Abstract

Different APM laser schemes¹ are popular for short-pulse generation. To avoid instability due to double-cavity configurations, new single-cavity laser schemes for self-starting mode locking have been proposed.^2,3 The basic element of these lasers is a nonlinear active or passive fiber-loop interferometer. Mode locking is due to nonlinear loop reflection and transmission change when light power decreases or increases. The experimentally realized scheme,⁴ based on a two-coupler loop-in-the-ring interferometer,⁵ has a figure-eight form.^3,4 This laser works only with an optical isolator. An analogous scheme without the isolator³ requires additional gain and nonlinear media.

© 1993 Optical Society of America