Gigahertz Repetition-Rate Pulse Generation in Fiber Lasers Based on Semiconductor Optical Amplifiers

The latest advances in utilizing a novel method for generating gigahertz-repetition-rate pulses in fiber lasers based on semiconductor optical amplifiers are reviewed. This method, based on self-sustained cross-gain modulation in lasers with negative optical feedback, does not require active modulation or the use of saturable absorbers and provides stable generation of subnanosecond pulses. The applicability of the approach has been demonstrated experimentally at repetition rates up to 9.77 GHz. The possibility of broad wavelength tuning in a wide range from 1480 to 1556 nm with preserved pulsed operation mode and control of pulse repetition frequency from 1.85 to 6.2 GHz is also demonstrated. The physical principles underlying the method and its advantages for practical applications in telecommunications, metrology, and spectroscopy are discussed.