Indlela yokunciphisa umsindo we-photodetectors

Indlela yokunciphisa umsindo we-photodetectors

Umsindo wama-photodetector uhlanganisa kakhulu: umsindo wamanje, umsindo wokushisa, umsindo wokudubula, umsindo we-1/f nomsindo we-wideband, njll. Lokhu kuhlukaniswa kungokulinganiselwe. Kulokhu, sizokwethula izici zomsindo ezinemininingwane eminingi kanye nokuhlukaniswa ukuze sisize wonke umuntu aqonde kangcono umthelela wezinhlobo ezahlukene zomsindo ezimpawini zokukhishwa kwama-photodetector. Kungokuqonda imithombo yomsindo kuphela lapho singanciphisa futhi sithuthukise kangcono umsindo wama-photodetector, ngaleyo ndlela senze ngcono isilinganiso sesiginali kuya komsindo sohlelo.

Umsindo wokudubula uwukuguquguquka okungahleliwe okubangelwa uhlobo oluhlukile lwabathwali be-charge. Ikakhulukazi emphumeleni we-photoelectric, lapho ama-photon eshaya izingxenye ezizwela ukukhanya ukuze akhiqize ama-electron, ukukhiqizwa kwala ma-electron kuhleliwe futhi kuhambisana nokusatshalaliswa kwe-Poisson. Izici ze-spectral zomsindo wokudubula ziyisicaba futhi azincikile kubukhulu bemvamisa, ngakho-ke ubizwa nangokuthi umsindo omhlophe. Incazelo yezibalo: Inani lesikwele esimaphakathi sempande (RMS) somsindo wokudubula lingachazwa kanje:

Phakathi kwazo:

e: Ukushaja ngogesi (cishe ama-coulomb angu-1.6 × 10-19)

Idark: Ugesi omnyama

Δf: Ububanzi be-bandwidth

Umsindo wokudubula ulingana nobukhulu bomsinga futhi uzinzile kuzo zonke imvamisa. Kule fomula, i-Idark imelela ugesi omnyama we-photodiode. Okusho ukuthi, uma kungekho ukukhanya, i-photodiode inomsindo wamanje omnyama ongadingeki. Njengoba umsindo ongaphakathi engxenyeni engaphambili ye-photodetector, uma ugesi omnyama umkhulu, umsindo we-photodetector uba mkhulu. Ugesi omnyama uphinde uthintwe yi-voltage yokusebenza ye-bias ye-photodiode, okungukuthi, uma i-voltage yokusebenza ye-bias inkulu, ugesi omnyama uba mkhulu. Kodwa-ke, i-voltage yokusebenza ye-bias ithinta futhi amandla okuhlangana kwe-photodetector, ngaleyo ndlela ithonya isivinini kanye nomkhawulokudonsa we-photodetector. Ngaphezu kwalokho, uma i-voltage ye-bias inkulu, isivinini kanye nomkhawulokudonsa kuba mkhulu. Ngakho-ke, maqondana nomsindo wokudubula, ugesi omnyama kanye nokusebenza komkhawulokudonsa kwama-photodiode, ukwakheka okunengqondo kufanele kwenziwe ngokwezidingo zangempela zephrojekthi.

2. Umsindo Osheshayo we-1/f

Umsindo we-1/f, owaziwa nangokuthi umsindo we-flicker, uvela kakhulu ebangeni lemvamisa ephansi futhi uhlobene nezici ezifana nokukhubazeka kwezinto noma ukuhlanzeka kobuso. Kusukela kumdwebo wawo wesici se-spectral, kungabonakala ukuthi ubuningi bawo be-spectral bancane kakhulu ebangeni lemvamisa ephezulu kunasebangeni lemvamisa ephansi, futhi ngokukhuphuka kwemvamisa izikhathi eziyi-100, umsindo wobuningi be-spectral wehla ngokuqondile ngezikhathi eziyi-10. Ubuningi be-spectral bamandla bomsindo we-1/f buhambisana ngokuphambene nobuningi, okungukuthi:

Phakathi kwazo:

