利用强光源作为激励,测量了Cs_2Te紫外光电阴极带外光谱响应。结果表明Cs_2Te紫外光电阴极的带外光谱响应较低,与带内光谱响应相比相差几个数量级。带内光谱响应的峰值灵敏度可以大于40 m A/W,但对带外光谱响应,如对550 nm的波长,其光...利用强光源作为激励,测量了Cs_2Te紫外光电阴极带外光谱响应。结果表明Cs_2Te紫外光电阴极的带外光谱响应较低,与带内光谱响应相比相差几个数量级。带内光谱响应的峰值灵敏度可以大于40 m A/W,但对带外光谱响应,如对550 nm的波长,其光谱响应可以低至10-3 m A/W数量级。对采用同样工艺所制作的Cs_2Te紫外光电阴极,其带外光谱响应的离散性较大。根据对3种不同可见光阴极,即Na2KSb（Cs）多碱光电阴极、K2Cs Sb双碱光电阴极以及Ga As（Cs-O）光电阴极带外光谱响应的测试,证明这3种可见光阴极均存在不同大小的带外光谱响应。测试数据表明,带外光谱响应与逸出功（正电子亲和势光电阴极）或禁带宽度（负电子亲和势光电阴极）的大小相关。逸出功越低或禁带宽度越小,带外光谱响应越大。根据光电发射的方程,可以推测出Cs_2Te紫外光电阴与上述3种可见光光电阴极一样,产生带外光谱响应的原因是多光子吸收,即多光子效应。由于Cs_2Te紫外光电阴极存在带外光谱响应,因此当采用Cs_2Te紫外光电阴极的“日盲”像增强器在强烈的太阳光下或直对太阳光使用时,会受到太阳光的干扰或看到太阳的像,不具备日盲特性。为了使“日盲”紫外像增强器完全具备日盲特性,需要“日盲”紫外像增强器Cs_2Te紫外阴极前增加“日盲”滤光片,利用“日盲”滤光片消去Cs_2Te紫外阴极的带外光谱响应达到“日盲”的目的。因此在实际应用过程中,“日盲”滤光片是必不可少的。“日盲”滤光片设计的依据是Cs_2Te紫外阴极对太阳辐射的响应度。Cs_2Te紫外阴极对太阳辐射的响应主要集中在350~650 nm之间,因此“日盲”滤光片主要应对该波段的可见光进行衰减。只有使用与Cs_2Te紫外阴极带外光谱响应相匹配的“日盲”滤光片才有可能使“日盲”紫外像增强器具备“日盲”特性。展开更多
This paper addresses the problem of survivable traffic assignment with failure probability requirement in flexible bandwidth optical networks. We describe a Survivable Traffic Cognition (STC) algorithm with joint fail...This paper addresses the problem of survivable traffic assignment with failure probability requirement in flexible bandwidth optical networks. We describe a Survivable Traffic Cognition (STC) algorithm with joint failure probability. Survivable Traffic Assignment (STA) algorithm and Conventional Traffic Assignment (CTA) algorithm are added to illustrate the effectiveness of our proposed STC. We investigate the effect of joint failure probability on blocking probability, spectral utilization ratio, average joint failure probability, and the average hops. Simulation results show that our proposed STC not only achieves better performance in terms of blocking probability and spectral utilization ratio than CTA and STA, but also does not cause higher average joint failure probability or larger average hops compared with STA. As a result, STC makes the best use of spectral resources and does not cause large average joint failure probability.展开更多
文摘利用强光源作为激励,测量了Cs_2Te紫外光电阴极带外光谱响应。结果表明Cs_2Te紫外光电阴极的带外光谱响应较低,与带内光谱响应相比相差几个数量级。带内光谱响应的峰值灵敏度可以大于40 m A/W,但对带外光谱响应,如对550 nm的波长,其光谱响应可以低至10-3 m A/W数量级。对采用同样工艺所制作的Cs_2Te紫外光电阴极,其带外光谱响应的离散性较大。根据对3种不同可见光阴极,即Na2KSb（Cs）多碱光电阴极、K2Cs Sb双碱光电阴极以及Ga As（Cs-O）光电阴极带外光谱响应的测试,证明这3种可见光阴极均存在不同大小的带外光谱响应。测试数据表明,带外光谱响应与逸出功（正电子亲和势光电阴极）或禁带宽度（负电子亲和势光电阴极）的大小相关。逸出功越低或禁带宽度越小,带外光谱响应越大。根据光电发射的方程,可以推测出Cs_2Te紫外光电阴与上述3种可见光光电阴极一样,产生带外光谱响应的原因是多光子吸收,即多光子效应。由于Cs_2Te紫外光电阴极存在带外光谱响应,因此当采用Cs_2Te紫外光电阴极的“日盲”像增强器在强烈的太阳光下或直对太阳光使用时,会受到太阳光的干扰或看到太阳的像,不具备日盲特性。为了使“日盲”紫外像增强器完全具备日盲特性,需要“日盲”紫外像增强器Cs_2Te紫外阴极前增加“日盲”滤光片,利用“日盲”滤光片消去Cs_2Te紫外阴极的带外光谱响应达到“日盲”的目的。因此在实际应用过程中,“日盲”滤光片是必不可少的。“日盲”滤光片设计的依据是Cs_2Te紫外阴极对太阳辐射的响应度。Cs_2Te紫外阴极对太阳辐射的响应主要集中在350~650 nm之间,因此“日盲”滤光片主要应对该波段的可见光进行衰减。只有使用与Cs_2Te紫外阴极带外光谱响应相匹配的“日盲”滤光片才有可能使“日盲”紫外像增强器具备“日盲”特性。
基金supported in part by 973 Program under Grants No. 2010CB328204,No. 2012CB315604863 Program under Grant No. 2012AA011301+3 种基金National Natural Science Foundation of China under Grants No. 61271189,No. 61201154, No. 60932004RFDP Project under Grants No. 20090005110013,No. 20120005120019the Fundamental Research Funds for the Central Universitiesthe State Scholarship Fund
文摘This paper addresses the problem of survivable traffic assignment with failure probability requirement in flexible bandwidth optical networks. We describe a Survivable Traffic Cognition (STC) algorithm with joint failure probability. Survivable Traffic Assignment (STA) algorithm and Conventional Traffic Assignment (CTA) algorithm are added to illustrate the effectiveness of our proposed STC. We investigate the effect of joint failure probability on blocking probability, spectral utilization ratio, average joint failure probability, and the average hops. Simulation results show that our proposed STC not only achieves better performance in terms of blocking probability and spectral utilization ratio than CTA and STA, but also does not cause higher average joint failure probability or larger average hops compared with STA. As a result, STC makes the best use of spectral resources and does not cause large average joint failure probability.
