LiDAR: optical receiver amplifier with 135dB dynamic range in SiGe
One of the main problems at the receiver side of the LiDAR systems is the high amplitude variation of the reflected optical pulse, depending on the measurement distance, reflectivity, and angle of the reflection.
The dynamic range of the reflected signal depends on the application and can reach seven or even more orders of magnitude. Such a kind of optical signal can easily saturate or even damage conventional optical receivers based on a linear trans-impedance amplifier (TIA), thus making it insensitive to the incoming optical signal. The proposed optical receiver overcomes this problem by using input-current logarithmic compression.
The concept is shown in Figure:
