Conversion of optical signal into an electric one. Detector Conversion of optical signal into an electric one.

Types of photodiodes PIN and Avalanche Photodiodes P – I - N Avalanche effect

Doping element selection? Semiconductor bandgaps  Depends on chosen wavelength!

Si vs Ge vs InGaAs InGaAs is the best material choice for our application.

DIY or off-the-shelf? Maybe… APD individual parts Femto HCA-S-200M-IN-FC Laser Components A-CUBE-I200-25 Cheap (~ £200 ex VAT) Does not include bias circuit, control, power supply, etc Needs effort + knowledge to build PIN detector All-in-one ~ 1515 (ex VAT) with power supply Responsivity: 0.85 A/W NEP: 5.2 pW/√Hz APD detector £2,180 (ex VAT) Responsivity: ~ 8.75 A/W NEP: 0.425 pW/√Hz Maybe…

Winner: Thorlabs APD110C Wavelength Range: 900 - 1700 nm Output Bandwidth: up to 50MHz Responsivity @ 1300nm: 8.8 A/W M factor (Gain): 10 (fixed) Minimum NEP: 0.46 pW/√Hz No temperature compensation Price: £1,580 (ex VAT), including power supply Best Value for £ System works