Locking range of coherently combined fiber lasers with tunable fiber gratings

The locking range in coherently combined fiber lasers was studied by means of the reflection distribution function of the tunable fiber gratings.After comparing the threshold,it was seen that the oscillation wavelength of the coherent radiation occurred near the average of the two Bragg wavelengths.The result shows that the constituent lasers can be coherently combined when the Bragg wavelength difference between the two fiber gratings is small enough.