5.6: Summary

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Franz X. Kaertner
Massachusetts Institute of Technology via MIT OpenCourseWare

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The main result of this section is, that pure active mode-locking with an amplitude modulator leads to Gaussian pulses. The width is inverse proportional to the square root of the gain bandwdith. A phase modulator leads to chirped Gaussian pulses. A soliton much shorter than the Gaussian pulse due to pure active mode locking can be stabilized by an active modelocker. This finding also has an important consequence for passive mode locking. It implies that a slow saturable absorber, i.e. an absorber with a recovery time much longer than the width of the soliton, is enough to stabilize the pulse, i.e. to modelock the laser.

Bibliography

[1] H. A. Haus, ”Short Pulse Generation”, in Compact Sources of Ultrashort Pulses, ed. by I. N. Duling III, Cambridge University Press (1995).

[2] D. J. Kuizenga and A. E. Siegman, ”FM and AM Mode Locking of the Homogeneous Laser - Part I: Theory,” IEEE J. of Quantum Electron. QE-6, pp. 694 — 708 (1970).

[3] D. J. Kuizenga and A. E. Siegman, ”FM and AM modelocking of the homogeneous laser - part I: theory,” IEEE J. Qunat. Electron. 6, pp. 694 — 701 (1970).

[4] H. A. Haus, ”A Theory of Forced Mode Locking”, IEEE Journal of Quantum Electronics QE-11, pp. 323 - 330 (1975).

[5] H. A. Haus and Y. Silberberg, ”Laser modelocking with addition of nonlinear index”, IEEE Journal of Quantum ElectronicsQE-22, pp. 325 - 331 (1986).

[6] F. X. Kärtner, D. Kopf, U. Keller, ”Solitary pulse stabilization and shortening in actively mode-locked lasers,” J. Opt. Soc. of Am. B12, pp. 486 — 496 (1995).

[7] D. Kopf, F. X. Kärtner, K. J. Weingarten, U. Keller, ”Pulse shortening in a Nd:glass laser by gain reshaping and soliton formation, Opt. Lett. 19, 2146 — 2248 (1994).

[8] J.D. Kafka and T. Baer, ”Mode-locked erbium-doped fiber laser with soliton pulse shaping”, Opt. Lett.14, pp. 1269 — 1271 (1989).

[9] K. Smith, R. P. Davey, B. P. Nelson and E.J. Greer, ”Fiber and Solid- State Lasers”, (Digest No. 120), London, UK, 19 May 1992, P.1/1-4.

[10] J.D. Kafka, M. L. Watts and J.W.J. Pieterse, ”Picosecond and fem- tosecond pulse generation in a regeneratively mode-locked Ti:Sapphire laser”,IEEE J. Quantum Electron. QE-28, pp. 2151 — 2162 (1992).

[11] F. Fontana, N. Ridi, M. Romagnoli, P. Franco, ”Fully integrated 30 ps modelocked fiber laser electronically tunable over 1530 - 1560 nm”, Opt. Comm. 107, pp. 240 — 244 (1994).

[12] D. J. Jones, H. A. Haus and E. P. Ippen, ”Solitons in an Actively Mod- elocked Fiber Laser,” to appear in Opt. Lett.

[13] U. Keller, T. H. Chiu and J. F. Ferguson, ”Self-starting femtosecond mode-locked Nd:glass laser using intracavity saturable absorber,”- Opt. Lett. 18, pp. 1077 - 1079 (1993).

[14] H. A. Haus and A. Mecozzi, ”Long-term storage of a bit stream of solitons”, Opt. Lett. 21, 1500 — 1502 (1992).