Modeling and Technologies of Ultrafast Fiber Lasers

The generation and control of ultrashort optical pulses are rapidly growing areas of photonics with many emerging applications. This is primarily due to the fact that short optical pulses allow the probing of basic physics of light/matter interactions in the sub-picosecond regime, which in turn has opened up a range of new applications fromhigh-bit-rate optical telecommunications tomaterial processing at fundamental frequencies, usually around 1mm, in addition to various biomedical diagnostics at frequency-doubled wavelengths. The requirements for simplicity, maintenance, and reliability, however, have not beenmet by conventional ultrafast technology, formerly based on solid-state lasers. Over the past decade much attention has been given to fiber lasers for the generation of ultrashort pulses, owing to various advantages it has over other solid-state lasers. Indeed, the recent growth of the telecom industry has resulted in the development of a mature fiber technology with reliable and costeffective components, which makes suitably designed fiber lasers real contenders as alternatives to conventional solid state lasers. The waveguide geometry of fiber lasers not only simplifies many alignment issues, it also distributes heat generated by optical pumping over the length of the fiber. This is significant for reducing both the thermal management of the laser as well as the risk of damage to the medium itself. To achieve higher energies, fiber lasers have the potential for power scalability by implementing cladding pumping technology, which renders them ideal light sources for boosting the energy and brightness, with relative immunity from the thermal problems that have a serious impact on solid-state lasers via thermal lensing. Another attractive feature of optical fiber is the broad emission linewidth of a glass host, in contrast to crystalline hosts conventionally employed by bulk solid-state-lasers. The broad fluorescence spectrum makes different fiber gain media attractive for wavelength tunable continuous wave (CW) or pulsed sources.Most ultrafast laser systems