Analysis of Self-Pulsation in Distributed Bragg Reflector Laser based on Four-Wave Mixing

Transcription

1 Analysis of Self-Pulsation in Distributed Bragg Reflector Laser based on Four-Wave Mixing P. Landais 1, J. Renaudier 2, P. Gallion 2 and G.-H.Duan 3 1 School of Electronic Engineering, Dublin City University, Dublin 9, Ireland. 2 Département Communications et Electronique, Ecole Nationale Supérieure des Télécommunications, 46 rue Barrault, Paris Cedex 13, France 3 Alcatel Research & Innovation, Route de Nozay, Marcoussis, France

2 Outline Motivations Presentation of DBR SP laser Device structure Device characteristics Presentation of model Theoretical results Conclusions

3 Motivations Increase of network capacity Improve transmission distance Transparency, Capacity and speed. Development of: All-optical logic functions 3R regeneration (Re-amplify, Re-time, Re-shape) Problems to be solved: Simple and robust operation conditions, Clock quality to be comparable with the electronic approach, To reach the ITU requirement.

4 Candidates Hybrid system: photodiode, high-q filter, power amplifier, high speed laser or modulator Fibre: stimulated Brillouin scattering Injection locking Fabry-Perot laser Mode-locked lasers Self-pulsating lasers: Distributed feedback laser Distributed Bragg reflector Mode beating leading to self-pulsation

5 DBR lasers for all-optical clock recovery at 40 GHz 3 section devices including active, phase and Bragg sections Bragg section 200µm Polarization insensitive bulk active layer, nearly square (0.6 µm width and 0.4 µm thickness) buried ridge waveguide Phase section 130µm Phase section for the fine tuning of the lasing wavelength Active section 790µm Bragg section providing a wavelength selection (central wavelength and number of modes) InP p TE/TM discrimination ->lasing only at TE mode InP n ion implantation

6 System experiment at 40 Gbit/s Incoming signal Clock at 40 GHz Phase noise analyser Photodiode RF analyser SP-DBR Oscilloscope Recovered clock at 40 GHz

7 Locking of the SP laser by a clock signal at 40 GHz Spectrum analyzer Phase noise measurement Locked Free-running z H / c B d Rocovered clcok Recovered Input clock clcok Input clock Frequency Fréquence (Hz) (Hz)

8 SP frequency tuning and optical spectrum f SP (GHz) 42,2 42, , Optical spectrum ,8 41, I B (ma) I B (ma) Photocurrent spectrum

9 Confirmation of self-pulsation phenomenon I b I a Acoustooptic modulator 160 MHz DBR laser Β<f SP Photodiode RF spectrum analyser 1 Photocurrent Spectrum Δν 1 = 30.5 MHz Δν 2 = 24.5 MHz λ Δν 3 = 24.5 MHz Δν 4 = 26 MHz Δν i Phase correlation between different modes through intracavity four wave mixing Self-pulsation Δν RF =400 khz < Δν i

10 Approach & Hypotheses Beating E 1 E 2 * Beating E 2 E 3 * 3 modes 2ϕ 2 - ϕ 3 E 2 (E 2 E 3 * ) mode 2> mode 1> mode 3 P s = E E E 1 2 ϕ 1 E 2 (E 1 E 2 *) FWM due to the interband effect is dominant even if Ω sp >1/τ e. Adiabatic approximation. (E 1, ϕ 1 ) ω Ω sp (E 2, ϕ 2 ) Ω (E 3, ϕ 3 ) sp

11 Theoretical model

12 Analysis Chart Differential Equation Systems Locking condition Steady State d/dt=0 Perturbation Analysis up to 1 st order perturbation. Fourier Transformation Phase noise density for each mode

13 Spectral Noise Density If det(jω I-M) 0

14 Parameters

15 Results (1): Spectral Noise Density of mode 2 phase

16 Results (2)

17 Conclusions All-optical clock recovery using a SP DBR laser demonstrated at 40 GHz with: Input power level dbm when λ in out of the gain region 4-6 dbm when λ in in the gain region 1 db polarization sensitivity RMS jitter (sampling scope) : < 1ps ER_out of 11 db Theoretical investigation based on FWM effect Rate equation of the phase and amplitude of 3 modes. Steady state analysis Condition for SP. Small signal analysis Phase correlation in SP DBR laser through FWM. Definition of SP regime.