SI(f) : Ubuningi be-spectral yamandla omsindo

I: Okwamanje

f: Imvamisa

Umsindo we-1/f ubalulekile ebangeni lemvamisa ephansi futhi uba buthaka njengoba imvamisa ikhula. Lesi sici senza kube umthombo omkhulu wokuphazamiseka ekusetshenzisweni kwemvamisa ephansi. Umsindo we-1/f nomsindo we-wideband ikakhulukazi uvela kumsindo we-voltage we-amplifier yokusebenza ngaphakathi kwe-photodetector. Kuneminye imithombo eminingi yomsindo ethinta umsindo we-photodetectors, njengomsindo wokunikezwa kwamandla we-amplifier yokusebenza, umsindo wamanje, kanye nomsindo wokushisa wenethiwekhi yokumelana ekuzuzeni kwezifunda ze-amplifier yokusebenza.

3. Umsindo we-voltage kanye nowamanje we-amplifier yokusebenza: Ubuningi be-voltage kanye nowamanje we-spectral buboniswe esithombeni esilandelayo:

Kumasekethe okusebenza kwe-amplifier, umsindo wamanje uhlukaniswe ngomsindo wamanje wesigaba kanye nomsindo wamanje wokuguqula. Umsindo wamanje wesigaba i+ ugeleza ngokumelana kwangaphakathi komthombo ama-R, ukhiqiza umsindo we-voltage olinganayo u1= i+*Rs. I- Umsindo wamanje wokuguqula ugeleza nge-resistor equivalent gain R ukuze ukhiqize umsindo we-voltage olinganayo u2= I-* R. Ngakho-ke uma i-RS yokunikezwa kwamandla inkulu, umsindo we-voltage oguqulwe kusuka kumsindo wamanje nawo mkhulu kakhulu. Ngakho-ke, ukuze kulungiselelwe umsindo ongcono, umsindo wokunikezwa kwamandla (kufaka phakathi ukumelana kwangaphakathi) nawo uyisiqondiso esiyisihluthulelo sokwenza ngcono. Ubuningi bomsindo wamanje abushintshi ngokushintshashintsha kwemvamisa. Ngakho-ke, ngemva kokukhuliswa yisekethe, yona, njengogesi omnyama we-photodiode, yakha ngokuphelele umsindo wokudubula we-photodetector.

4. Umsindo wokushisa wenethiwekhi yokumelana ukuze kuzuze (isici sokukhulisa) wesekethe ye-amplifier yokusebenza ungabalwa kusetshenziswa ifomula elandelayo:

Phakathi kwazo:

k: Okungaguquki kweBoltzmann (1.38 × 10-23J/K)

T: Izinga Lokushisa Eliphelele (K)

R: Umsindo wokushisa wokumelana (ohms) uhlobene nenani lokushisa kanye nokumelana, futhi i-spectrum yawo ithambile. Kungabonakala kufomula yokuthi uma inani lokumelana nokutholakala likhulu, kulapho umsindo wokushisa ukhulu khona. Uma i-bandwidth inkulu, kulapho umsindo wokushisa uzoba mkhulu khona. Ngakho-ke, ukuqinisekisa ukuthi inani lokumelana kanye nenani lomkhawulokudonsa lihlangabezana nezidingo zokuthola kanye nezidingo zomkhawulokudonsa, futhi ekugcineni lidinga umsindo ophansi noma isilinganiso esiphezulu sesignali-kuya-kumsindo, ukukhethwa kwama-resistors okuthola kudinga ukucatshangelwa ngokucophelela futhi kuhlolwe ngokusekelwe ezidingweni zangempela zephrojekthi ukuze kufezwe isilinganiso esifanele sesignali-kuya-kumsindo sesistimu.

Isifinyezo

Ubuchwepheshe bokuthuthukisa umsindo budlala indima ebalulekile ekuthuthukiseni ukusebenza kwama-photodetector namadivayisi kagesi. Ukunemba okuphezulu kusho umsindo ophansi. Njengoba ubuchwepheshe budinga ukunemba okuphezulu, izidingo zomsindo, isilinganiso sesiginali nomsindo, kanye namandla omsindo alinganayo ama-photodetector nawo aya ngokuya ephakama.