Editing Mode locking (section)

=== Error signal generation ===
The reason for generation to create error signals is to create an electronic signal which is proportional to the laser's deviation from a particular set frequency or phase, which is called a "lock point". If the laser frequency is large, then the signal is positive; if frequency is very small, then the signal is negative. The point where the signal is zero is called a lock point. Laser locking based on an error signal which is a function of frequency is called frequency locking and if the error signal is a function of phase deviation of laser then this locking is referred to as phase locking. If the signal is created using an optical setup involving references like frequency references, then by using the reference, the optical signal is directly converted into frequencies which can be detected directly. The other way is to record the signal using a photodiode or camera and further change this signal electronically.