz净化了玻璃。 1967年,Maurer在康宁的化学家同事Schultz净化了玻璃。 1968年,他的同事Keck和Zimar拉出了光纤。 1968年,他的同事Keck和Zimar拉出了光纤。 1970年,通过外部气相沉积法(OVD),康宁使用掺钛纤芯和矽包层,制造出在0.633微米处损耗为17dB/km的光纤波导。 1970年,通过外部气相沉积法(OVD),康宁使用掺钛纤芯和矽包层,制造出在0.633微米处损耗为17dB/km的光纤波导。两年之后,他们以掺锗纤芯代替掺钛纤芯,制造出一条损耗低至4dB/km的多模光纤。两年之后,他们以掺锗纤芯代替掺钛纤芯,制造出一条损耗低至4dB/km的多模光纤。

在迟疑不决多年之后,贝尔实验室最终于1969年加入行列,创立了光纤研究项目。在迟疑不决多年之后,贝尔实验室最终于1969年加入行列,创立了光纤研究项目。 1972年,他们终于停止了在空心光波导管上的研究,他们的毫米波研究项目亦在1975年终止。 1972年,他们终于停止了在空心光波导管上的研究,他们的毫米波研究项目亦在1975年终止。

正是在这段他经常远行出差的时期,这个卡通笑话在家中流行:正是在这段他经常远行出差的时期,这个卡通笑话在家中流行:

「孩子们,今早你们在餐桌上见到的那个男人就是你们的父亲!」 「孩子们,今早你们在餐桌上见到的那个男人就是你们的父亲!」

我们见他没几天,他又会离开一阵子。我们见他没几天,他又会离开一阵子。有时他会坐飞机去参加当天在纽约ITT总部举行的会议。有时他会坐飞机去参加当天在纽约ITT总部举行的会议。我会忘记他并没有回办公室,还会打电话请他的秘书提醒他回家路上顺路买些牛奶等杂物,他的秘书会这样回答:我会忘记他并没有回办公室,还会打电话请他的秘书提醒他回家路上顺路买些牛奶等杂物,他的秘书会这样回答:

「高太太,您不知道您丈夫今天在纽约吗?」 「高太太,您不知道您丈夫今天在纽约吗?」

对世界的影响对世界的影响

自1976年第一代45Mb/s光纤通信系统建成以来,单根光纤的传输容量已经增长到原来的一百万倍,达到几十Tb/s。自1976年第一代45Mb/s光纤通信系统建成以来,单根光纤的传输容量已经增长到原来的一百万倍,达到几十Tb/s。与此同时,光纤放大器和波分复用技术的发明,使数据得以在百万公里计的光纤中传输。与此同时,光纤放大器和波分复用技术的发明,使数据得以在百万公里计的光纤中传输。这就是光纤通信产业不断发展的历程。这就是光纤通信产业不断发展的历程。

光纤通信已经完全改变了世界。光纤通信已经完全改变了世界。整个电信系统迎来了翻天覆地的变化,国际长途电话变得非常便宜。

全新的大型光纤光学产业,包括光缆制造和设备、光器件、网络系统和设备如雨后春笋般出现。全新的大型光纤光学产业,包括光缆制造和设备、光器件、网络系统和设备如雨后春笋般出现。

亿万公里长的玻璃光纤光缆铺设在地下和海底,构建了一个错综复杂的连接网络,而这个网络正是互联网世界得以存在和发展的基础。亿万公里长的玻璃光纤光缆铺设在地下和海底,构建了一个错综复杂的连接网络,而这个网络正是互联网世界得以存在和发展的基础。

现在的互联网比以前的电话更加普及。现在的互联网比以前的电话更加普及。我们可以上网浏览网页、打电话、写博客、观看视屏、购物、交友。我们可以上网浏览网页、打电话、写博客、观看视屏、购物、交友。没有光纤,上世纪90年代开始的信息技术革命便不可能发生。没有光纤,上世纪90年代开始的信息技术革命便不可能发生。

从过去的几年开始,光纤逐渐以各种方式进入家庭。从过去的几年开始,光纤逐渐以各种方式进入家庭。更加环保的全光网络正在筹划发展当中,光纤通信的革命还没有结束,更可能正刚刚开始。更加环保的全光网络正在筹划发展当中,光纤通信的革命还没有结束,更可能正刚刚开始。

