2. Work purpose
• Discover basic properties of fiber laser mode-
locke based on NPE;
• Find necessary conditions to mode-lock laser
by NPE.
3. NPE based on phenomena of:
𝑛 𝑧 = 𝑛2 𝑃𝑥 𝑧 + 𝑃𝑦 𝑧
nonlinear refractive index
𝑃𝑥,𝑦 - power of x,y polarization.
In due of this some cross effects arise
between polarizations and lead
to its dynamics
Cross effect absent for linear or circular
polarization
6. The pulse polarization dynamics in the points of cavity. Marker on a curve shows point
in a pulse with highest power.
7. How the scheme works ?
• QWP 1 makes from X polarised pulse a some
polarization state shown as a point 1 in the
previous slide;
• Its state developes as pulse goes in the cavity 1-2-
3;
• The duty of plates pair 3-4 is to move a
polarization state from case of 3 to 4 with pulse
highest part in the X polarization. So trougth the
cavity pass only part of pulse with highest power.
• That’s how that leads the laser to pulsing.
16. Conclusions
• The NPE mode-locked laser exploite a
phenomena of pulse polarization dynamics in
a cavity;
• The use of waveplates allowed us to choose a
right pulse treatment to enchance pulsing.
