Meaning
A dynamic optimization method used to restore the planar or spherical phase profile of an optical wave that has been distorted by a turbid medium. Through wavefront correction, a deformable mirror or spatial modulator actively manipulates the local phase front of the light beam to counteract phase errors. This compensation is necessary in ground-to-satellite laser communications to prevent signal degradation caused by atmospheric turbulence.
The process restores the coherence of the incoming signal.
Sensor Interface
The feedback loop relies on a wavefront sensor to measure the local phase gradient of the light beam. When wavefront correction is active, the sensor output is digitized and processed by a controller to calculate the actuator displacements. This interface requires low latency to ensure that the compensation matches the current state of the medium.
Control Algorithm
The calculation of the correction signal typically employs matrix multiplication to map sensor outputs to actuator control voltages. If wavefront correction fails to converge quickly, the residual phase error increases and degrades the imaging performance of the system. The control system must use noise-filtering techniques to prevent actuator overshoot and saturation.
Dynamic Bandwidth
The rate of phase fluctuation determines the necessary correction frequency of the system. When wavefront correction is performed under high-wind conditions, the control loop must update at several kilohertz. This rapid response prevents phase errors from degrading the beam quality.