结束语

以光纤为本的全球通讯网络确实做到天涯若比邻,令人与人之间关系更密切,我亦没有必要引用技术数据来证明这一点。以光纤为本的全球通讯网络确实做到天涯若比邻,令人与人之间关系更密切,我亦没有必要引用技术数据来证明这一点。我们得知获得诺贝尔奖的消息,是在加利福尼亚州的凌晨3时,来自斯德哥尔摩(他们的早晨)的电话,无疑是通过光纤传输的;几分钟后,来自亚洲朋友(他们的傍晚)的祝贺信息,也是通过光纤传输。我们得知获得诺贝尔奖的消息,是在加利福尼亚州的凌晨3时,来自斯德哥尔摩(他们的早晨)的电话,无疑是通过光纤传输的;几分钟后,来自亚洲朋友(他们的傍晚)的祝贺信息,也是通过光纤传输。然而信息泛滥并不是一件好事:那晚我们不得不摘掉电话以求安睡。然而信息泛滥并不是一件好事:那晚我们不得不摘掉电话以求安睡。

到目前为止,光纤通信不仅仅是科技上的进步,还为社会带来了显著变革。到目前为止,光纤通信不仅仅是科技上的进步,还为社会带来了显着变革。下一代人将会以不同的方式学习和成长;人们打交道的方式也将有所不同。下一代人将会以不同的方式学习和成长;人们打交道的方式也将有所不同。一件产品各个部分的生产,好有可能分散在世界多个地方,为人们尤其是发展中国家的人民提供了巨大的机遇。一件产品各个部分的生产,好有可能分散在世界多个地方,为人们尤其是发展中国家的人民提供了巨大的机遇。信息的广泛传播,明显带来更多平等和参与公共事务的机会。信息的广泛传播,明显带来更多平等和参与公共事务的机会。

已经有很多人谈过和写过信息社会,我不打算多谈──我只想说这一切已经远远超过了1966年第一次正式提出光通讯概念时的梦想,在那时,即使是1GHz ,都只是一种美好的愿望而已。已经有很多人谈过和写过信息社会,我不打算多谈──我只想说这一切已经远远超过了1966年第一次正式提出光通讯概念时的梦想,在那时,即使是1GHz ,都只是一种美好的愿望而已。

板凳
tt_winner 发表于 2009-12-11 01:59:00
最后,高锟教授和我想感谢香港中文大学的教授,他们是:杨教授、黄教授、张教授和陈教授,在准备这篇演讲稿时他们给予了我们莫大帮助。最后,高锟教授和我想感谢香港中文大学的教授,他们是:杨教授、黄教授、张教授和陈教授,在准备这篇演讲稿时他们给予了我们莫大帮助。高锟也感谢ITT公司,在那里他用了30年的时间发展出自己的事业,同时感谢早期和他一同投入光纤研发的同事。高锟也感谢ITT公司,在那里他用了30年的时间发展出自己的事业,同时感谢早期和他一同投入光纤研发的同事。没有一大群志同道合的人,这个工业便不会蓬勃发展至今天这个面貌。没有一大群志同道合的人,这个工业便不会蓬勃发展至今天这个面貌。

高锟埋下了这颗种子,Bob Maurer为它浇水,同时,John MacChesney使它生根茁壮

报纸
tt_winner 发表于 2009-12-11 02:01:22
Sand from centuries past;Send future voices fast.

A Nobel Lecture organized by the Royal Swedish Academy of Sciences
and The Prize Committee in Physics delivered by Mrs Gwen MW Kao
on behalf of Prof Charles K Kao Nobel Laureate in Physics 2009
8 December 2009 Aula Magna Stockholm University

1. Introduction
It is sad that my husband, Professor Charles Kao, is unable to give this lecture to you himself. As the person closest to him, I stand before you to honour him and to speak for him. He is very very proud of his achievements for which the Nobel Foundation honours him. As are we all!
In the 43 years since his seminal paper of 1966 that gave birth to the ubiquitous glass fiber cables of today, the world of telephony has changed vastly. It is due to Professor Kao’s persistence in the face of skepticism that this revolution has occurred.
In the 1970s the pre-production stage moved to ITT Corp Roanoke VA, USA. Whilst Charles worked there, he received two letters. One contained a threatening message accusing him of releasing an evil genie from its bottle; the other, from a farmer in China, asked for a means to allow him to pass a message to his distant wife to bring his lunch. Both letter writers saw a future that has since become past history.

In the 1960s, our children were small. Charles often came home later than normal – dinner was waiting as were the children. I got very annoyed when this happened day after day. His words,maybe not exactly remembered, were –‘Please don’t be so mad. It is very exciting what we are doing; it will shake the world one day!’ I was sarcastic, ‘Really, so you will get the Nobel Prize, won’t you!
He was right – it has revolutionized telecommunications.

2. The early days
In 1960, Charles joined Standard Telecommunications Laboratories Ltd. (STL), a subsidiary of ITT Corp in the UK, after having worked as a graduate engineer at Standard Telephones and Cables in Woolwich for some time. Much of the work at STL was devoted to improving the capabilities of the existing communication infrastructure with a focus on the use of millimeter wave transmission systems.
Millimeter waves at 35 to 70 GHz could have a much higher transmission capacity. But the waters were uncharted and the challenges enormous, since radio waves at such frequencies could not be beamed over long distances due to beam divergence and atmospheric absorption. The waves had to be guided by a waveguide. And in the 1950’s, R&D work on low loss circular waveguides –HE-11 mode – was started. A trial system was deployed in the 1960s. Huge sums were invested, and more were planned, to move this system into the pre-production stage. Public expectation for new telecommunication services such as the video phone had heightened.

Charles joined the long-haul waveguide group led by Dr Karbowiak at STL. He was excited to see an actual circular waveguide. He was assigned to look for new transmission methods for microwave and optical transmission. He used both ray optics and wave theory to gain a better understanding of waveguide problems – then a novel idea. Later, his boss encouraged him to pursue a doctorate while working at STL. So Charles registered at University College London and completed the dissertation ‘Quasi-Optical Waveguides’ in two years.

The invention of the laser in 1959 gave the telecom community a great dose of optimism that optical communication could be just around the corner. The coherent light was to be the new information carrier with capacity a hundred thousand times higher than point-to-point microwaves –based on the simple comparison of frequencies: 300 terahertz for light versus 3 gigahertz for microwaves.
The race between circular microwave waveguides and optical communication was on, with the odds heavily in favour of the former. In 1960, optical lasers were in their infancy, demonstrated at only a few research laboratories, and performing much below the needed specs. Optical systems seemed a non-starter.

But Charles still thought the laser had potential. He said to himself: ‘How can we dismiss the laser so readily? Optical communication is too good to be left on the theoretical shelf.’

He asked himself the obvious questions:
1. Is the ruby laser a suitable source for optical communication?
2. What material has sufficiently high transparency at such wavelengths?
At that time only two groups in the world were starting to look at the transmission aspect of optical communication, while several other groups were working on solid state and semiconductor lasers. Lasers emit coherent radiation at optical frequencies, but using such radiation for communication appeared to be very difficult, if not impossible. For optical communication to fulfill its promises, many serious problems remained to be solved.

