Alberto Barsella

Rate equations model for semiconductor lasers with multilongitudinal mode competition and gain dynamics

A novel multilongitudinal-mode rate-equations description of the semiconductor laser is presented. The model includes gain interactions among the longitudinal modes due to e.g., spatial hole burning. The parameters have been obtained from a real device, in order to be able to compare with the simulations. The results are in good qualitative agreement with the measurements.

Experimental measurements of the ridge spacing influence on the frequency response and optical spectrum of laterally coupled laser diodes

The objective of this work is to analyse the dependence of the frequency response of Laterally Coupled Diode Lasers (LCDL) focusing on the separation between the laser ridges. A detailed study of the integrated optical spectra and frequency response is presented for LCDLs with 300 μm cavity length and separation between the ridges of 2, 4, 6, 8 and 10 μm. This study is of major importance as it defines the range of frequency locking for each ridge spacing and also its dependence on the bias conditions applied.

Role of longitudinal mode dynamics in laterally coupled lasers

Our report focuses on the strong kink found in the P-I output of an asymmetric twin stripe semiconductor laser. A multi longitudinal mode model is used to describe the system. The model allows for asymmetric coupling of the two lasers and also accounts for multi longitudinal effects within and in-between the lasers.

Dynamics of laterally coupled semiconductor lasers: transition to chaos

A method for the investigation of the dynamics of two semiconductor lasers, grown side-by-side on the same wafer to enhance the lateral optical coupling, is presented. Using steady state analysis, parameter regimes of relevant dynamics are identified. This is completed by a spectral analysis, were two routes to chaos are implicated. Finally, we confirm the calculations by showing an avoided crossing type of behavior for the coupling strength.

Theory and experiment of laterally coupled multi-longitudinal-mode semiconductor lasers

This report presents simulations and measurements of multimode dynamics in the twin-stripe laser resulting from complicated gain competition effects. The theory is based on a novel multi-longitudinal rate equations model, while accounting for both coherent and incoherent lateral coupling between the lasers. The experiments allowed measurements of RIN and optical power spectra for each laser separately as functions of the independently varied stripe currents and yielded sufficient data that were used to extract parameter values for the simulations. On the basis of the experimental data and the results of simulations it can be concluded that the operation predominantly takes place on several longitudinal modes in both lasers and that the lateral coupling is of a global nature, coupling between the two combs of longitudinal modes. This introduces highly complex inter and intra-stripe mode-competition effects resulting in various types of dynamics that adequately explains the complicated bifurcation structure observed in thesse devices when the current i varied.

Multi-longitudinal mode rate equation model for diode lasers.

A novel multi-longitudinal-mode rate-equations description of the Fabry-Perot type semiconductor laser is presented. The model includes gain dynamics among the longitudinal modes due to e.g. spatial hole burning.

Understanding the twin-stripe diode laser : a multimode perspective

A multimode model is necessary to describe the behavior observed in a twin stripe diode laser. We will use a single-stripe version of the device to calibrate the parameters enabling the model to be used in the description and analysis of the twin-stripe lasers.