We investigate the occurrence of instabilities related to possible transitions to chaos in specific configurations based on semiconductor lasers. Various scenarios, such as period doubling, frequency locking, quasiperiodicity, and intermittency, are observed experimentally as functions of the control parameters. These are, respectively, the current modulation, external light injection, and delayed feedback. The experimental findings are described and discussed on the basis of semiconductor-laser rate equations.

Intensity instabilities of semiconductor lasers under current modulation, external light injection, and delayed feedback

Integration of the whole mode-locked laser onto a single piece of semiconductor offers a number of advantages, including total elimination of optical alignment processes, improved mechanical stability, and the generation of short optical pulses at much higher repetition frequencies. Semiconductor laser processing technologies were used to implement the colliding-pulse mode-locking (CPM) scheme, which is known to effectively shorten the pulses and increase stability, on a miniature monolithic semiconductor cavity. The principles of and recent progress in monolithic CPM quantum-well lasers are reviewed. >

Monolithic colliding-pulse mode-locked quantum well lasers

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Monolithic colliding-pulse mode-locked quantum-well lasers

An analysis of the pulse-to-pulse timing jitter in an actively mode-locked laser is presented. The model includes spontaneous emission noise, mode-locker driver phase noise, and cavity length detuning. Analytical expressions for the laser pulse train phase noise spectrum, the intensity power spectrum, and the RMS timing jitter are given. The timing fluctuations are characterized by a time constant proportional to the cavity round-trip time times the number of locked modes squared divided by the modulation depth. The contribution from the mode-locker driver phase noise will dominate unless high-stability RF sources are used. The residual timing jitter due to spontaneous emission noise is very sensitive to cavity detuning. >

Theory of timing jitter in actively mode-locked lasers

The equations of combined active and passive mode-locking are solved approximately in the limit when the saturable absorber determines the width of the pulse, and the active modulator the timing. An equation identical with the Adler equation of oscillator phase locking is obtained for the phase of the pulse with respect to the active modulation. In the case of synchronization between the mode-locked pulse-train and the active modulation (time independent solution), the phase of the pulse with respect to the modulation maximum is determined as a function of detuning and modulation (depth. Beyond a critical detuning of the round-trip time Tn from the modulation period TM, synchronisation ceases and the pulses' slip through ' the active modulation with a phase that has a periodic variation superimposed on the uniform slippage rate. Finally, we investigate the effect of noise on the pulse timing. The spectrum of the pulse phase is the same as the spectrum of the phase of an injection-locked single-mode oscill...

H. A. Haus

Papers

Timing of laser pulses produced by combined passive and active mode-locking