35-04 Explicit machine computation and programs (not the theory of computation or programming)
Refine
Year of publication
- 2009 (3)
Language
- English (3)
Keywords
- alternate oscillations (1)
- analysis (1)
- bistability (1)
- damping (1)
- delay-differential equations (1)
- direct modulation (1)
- eye diagram (1)
- harmonic mode-locking (1)
- large signal response (1)
- mode-locking (1)
- modulation bandwidth (1)
- optical modes (1)
- passive feedback (1)
- semiconductor laser (1)
- semiconductor ring laser (1)
- small signal response (1)
- switching (1)
- traveling wave equations (1)
- traveling wave model (1)
- unidirectional (1)
Application Area
- D (3)
We study both theoretically and experimentally typical operation
regimes of 40 GHz monolithic mode-locked lasers. The underlying Traveling Wave Equation model reveals quantitative agreement for characteristics of the fundamental mode-locking as pulse width and repetition frequency tuning, as well as qualitative agreement with the experiments for other dynamic regimes. Especially the appearance of stable harmonic mode-locking at 80 GHz
has been predicted theoretically and confirmed by measurements.
Furthermore, we derive and apply a simplified Delay-Differential-Equation model
which guides us to a qualitative analysis of bifurcations responsible for the appearance
and the breakup of different mode-locking regimes. Higher harmonics of mode-locking are predicted by this model as well.
We explore the concept of passive-feedback lasers for direct signal
modulation at 40 Gbit/s. Based on numerical simulation and bifurcation
analysis, we explain the main mechanisms in these devices which are
crucial for modulation at high speed. The predicted effects are
demonstrated experimentally by means of correspondingly designed
devices. In particular a significant improvement of the modulation
bandwidth at low injection currents can be demonstrated.
We use the traveling wave model for simulating and analyzing
nonlinear dynamics of complex semiconductor ring laser devices.
This modeling allows to consider temporal-spatial distributions
of the coun\-ter-pro\-pa\-ga\-ting slowly varying optical fields
and the carriers, what can be important when studying
non-homogeneous ring cavities, propagation of short pulses or fast switching.
By performing numerical integration of the model
equations we observe several dynamic regimes as well as transitions
between them. The computation of ring cavity modes explains some
peculiarities of these regimes.