地板
kczhou23 发表于 2009-12-11 02:01:35
一个字——长。。。

7
tt_winner 发表于 2009-12-11 02:01:43
3. The key discovery
In 1963 Charles was already involved in free space propagation experiments: the rapid progress of semiconductor and laser technology had opened up a broader scope to explore optical communication realistically. With a helium-neon laser beam directed to a spot some distance away, the STL team quickly discovered that distant laser light flickered. The beam danced around several beam diameters because of atmospheric fluctuations.
The team also tried to repeat experiments done by other research laboratories around the world. For example, they set up con-focal lens experiments similar to those at Bell Labs: a series of convex lenses were lined up at intervals equal to the focal length. But even at the dead of night when the air was still and even with refocusing every 100 meters, the beam refused to stay within the lens aperture.
Bell Labs experiments using gas lenses were abandoned due to the difficulty of providing satisfactory insulation while maintaining the profiles of the gas lenses. These experiments were struggles in desperation, to control light travelling over long distances.
At STL the thinking shifted towards dielectric waveguides. Dielectric means a non-conductor of electricity; a dielectric waveguide is a waveguide consisting of a dielectric cylinder surrounded by air. Dr Karbowiak suggested Charles and three others to work on his idea of a thin film waveguide.
But thin film waveguides failed: the confinement was not strong enough and light would escape as it negotiates a bend.
When Dr Karbowiak decided to emigrate to Australia, Charles took over as the project leader and he then recommended that the team should investigate the loss mechanism of dielectric materials for optical fibers.
A small group worked on methods for measuring material loss of low-loss transparent materials. George Hockham joined him to work on the characteristics of dielectric waveguides.
With his interest in waveguide theory, he focused on the tolerance requirements for an optical fiber waveguide; in particular, the dimensional tolerance and joint losses. They proceeded to systematically study the physical and waveguide requirements on glass fibers.
In addition, Charles was also pushing his colleagues in the laser group to work towards a semiconductor laser in the near infrared, with emission characteristics matching the diameter of a single-mode fiber. Single mode fiber is optical fiber that is designed for the transmission of a single ray or mode of light as a carrier. The laser had to be made durable, and to work at room temperatures without liquid nitrogen cooling. So there were many obstacles. But in the early 1960s,
esoteric research was tolerated so long as it was not too costly.
Over the next two years, the team worked towards the goals. They were all novices in the physics and chemistry of materials and in tackling new electromagnetic wave problems. But they made very credible progress in considered steps. They searched the literature, talked to experts, and collected material samples from various glass and polymer companies. They also worked on the theories, and developed measurement techniques to carry out a host of experiments. They developed an instrument to measure the spectral loss of very low-loss material, as well as one for scaled simulation experiments to measure fiber loss due to mechanical imperfections.
Charles zeroed in on glass as a possible transparent material. Glass is made from silica –sand from centuries past that is plentiful and cheap.
The optical loss of transparent material is due to three mechanisms: (a) intrinsic absorption, (b)extrinsic absorption, and (c) Rayleigh scattering. The intrinsic loss is caused by the infrared absorption of the material structure itself, which determines the wavelength of the transparency
regions. The extrinsic loss is due to impurity ions left in the material and the Rayleigh loss is due to the scattering of photons by the structural non-uniformity of the material. For most practical applications such as windows, the transparency of glass was entirely adequate, and no one had studied absorption down to such levels. After talking with many people, Charles eventually formed the following conclusions.

1. Impurities, particularly transition elements such as iron, copper, and manganese, have to be reduced to parts per million or even parts per billion. However, can impurity concentrations be reduced to such low levels?
2. High temperature glasses are frozen rapidly and therefore are more homogeneous, leading to a lower scattering loss.
The ongoing microwave simulation experiments were also completed. The characteristics of the dielectric waveguide were fully defined in terms of its modes, its dimensional tolerance both for end-to-end mismatch and for its diameter fluctuation along the fiber lengths. Both the theory and the simulated experiments supported the approach.
They wrote the paper entitled, ‘Dielectric-Fibre Surface Waveguides for Optical Frequencies’ and submitted it to the Proceedings of Institute of Electrical Engineers. After the usual review and revision, it appeared in July 1966 – the date now regarded as the birthday of optical fiber communication.
4. The paper
The paper started with a brief discussion of the mode properties in a fiber of circular cross section.
The paper then quickly zeroed in on the material aspects, which were recognized to be the major stumbling block. At the time, the most transparent glass had a loss of 200 dB/km, which would limit transmission to about a few meters – this is very obvious to anyone who has ever peered through a thick piece of glass. Nothing can be seen.
But the paper pointed out that the intrinsic loss due to scattering could be as low as 1 dB/km,which would have allowed propagation over practical distances. The culprit is the impurities:
mainly ferrous and ferric ions at these wavelengths. Quoting from the paper: ‘It is foreseeable that glasses with a bulk loss of about 20 dB/km at around 0.6 micron will be obtained, as the iron-impurity concentration may be reduced to 1 part per million’. In layman terms, if one has a sufficiently ‘clean’ type of glass, one should be able to see through a slab as thick as several hundred meters. That key insight opened up the field of optical communications.

