Quasiperiodic Intensity Oscillations in a Laser Subject to Optical Feedback

where E , A , A and 8 are scaled parameters proportionals to the laser damplng coefficient. the angular frequency of the solitary laser (mod Zn), the feedback rate and the delay of the feedback. respectively. Time s is measured in units of the laser relaxation oscillations period. We have shown that Eq. (*) admits multiple branches of time-periodic states in agreement with the numerical bifurcation diagram of the original laser equations. Our analysis assumed that the delay 8 is an O(1) quantity but in many experiments 8 is numerically larger. We have modiZied the analysis in (1.1 and have found that large delays may lead to a secondary bifurcation to quasiperiodic intensity oscillations. This bifurcation has been suspected in earlier studies but has never been investigated analytically. We shops that these quasiperiodic oscillations are characterized by two distinct frequencies: w1 = 1 and w 2proportional to 1/8. We analyze the bffurcation