Figure-8 laser

Fiber laser with figure-8 ring resonator.In:pumping.Out:emitting light.1:active fiber.2:polarizer.3:optical isolator.4WDM splitter.50:50splitter 50/50.

Afigure-8 laseris afiber laserwith afigure-8-shapedring resonator.It is used for makingpico- andfemtosecondsoliton pulses.The typicalspectrumof such a laser consists of a wide central peak and a few narrow lateral peaks that are placed symmetrically around it. The amplitudes of the narrow peaks are the same as or less than that of the central peak.

Both loops of the resonator work asSagnac loops.Theactive mediumof the laser isoptical fiberwith itscoredoped withrare-earth ions.It is placed asymmetrically with respect to the resonator loops to make a nonlinear difference inphasebetween opposite waves, ensuringmode locking.In 1992 a figure-8 laser was built with a smaller loop length of 1.6 m and a larger loop length of 60.8 m for generation of 315 fs pulses with repetition rate 125 MHz.

Literature

• Agrawal, G. P. (2008).Applications of nonlinear fiber optics.Optics and Photonics Series. Vol. 10 (2nd ed.). Academic Press.doi:10.1016/B978-0-12-374302-2.X5001-3.ISBN978-0-12-374302-2.
• Fermann, M. E.; Galvanauskas, A.; Sucha, G., eds. (2002).Ultrafast Lasers: Technology and Applications.CRC Press.doi:10.1201/9780203910207.ISBN978-0-8247-4349-9.

External links

• "Mode-locked Fiber Lasers: 1.5-μm Femtosecond Erbium Fiber Lasers".Encyclopedia of Laser Physics and Technology.RP Photonics.Retrieved2011-08-12.
• M. K. Islam & P. L. Chu."Stability Analysis of Mode Locked Figure-eight Fiber Laser"(PDF).Progress In Electromagnetics Research Symposium. Archived fromthe original(PDF)on 2016-03-05.Retrieved2011-08-13.