3. Time regimes: from continuous to femtosecond

3.1 Continuous operation

The continuous regime is the default regime obtained with a simple laser cavity, although some phase-locking or spontaneous triggering phenomena are sometimes observed. If no effort is made to control the laser emission spectrum, this continuous emission is made up of several longitudinal modes in the spectral domain, whose frequencies satisfy the equation (5) . This property is due to the partially inhomogeneous nature of gain broadening in doped optical fibers. The number of modes oscillating in the laser cavity can be reduced by introducing an optical...