Phase modulation active device, method of driving the same, and optical apparatus including the phase modulation active device

A phase modulation active device comprising:

• a phase modulator comprising a plurality of channels, each channel of the plurality of channels configured to modulate a phase of incident light independently from other channels of the plurality of channels, based on a target phase modulation value;
• a signal input unit configured to apply an input signal for phase modulation to the each channel of the plurality of channels;
• and
• a controller configured to control the signal input unit to apply the input signal, which implements a phase modulation value less than the target phase modulation value of a channel, to at least one channel included a channel group including channel of which target phase modulation value is equal to or larger than a predetermined phase value, among the plurality of channels,
• with respect to a portion of channels of the channel group, the input signal being to implement a first phase modulation value less than the predetermined phase modulation value,
• with respect to a remaining portion of channels of the channel group, the input signal being to implement a second phase modulation value less than the predetermined phase modulation value and different to the first phase modulation value.