| 摘要 |
A method of measuring optical power by means of an avalanche photodiode (1) comprises generating an electrical signal in response to and as an indication of the optical power (Pin) incident on the photodiode. When the incident optical power (Pin) is lower than a selected limit value (P1), the electrical signal is determined as a function of a current (Id) generated in the photodiode (1) by the optical power. When the incident optical power exceeds this limit value, the current in the photodiode (1) is limited to a constant value (Imax). The electrical signal is determined when the incident optical power (Pin) exceeds the limit value (P1) so that it comprises a contribution which is a function of the voltage (Vd) across the photodiode. A corresponding optical receiver comprises means for determining the electrical signal in response to a current (Id) in the photodiode, and means (3) for limiting the current in the photodiode (1) to a constant value (Imax) when the incident optical power (Pin) exceeds a selected limit value (P1). Further, the receiver comprises means (10, 11) for determining the electrical signal so that it comprises a contribution which is a function of the voltage (Vd) across the photodiode when the incident optical power (Pin) exceeds the limit value (P1). |
