Nzira yekudzikisa sei ruzha rwemafotodetectors

Nzira yekudzikisa sei ruzha rwemafotodetectors

Ruzha rwemafotodetectors rinonyanya kusanganisira: ruzha rwemazuva ano, ruzha rwekupisa, ruzha rwepfuti, 1/f ruzha uye ruzha rwakakura, nezvimwewo. Panguva ino, isu tichaunza yakadzama hunhu hweruzha uye kupatsanura kubatsira munhu wese kuti anzwisise zvirinani maitiro emhando dzakasiyana dzeruzha pane zvinobuda masaini emafotodetectors. Chete nekunzwisisa kwainobva ruzha tinogona kudzikisa zvirinani nekuvandudza ruzha rwemafotodetectors, nekudaro tichigonesa chiratidzo-ku-ruzha reshiyo yehurongwa.

Shot noise is a random fluctuation inokonzerwa ne discrete nature yevanochaja vatakuri. Kunyanya mukuita kwephotoelectric, kana mafotoni akarova photosensitive zvikamu kugadzira maerekitironi, kugadzirwa kwemaerekitironi aya kunongoitika uye kunoenderana nekugoverwa kwePoisson. Iwo maspectral maitiro eruzha rwepfuti akati sandara uye akazvimirira pa frequency magnitude, uye nekudaro inodaidzwa zvakare kuti chena ruzha. Tsanangudzo yemasvomhu: Mudzi unoreva square (RMS) kukosha kweruzha rwepfuti inogona kuratidzwa se:

Pakati pavo:

e: Electronic charge (inenge 1.6 × 10-19 coulombs)

Idark: Rima ikozvino

Δf: Bandwidth

Shot noise inoenderana nehukuru hweizvino uye inogadzikana pama frequency ese. Mune fomula, Idark inomiririra yakasviba yazvino yephotodiode. Ndiko kuti, mukushayikwa kwechiedza, iyo photodiode ine isingadiwi yakasviba ruzha ruzha. Sezvo ruzha rwemukati kumucheto kwepamberi kwefotodetector, iyo yakakura yakasviba ikozvino, iyo yakakura ruzha rwephotodetector. Rima razvino rinokanganiswawo neiyo bias inoshanda voltage yephotodiode, ndiko kuti, iyo yakakura iyo bias inoshanda voltage, iyo yakakura yakasviba ikozvino. Nekudaro, iyo bias inoshanda voltage inokanganisawo junction capacitance yephotodetector, nekudaro ichipesvedzera kumhanya uye bandwidth yephotodetector. Uyezve, iyo yakakura iyo bias voltage, iyo yakakura kumhanya uye bandwidth. Naizvozvo, maererano neruzha rwepfuti, yakasviba ikozvino uye bandwidth mashandiro ephotodiodes, dhizaini inonzwisisika inofanira kuitwa zvinoenderana nezvinodiwa chaizvo zveprojekiti.

2. 1/f Flicker Noise

1/f ruzha, inozivikanwawo seflicker noise, inowanzoitika munzvimbo yakaderera-frequency uye ine chekuita nezvinhu zvakaita sehurema hwezvinhu kana kuchena kwepasi. Kubva pane iyo spectral characteristic diagram, inogona kuonekwa kuti simba rayo spectral density idiki zvakanyanya mu-high-frequency range pane ye-low-frequency range, uye kune imwe neimwe ka100 inowedzera muhuwandu, spectral density ruzha runoderera nekagumi. Iyo simba spectral density ye1/f ruzha inopesana neiyo frequency, kureva:

Pakati pavo:

SI (f): Noise simba spectral density

Ini: Iyezvino

f: kakawanda

1/f ruzha rwakakosha mune yakaderera-frequency renji uye inopera simba sezvo frequency inowedzera. Hunhu uhu hunoita kuti ive sosi huru yekuvhiringidza mune yakaderera-frequency application. 1/f ruzha uye ruzha rwebandband rinonyanya kubva kune ruzha rwevoltage yeanoshanda amplifier mukati meiyo photodetector. Kune mamwe akawanda masosi eruzha anokanganisa ruzha rwemafotodetectors, senge simba rekupa ruzha rweanoshanda amplifiers, ruzha rwazvino, uye ruzha rwekupisa rwekupokana network mukuwana kweanoshanda amplifier maseketi.

3. Voltage uye ruzha rwemazuva ano rwechigadziriso chekushanda: Iyo voltage uye ikozvino spectral densities inoratidzwa mumufananidzo unotevera:

Mukushanda amplifier maseketi, ruzha rwazvino rwakakamurwa kuita mu-chikamu chazvino ruzha uye inverting yazvino ruzha. Iyo in-phase yazvino ruzha i+ inoyerera kuburikidza nekwakabva mukati mekudzivirira maRs, ichigadzira yakaenzana voltage ruzha u1 = i+* Rs. I-Inverting ikozvino ruzha runoyerera kuburikidza nekuwana yakaenzana resistor R kuti ibudise yakaenzana voltage noise u2 = I-* R. Saka kana RS yemagetsi emagetsi yakakura, ruzha rwemagetsi rwakashandurwa kubva kune ruzha rwemazuva ano rwakakurawo zvikuru. Naizvozvo, kukwidziridza ruzha rwuri nani, iyo magetsi ekupa ruzha (kusanganisira yemukati kuramba) zvakare igwara rakakosha rekugadzirisa. Iyo spectral density yeazvino ruzha haishanduke nekusiyana kwema frequency kana. Naizvozvo, mushure mekukwidziridzwa nedunhu, iyo, senge yakasviba ikozvino yefotodiode, inoumba zvakakwana ruzha rwepfuti rwephotodetector.

4. Ruzha rwekupisa rwekupokana network yekuwana (amplification factor) yeanoshanda amplifier wedunhu inogona kuverengerwa uchishandisa inotevera formula:

Pakati pavo:

k: Boltzmann nguva dzose (1.38 × 10-23J/K)

T: Absolute Temperature (K)

R: Resistance (ohms) ruzha rwekupisa runoenderana nekupisa uye kukosha kwekupokana, uye chimiro chayo chakapfava. Iyo inogona kuoneka kubva kune formula kuti iyo yakakura kuwana kupikisa kukosha, iyo yakakura ruzha rwekupisa. Iyo yakakura iyo bandwidth, iyo yakakura ruzha rwekupisa ichave zvakare. Naizvozvo, kuti ive nechokwadi chekuti kukosha kwekupokana uye kukosha kwebandwidth kunosangana nezvose zvinodiwa kuwana uye bandwidth zvinodiwa, uye pakupedzisira zvakare inoda yakaderera ruzha kana yakakwira chiratidzo-kune-ruzha reshiyo, kusarudzwa kwevanopikisa kuwana kunoda kunyatsotariswa uye kuongororwa zvichibva pane chaiyo purojekiti zvinodiwa kuti uwane iyo yakakodzera chiratidzo-kune-ruzha chiyero chehurongwa.

Summary

Ruzha rwekuvandudza tekinoroji inoita basa rakakosha mukusimudzira mashandiro emafotodetectors uye zvigadzirwa zvemagetsi. High precision inoreva ruzha rushoma. Sezvo tekinoroji ichida kurongeka kwepamusoro, zvinodikanwa zveruzha, chiratidzo-kune-ruzha reshiyo, uye yakaenzana ruzha simba remafotodetectors ari kuwedzera nekukwira.