Table of Contents
What Are Tunable Fiber Lasers and How They Work
Tunable fiber lasers’ main characteristic is the ability of the wavelength to tune or adjust. This process is referred to as wavelength tuning. Tuning of the fiber laser may occur over a wide range, which is highly desired for certain applications.
Wavelength Tuning and Speed Requirements
Tunable fiber lasers are called wavelength agile if the wavelength tuning may be performed at high speed. Fast wavelength tuning is important for dynamic environments in which the laser may be used. Generally, single-frequency fiber lasers can be continuously tuned over a certain range; other laser types can be tuned to only access discrete wavelengths. Tuning of non-single-frequency lasers over a large range leads to mode hops.
Among fiber lasers, rare-earth-doped fiber lasers can be tuned over a wide range of wavelengths. For example, ytterbium fiber lasers are tunable over tens of nanometers. Widely tunable fiber lasers are Raman fiber lasers.
Key Applications of Tunable Fiber Lasers
Tunable fiber laser systems are used in a variety of different applications:
- Spectroscopy. A high-frequency resolution of transmission recording is possible by using tunable lasers. Tunable fiber lasers are also used in LIDAR.
- Laser cooling. Some methods of laser cooling require tunable lasers that can be adjusted very precisely.
- Isotope separation. The process of isotope separation with the use of a tunable laser consists of adjusting the laser wavelength to atomic resonances first and later tuning it to a particular isotope to ionize it and deflect it with an electric field.
- Optical fiber communications. Tunable fiber lasers are often used as a spare laser in case the main fixed wavelength laser breaks down. In this situation, a wavelength-tunable laser is tuned to the wavelength of a particular channel that has failed.
- Optical frequency metrology. In optical frequency metrology, the laser needs to be stabilized to a certain standard, e.g., an absorption cell, an optical reference cavity.