The paper considered many other issues:
? The loss can be reduced if the mode is chosen so that most of the energy is actually outside the fiber.
? The fiber should be surrounded by a cladding of lower index (which became the standard technology).
? The loss of energy due to bends in the fiber is negligible for bends larger than 1 mm.
? The losses due to non-uniform cross sections were estimated.
? The properties of a single-mode fiber (now a key technology especially for long distance and high data rate transmission) were analyzed. It was explained how dispersion limits bandwidth; an example was worked out for a 10 km route – a very bold scenario in 1966.

It may be appropriate to quote from the Conclusion of this paper:
The realization of a successful fiber waveguide depends, at present, on the availability of suitable low-loss dielectric material. The crucial material problem appears to be one which is difficult but not
impossible to solve. Certainly, the required loss figure of around 20 dB/km is much higher than the lower limit of loss figure imposed by fundamental mechanisms.

Basically all of the predictions pointed accurately to the paths of developments, and we now have 1/100 of the loss and 10,000 times the bandwidth then forecast – the evolutionary proposal in the 1966 paper was in hindsight too conservative.

8
tt_winner 发表于 2009-12-11 02:02:10
5. Convincing the world
The substance of the paper was presented by Dr Kao at an IEE meeting in February 1966. Most of the world did not take notice – except for the British Post Office (BPO) and the UK Ministry of Defense, who immediately launched major research programs. By the end of 1966, three groups in the UK were studying the various issues involved: Kao himself at STL; Roberts at BPO; Gambling at Southampton in collaboration with Williams at the Ministry of Defense Laboratory.
In the next few years, Dr Kao traveled the globe to push his idea: to Japan, where enduring friendships were made dating from those early days; to research labs in Germany, in the Netherlands and elsewhere to spread his news. He said that until more and more jumped on the bandwagon, the use of glass fibers would not take off. He had tremendous conviction in the face of widespread skepticism. The global telephony industry is huge, too large to be changed by a single person or even a single country, but he was persistent and his enthusiasm was contagious, and slowly he converted others to be believers.
The experts at first proclaimed that the materials were the most severe of the intrinsic insurmountable problems. Gambling wrote that British Telecom had been ‘somewhat scathing’about the proposal earlier, and Bell Labs, who could easily have led the field, simply failed to take notice until the proven technology was pointed out to them. Dr Kao visited many glass manufacturers to persuade them to produce the clear glass required. He got a response from Corning, where Maurer led the first group that later produced the glass rods and developed the
techniques to make the glass fibers to the required specifications.
Meanwhile, Dr Kao continued to pour energy into proving the feasibility of glass fibers as the medium for long-haul optical transmission. They faced a number of formidable challenges. The first was the measurement techniques for low-loss samples that were obtainable only in lengths of around 20 cm. The problem of assuring surface perfection was also ormidable. Another problem is end surface reflection loss, caused by the polishing process. They faced a measurement impasse that demanded the detection of a loss difference between two samples of less than 0.1%, when the total loss of the entire 20 cm sample is only 0.1%. An inexact measurement would be meaningless.
In 1968 and 1969, Dr Kao and his colleagues Davies, Jones and Wright at STL published a series of papers on the attenuation measurements of glass that addressed the above problems. At that time, the measuring instruments called spectrophotometers had a rather limited sensitivity – in the range of 43 dB/km. The measurement was very difficult: even a minute contamination could have caused a loss comparable to the attenuation itself, while surface effects could easily be ten times worse. Dr Kao and the team assembled a homemade single-beam spectrophotometer that achieved a sensitivity of 21.7 dB/km. Later improvements with a double-beam spectrophotometer yielded a sensitivity down to 4.3 dB/km.
The reflection effect was measured with a homemade ellipsometer. To make it, they used fused quartz samples made by plasma deposition, in which the high temperature evaporated the impurity ions. With the sensitive instrument, the attenuation of a number of glass samples was measured and, eureka, the Infrasil sample from Schott Glass showed an attenuation as low as 5 dB/km at a window around 0.85 micron – at last proving that the removal of impurity would lower the absorption loss to useful levels.
This was really exciting because the low-loss region is right at the gallium-arsenide laser emission band. The measurements clearly pointed the way to optical communication –compact gallium-arsenide semiconductor lasers as the source, low-cost cladded glass fibers as the transmission medium, and silicon or germanium semiconductors for detection. The dream no longer seemed remote. These measurements apparently turned the sentiments of the research community around. The race to develop the first low-loss glass fiber waveguide was on.

