Ungawunciphisa kanjani umsindo wama-photodetectors

Ungawunciphisa kanjani umsindo wama-photodetectors

Umsindo wama-photodetectors ikakhulukazi uhlanganisa: umsindo wamanje, umsindo oshisayo, umsindo wesibhamu, umsindo ongu-1/f nomsindo we-wideband, njll. Lesi sigaba sinzima kakhulu. Kulokhu, sizokwethula izici zomsindo ezinemininingwane eminingi nezigaba ukuze sisize wonke umuntu aqonde kangcono umthelela wezinhlobo ezahlukene zomsindo kumasiginali okukhiphayo wama-photodetectors. Ngokuqonda imithombo yomsindo kuphela lapho singakwazi ukunciphisa kangcono futhi sithuthukise umsindo wama-photodetectors, ngaleyo ndlela sithuthukise isilinganiso sesignali-kuya-kumsindo wesistimu.

I-Shot umsindo ukushintshashintsha okungahleliwe okubangelwa imvelo ehlukile yabathwali abashajayo. Ikakhulukazi kumphumela wesithombe kagesi, lapho ama-photon eshaya izingxenye ezizwelayo ukuze akhiqize ama-electron, ukukhiqizwa kwalawa ma-electron akwenzeki futhi kuvumelana nokusatshalaliswa kwe-Poisson. Izici ze-spectral zomsindo wokudubula ziyisicaba futhi azizimele kubukhulu befrikhwensi, futhi ngaleyo ndlela ibizwa nangokuthi umsindo omhlophe. Incazelo yezibalo: Inani lempande yencazelo yesikwele (RMS) lomsindo wokudutshulwa lingavezwa kanje:

Phakathi kwazo:

e: Inkokhelo ye-elekthronikhi (cishe ama-coulombs angu-1.6 × 10-19)

Idark: Umsinga omnyama

Δf: Umkhawulokudonsa

Umsindo wokudutshulwa ulingana nobukhulu bamanje futhi uzinzile kuwo wonke amafrikhwensi. Kufomula, u-Idark umele amandla amnyama e-photodiode. Okusho ukuthi, lapho kungabikho ukukhanya, i-photodiode inomsindo wamanje omnyama ongafuneki. Njengomsindo ongokwemvelo ekupheleni kwangaphambili kwe-photodetector, lapho ukukhanya okumnyama kukhudlwana, kuba mkhulu umsindo we-photodetector. Amandla amnyama nawo athintwa i-voltage yokusebenza echemile ye-photodiode, okungukuthi, lapho i-voltage yokusebenza echemile inkulu, amandla amanje amnyama abe mkhulu. Kodwa-ke, i-voltage yokusebenza echemile nayo ithinta i-junction capacitance ye-photodetector, ngaleyo ndlela ibe nomthelela wesivinini kanye nomkhawulokudonsa we-photodetector. Ngaphezu kwalokho, lapho i-voltage yokuchema inkulu, ijubane elikhulu kanye nomkhawulokudonsa. Ngakho-ke, ngokomsindo wokudubula, ukusebenza okumnyama kwamanje kanye nomkhawulokudonsa wama-photodiode, ukuklama okunengqondo kufanele kwenziwe ngokuvumelana nezidingo zangempela zephrojekthi.

2. 1/f Flicker Umsindo

Umsindo ongu-1/f, owaziwa nangokuthi umsindo olokozayo, uvela kakhulu ebangeni lefrikhwensi ephansi futhi uhlobene nezici ezifana nokukhubazeka kokubalulekile noma ukuhlanzeka kwendawo. Kusuka kumdwebo wesici se-spectral, kungabonakala ukuthi ukuminyana kwe-spectral yamandla kuncane kakhulu ebangeni le-high-frequency kunebanga le-low-frequency, futhi kuzo zonke izikhathi eziyi-100 zokunyuka kwemvamisa, umsindo we-spectral density wehla ngokulandelana izikhathi eziyi-10. Ukuminyana kwe-spectral yamandla womsindo ongu-1/f kuhambisana ngokuphambene nemvamisa, okungukuthi:

Phakathi kwazo:

