lect22 - PIN Diode Electric field (depletion region)...

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Electric field (depletion region) Separate photo-generated carriers Photocurrent PIN Diode
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Energy-band diagram for a pin photodiode PIN Diode (eV) 24 . 1 ) m ( g c E
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Photovoltaic Detectors Avalanche Photodiode – Similar structure to that of a PIN diode – Designed to operate near the reverse breakdown voltage – Electric field is much stronger: 10^5V/cm Impact Ionization Process: Because of this strong electric field, electrons and holes acquire sufficient kinetic energy to ionize additional charge carrier when they collide with their crystal lattices.
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Optical Detectors: Applications • Fiber optic communications systems – Receiver uses a GaInAn photodiode – 2.5 Gbits/s data rate – Photovoltaic Detector
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Optical Detectors: Applications • Thermographic camera – Infrared camera operating at wavelengths of ~ 14 um – Thermal Detector • Bolometer
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Optical Detectors: Applications • Neutrino Detector – Super-Kamiokande – 11,000 photomultiplier tubes (PMTs) – Photoemissive Detector
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Noise Average value of electrical current ( P – optical power ): Fluctuations:
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Sources of Noise in Photon Detection Photon Noise: Random arrivals of the photons (Poisson statistics) Photoelectron Noise: Photocarrier-generation process is random Gain Noise: Each detected photon generates a random number of carriers Receiver Circuit Noise: Contribution from resistors, transistors…
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Sources of Noise in Photon Detection
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Other Sources of Noise Background noise: Light from external sources, especially in MIR and FIR (thermal radiation)
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This note was uploaded on 02/12/2012 for the course ECE 414 taught by Professor Alenxendra during the Spring '11 term at Purdue University-West Lafayette.

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lect22 - PIN Diode Electric field (depletion region)...

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