摘要 |
An optical detector and method for detecting incident light utilizes a pair of photosensitive devices in which one of the photosensitive devices is selectively exposed to the incident light to generate differential current signals that can be used to measure the intensity of the incident light. The photosensitive devices may be phototransistors having a silicon-germanium (SiGe) absorption region that is able to convert longer wavelength light, such as 980 nm or 1300 nm light, into current. The SiGe phototransistors may be fabricated on a silicon substrate.
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