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Tunable Fiber Lasers’ Impact on Future Optical Communication Systems

Tunable fiber lasers are enabling a broad range of applications today and in the near future. There are several technologies, which show promise of being able to address some market segments. Tunable fiber lasers are valuable for a variety of different applications, like spectroscopy, photochemistry, optical communications, laser cooling, metrology or medical treatments. These applications require tunable lasers as they provide an ability to specifically adjust their wavelength.
The distinctive feature of the tunable fiber laser is a wavelength of operation, which can be altered in a controlled manner. Only several types of fiber lasers allow continuous tuning over a significant range. Tunable fiber lasers are usually operating in a continuous way with a small emission bandwidth, although some Q-switched and mode-locked fiber lasers can also be wavelength tuned. There are many types and categories of tunable fiber lasers such as excimer fiber lasers, gas fiber lasers (CO2 lasers, He-Ne lasers, and suchlike), dye fiber lasers (liquid and solid state), semiconductor crystal and diode lasers, and free electron lasers. Tunable fiber lasers find applications in spectroscopy, photochemistry, atomic vapor laser isotope separation, and optical communications.
Among fiber lasers, rare-earth-doped fiber lasers have the ability to be tuned over a wide range of wavelengths. For example, ytterbium fiber lasers are tunable over tens of nanometers. Tunable fiber lasers that are widely tunable are Raman fiber lasers.
Tunable fiber laser systems are used is a variety of different applications:

  1. Spectroscopy

A high-frequency resolution of transmission recording is possible by using tunable lasers. Tunable fiber lasers are also used in LIDAR.

  1. Laser cooling

Some methods of laser cooling require tunable lasers that can be adjusted very precisely.

  1. 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 tuning it to a particular isotope to ionize it and deflect it with an electric field.

  1. 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.

  1. 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.
Prices for fixed and tunable fiber lasers are not yet equivalent, however. Although some tunable types are priced like fixed-wavelength devices, they are tunable over only very narrow ranges, about 3-4 nm. Those fiber lasers that can be tuned across wide wavelength ranges remain at least two or three times as expensive as their fixed counterparts. Such high price on tunable fiber lasers is explained by specific features: the increased complexity of manufacturing them, the extra testing required, and the newness of the technology, which has yet to reach true volume demand. As demand for tunable lasers rises, their prices will come down. Laser manufacturers claim the price premium for a widely tunable laser will drop to about 15-20 percent above that of a fixed laser anyway.
The significantly favorable changes in demand for tunable fiber lasers will occur in parallel with their application to make optical networks more flexible. Nowadays fiber optic networks based on different types of fiber optic devices are essentially fixed: the optical fibers are connected into pipes with huge capacity but little reconfigurability. It is almost impossible to change how that capacity is deployed in real time. In addition to this, there is a problem in choosing a wavelength for a channel: as traffic is routed through a network, certain wavelengths may be already in use across certain links. Tunable fiber lasers will ease a switch to alternative channels without swapping hardware or re-configuring network resources. The benefits gained from the use of tunable fiber lasers are in the time it takes to actually deliver different types of services. Undoubtedly, tunable fiber lasers can dramatically improve fiber optic networks efficiency and will play an important role in enabling future dynamically reconfigurable optical networks, along with optical switches and semiconductor optical amplifiers.
Optromix is a fiber laser vendor, which develops and manufactures a broad variety of fiber lasers, СО₂ lasers, Ti: Sapphire lasers, dye lasers, and excimer lasers. We offer simple erbium laser and ytterbium laser products, as well as sophisticated laser systems with unique characteristics, based on the client’s inquiry.
We manufacture lasers using our own technologies based on the advanced research work and patents of international R&D team. Laser processes are high quality, high precision, easily-automated manufacturing solutions that provide repeatability and flexibility.
If you are interested in fiber laser systems, please contact us at info@optromix.com