Tunable laser application in optical communication

Tunable lasers network applications can be divided into two parts: static applications and dynamic applications.

In static applications, tunable laser wavelength is set in the course does not change over time. The most common application of static laser is used as a source of alternative, i.e., for use in dense wavelength division multiplexing (DWDM) transmission system, so that a tunable laser to act as a plurality of fixed wavelength laser and a flexible back-up source of the laser can be reduced by the number of systems required to support all the different wavelengths of the line card.

Static applications, the main requirements for tunable laser is the price, output power and spectral characteristics, ie width and stability and it should replace the fixed-wavelength laser fairly. Wavelength tunable range greater the cost, the better, without the need to adjust the speed more quickly. Currently, with a precision of DWDM tunable laser system more and more applications.

Future, as a backup tunable lasers also require faster response speed. When a DWDM channel failure, a tunable laser can automatically enable it back to work. To achieve this function, the laser must be adjusted and locked at a wavelength of failure within 10 ms or less time, so as to ensure that the entire recovery time is shorter than the synchronous optical network requirements of 50 milliseconds or less.

In dynamic applications require a tunable laser wavelength can be changed regularly at work, in order to enhance the flexibility of the optical network. Such applications are generally required to provide dynamic wavelength in order to join or propose a wavelength from one network segment to meet the capacity required changes. It has been proposed a simple and more flexible ROADMs structure: this is based on use of tunable lasers and tunable filters architecture. Tunable lasers can add to the system certain wavelength, and tunable filter can filter out certain wavelengths from the system. Tunable lasers can also address cross-coupling inside the light wavelength blocking problems. To avoid this problem optical switching interface - Currently, most optical cross-coupled fiber ends using light - electricity. If you are using tunable lasers at the input to the OXC input, you can choose to protect certain wavelengths of light waves with a clear path to the end.

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