In 1967, at Corning, Maurer’s chemist colleague Schultz helped to purify the glass.
In 1968, his colleagues Keck and Zimar helped to draw the fibers. By 1970, Corning had produced a fiber waveguide with a loss of 17 dB/km at 0.633 micron using a titanium-diffused core with silica cladding, using the Outside Vapor Deposition (OVD) method. Two years later, they reduced the loss to 4 dB/km for a multimode fiber by replacing the titanium-doped core with a germanium-doped core.
Bell Labs finally got on the bandwagon in 1969 and created a programme in optical fiber research after having been skeptical for years. Their work on hollow light pipes was finally stopped in 1972. Their millimeter wave research programme was wound down and eventually abandoned in 1975.
It was during this time of constant flying out to other places that this cartoon joke hit home:‘Children, the man you see at the breakfast table today is your father!’
We saw him for a few days and off he went again. Sometimes he flew off for the day for meetings at ITT Corp headquarters in New York. I would forget he had not left to go to the office and would phone his secretary to remind Charles to pick up milk or something on his way home.

His secretary was very amused:‘Mrs Kao, don’t you know your husband is in New York today!’

6. Impact on the world
Since the deployment of the first-generation, 45-megabit-per-second fiber-optic communication system in 1976, the transmission capacity in a single fiber has rapidly increased a million fold to tens of terabits per second. Data can be carried over millions of km of fibers without going through repeaters, thanks to the invention of the optical fiber amplifier and wavelength division multiplexing. So that is how the industry grew and grew. The world has been totally transformed because of optical fiber communication. The telephone system has been overhauled and international long distance calls have become easily affordable.
Brand new mega-industries in fiber optics including cable manufacturing and equipment, optical devices, network system and equipment have been created.
Hundreds of millions of kilometers of glass fiber cables have been laid, in the ground and in the ocean, creating an intricate web of connectivity that is the foundation of the world-wide web.
The Internet is now more pervasive than the telephone used to be. We browse, we skype, we blog, we go onto you-tube, we shop, we socialize on-line. The information revolution that started in the 1990s could not have happened without optical fibers.

Over the last few years fibers are being laid all the way to our homes. All-optical networks that are environmentally green are contemplated. The revolution in optical fiber communication has not ended – it might still just be at the beginning.

7. Conclusion
The world-wide communication network based on optical fibers has truly shrunk the world and brought human beings closer together. I hardly need to cite technical figures to drive this point home. The news of the Nobel Prize reached us in the middle of the night at 3 am in California, through a telephone call from Stockholm (then in their morning) no doubt carried on optical fibers; congratulations came literally minutes later from friends in Asia (for whom it was evening), again through messages carried on optical fibers. Too much information is not always a good thing: we had to take the phone off the hook that night in order to get some sleep!
Optical communication is by now not just a technical advance, but has also caused major changes in society. The next generation will learn and grow up differently; people will relate to one another in different ways. Manufacturing of all the bits and pieces of a single product can now take place over a dozen locations around the world, providing huge opportunities for people especially in developing countries. The wide accessibility of information has obviously led to more equality and wider participation in public affairs.
Many words, indeed many books have been written about the information society, and I do not wish to add to them here – except to say that it is beyond the dreams of the first serious concept of optical communication in 1966, when even 1 GHz was only a hope.
In conclusion, Charles and I want to thank the Professors at The Chinese University of Hong Kong, namely: Professor Young, Professor Wong, Professor Cheung and Professor Chen for their support in compiling this lecture for us. Charles would like to thank ITT Corp where he developed his career for 30 years and all those who climbed on to the bandwagon with him in the early days, as without the legions of believers the industry would not have evolved as it did.
Charles Kao planted the seed; Bob Maurer watered it and John MacChesney grew its roots.

9
tt_winner 发表于 2009-12-11 11:15:08
大家都看看啊

10
xylina1001 发表于 2010-1-7 23:39:35
有些小问题啊 楼主能否编辑一下
分享是一种享受;交流是一种进步

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