SI(f) : Ukuminyana kokubukwa kwamandla omsindo

Mina: Okwamanje

f: Imvamisa

Umsindo ongu-1/f ubalulekile kububanzi befrikhwensi ephansi futhi uba buthaka njengoba imvamisa inyuka. Lesi sici senza kube umthombo omkhulu wokuphazamiseka ezinhlelweni zefrikhwensi ephansi. Umsindo ongu-1/f nomsindo we-wideband ikakhulukazi uvela kumsindo we-voltage we-amplifier yokusebenza ngaphakathi kwe-photodetector. Kuneminye imithombo eminingi yomsindo ethinta umsindo wama-photodetectors, njengomsindo wokunikezwa kwamandla wama-amplifiers okusebenza, umsindo wamanje, nomsindo oshisayo wenethiwekhi yokumelana ekuzuzeni amasekhethi okusebenza kwe-amplifier.

3. Umsindo wamandla kagesi nomsindo wamanje we-amplifier yokusebenza: I-voltage ne-spectral density yamanje iboniswa esithombeni esilandelayo:

Kumasekhethi e-amplifier okusebenza, umsindo wamanje uhlukaniswa ngomsindo wamanje osesigabeni kanye nomsindo wamanje oguqulayo. Umsindo wamanje wesigaba i+ ugeleza kumthombo wangaphakathi wokumelana nama-Rs, ukhiqize umsindo wevoltheji olinganayo u1= i+*Rs. I- Umsindo wamanje oguqulayo ugeleza ku-resistor elingana nokuzuza R ukuze ukhiqize umsindo we-voltage olinganayo u2= I-* R. Ngakho-ke lapho i-RS yokunikezwa kwamandla inkulu, umsindo we-voltage oguqulwa emsindweni wamanje nawo mkhulu kakhulu. Ngakho-ke, ukuze kuthuthukiswe umsindo ongcono, umsindo wokuphakela amandla (okuhlanganisa ukumelana kwangaphakathi) nawo uyisiqondiso esibalulekile sokwenza ngokugcwele. Ukuminyana kwe-spectral komsindo wamanje akuguquki nangokuhlukahluka kwamafrikhwensi. Ngakho-ke, ngemva kokukhuliswa yisekethe, yona, njengokukhanya kwamanje kwe-photodiode, yakha ngokuphelele umsindo wokudubula we-photodetector.

4. Umsindo oshisayo wenethiwekhi yokumelana nenzuzo (isici sokukhulisa) sesekethe ye-amplifier yokusebenza ingabalwa kusetshenziswa ifomula elandelayo:

Phakathi kwazo:

k: I-Boltzmann njalo (1.38 × 10-23J/K)

T: I-Absolute Temperature (K)

R: Ukumelana (ohms) umsindo oshisayo uhlobene nezinga lokushisa kanye nenani lokumelana, futhi i-spectrum yayo iyisicaba. Kungabonakala kufomula ukuthi uma likhulu inani lokumelana nenzuzo, kuba mkhulu umsindo oshisayo. Uma umkhawulokudonsa mkhulu, umsindo oshisayo uzoba mkhulu. Ngakho-ke, ukuze kuqinisekiswe ukuthi inani lokumelana nenani lomkhawulokudonsa lihlangabezana kokubili izidingo zokuzuza kanye nezidingo zomkhawulokudonsa, futhi ekugcineni futhi kudinge umsindo ophansi noma isilinganiso esiphezulu sesignali-kuya-nomsindo, ukukhethwa kwezinqamuleli zenzuzo kudinga ukucatshangelwa ngokucophelela futhi kuhlolwe ngokusekelwe ezidingweni zangempela zephrojekthi ukuze kuzuzwe isilinganiso esifanele sesignali-kumsindo wesistimu.

Isifinyezo

Ubuchwepheshe bokuthuthukisa umsindo budlala indima ebalulekile ekuthuthukiseni ukusebenza kwama-photodetectors namadivayisi kagesi. Ukunemba okuphezulu kusho umsindo ophansi. Njengoba ubuchwepheshe bufuna ukunemba okuphezulu, izimfuneko zomsindo, isilinganiso sesignali-kuya-nomsindo, namandla alinganayo omsindo wezithonjana zezithombe nazo ziya ngokuya ziba phezulu.