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1、信息获取技术和材料第1 页，本讲稿共18 页光电探测器按光电转换方式，光电探测器可分为:光电导型、光生伏打型（势垒型）和热电偶型。光电转换中根据探测的光子波长分为:狭能隙半导体材料（红外）和宽能隙半导体材料（可见和紫外）。宽能隙材料以Si、Ge、和GaN、AlN 等为主，狭能隙半导体材料主要为铅盐、碲镉汞、SbIn 等。第2 页，本讲稿共18 页近期光电探测器最大的进展在两个方面：(1)用超晶格（量子阱）结构提高了量子效率、相应时间和集成度；（2）制成了探测器阵，可以用作成像探测。两者结合后最典型的例子为可以制成探测灵敏度极高的HgCdTe 红外焦平面列阵（FPA），并成功地应用于红外遥感、成
2、像等。第3 页，本讲稿共18 页Photodetector:convert light into electricity through the photoelctric effectRequirements:high sensitivity,fast response,low noise,low cost,and high reliability第4 页，本讲稿共18 页R is the responsivity of the photodetector(A/W)第5 页，本讲稿共18 页the bandwidth of a photodetector is determined by th
3、e speed with which it responds to variations in the incident optical power.The rise time Tr is defined as the time over which the current builds up from 10%to 90%of its final value when the incident optical power is changed abruptly.tr is the transit time and RC is the time constant of the equivalen
4、t RC circuit.第6 页，本讲稿共18 页The transit time is added to RC because it takes some time before the carriers are collected after their generation through absorption of photons.The maximum collected time is just equal to the time an electron takes to traverse the absorption region.There is a trade-off be
5、tween the bandwidth and the responsivity(speed versus sensitivity)of photodetector.Often,the RC time constant RC limits the bandwidth because of electrical parasitics.第7 页，本讲稿共18 页These high-speed photodetectors show flat response in both amplitude and phase up to 25 GHz and are optimized for freque
6、ncy-domain applications.The high-sensitivity Model 1414 near-IR photodetectors use 25-m-diameter back-illuminated InGaAs Schottky photodiodes with peak responsivities of 0.6 A/W at 1300 nm.The active layer is twice as thick as in our ultrahigh-speed Model 101X module,producing a 50%greater responsiv
7、ity between 950 nm and 1650 nm.The conversion gain with a 50-W load is 15 V/W.25-GHz Near-IR Photodetector 第8 页，本讲稿共18 页第9 页，本讲稿共18 页U2t XPDV2020R-VF-FP photodetector第10 页，本讲稿共18 页第11 页，本讲稿共18 页第12 页，本讲稿共18 页第13 页，本讲稿共18 页Ultra-high speed optical pulse waveform measurement is Achieved by using the sub-picosecond optical pulse generation technology with a passively mode-locked fiber laser and the nonlinear optical technology with the sum-frequency(SF)light generation.第14 页，本讲稿共18 页第15 页，本讲稿共18 页第16 页，本讲稿共18 页第17 页，本讲稿共18 页第18 页，本讲稿共18 页