| 摘要 |
Described are a device and a method for determining a wavelength of light incident on a device having an upper photodiode vertically disposed on a lower photodiode. Currents generated by the upper and lower photodiodes in response to the incident light are measured. The wavelength of the light is determined in response to the measured currents and a predetermined correspondence between the currents from the photodiodes as a function of wavelength. In one embodiment, bias voltages applied to the photodiodes are changed and modified currents are measured. The wavelength is determined in response to the measured currents and a predetermined correspondence between the currents from the two photodiodes as a function of wavelength and bias voltage.
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