Cavity soliton switching and pattern formation in an optically-pumped vertical-cavity semiconductor amplifier Laboratoire de Photonique et de Nanostructures LPN-CNRS/UPR20, Marcoussis, France S. Barbay, Y. Ménesguen, X. Hachair, L. Leroy, I. Sagnes, R. Kuszelewicz

Introduction Cavity solitons : self-localized structures high intensity peaks on a low intensity background in a large diameter cavity Properties : Independant of each other Can be written & erased by control beam Can be manipulated by phase gradients

Applications Phase gradient Pulsed beam Optical delay line Serial to parallel conversion Reconfigurable optical memory Control beam Holding beam phase profile

VCSOA characteristics Nonlinear cavity with large Fresnel number injected by coherent beam (holding beam) a R ~100  m ~10  m substrate GaAs Reflected beam Control beam Holding beam Pump Optical pumping pump uniformity thermal management

Theoretical model [M. Brambilla, L. Lugiato, F. Prati, L. Spinelli, W. Firth, PRL 79, 2042 (1997)] E : intracavity electric field N : carrier density  = 1  transparency  = 1+1/2C  laser threshold coupling to the cavity radiation-matter interaction diffraction carrier recombination non-radiative radiative carrier diffusion Injected field/holding beam

Modulation Instability Intracavity I kk  ii PWI MI CS Rolls+Hex.  = 5,  = -2, C = 0.45,  = 2 Injected I Intracavity I

Sample : OP-VCSOA on SiC substrate Ti:Sa nm 12 mm MOCVD grown AlGaAs microcavity with GaAs active medium Optimized aperiodic mirrors : optical pumping efficiency, heat management Substrate bonding on SiC [S. Barbay,Y. Ménesguen, I. Sagnes, and R. Kuszelewicz, App. Phys. Lett. vol 86, (2005)]

Laboratoire de Photonique et de Nanostructures Pattern formation nm nm nm nm Pump + coherent injection Pump 120  m

Spontaneous formation of CS Pump 120  m Increasing Pumping Pump + injection nm

Laboratoire de Photonique et de Nanostructures Local intensity vs injection beam intensity Injected intensity Local intensity Bistability

Laboratoire de Photonique et de Nanostructures Periodic coherent writing / erasure of a single CS Output intensity Injected intensity  phase shifted local excitation in phase local excitation Coherent injection Optical pump Local pulsed excitation sample plane

Laboratoire de Photonique et de Nanostructures Periodic coherent writing / erasure of a single CS with 100ns pulses Local intensity Writing pulse phase mismatch 100ns pulses trigger

Laboratoire de Photonique et de Nanostructures Incoherent writing / erasure Can we write with incoherent local excitation ? Cavity solitons in optical amplifiers are coherent objects but... one can play on carriers

Laboratoire de Photonique et de Nanostructures Incoherent Writing with short pulses 60 ps writing pulse Local pump modulation

Laboratoire de Photonique et de Nanostructures Fast incoherent writing : 60ps pulses CS off CS on ~2ns

Laboratoire de Photonique et de Nanostructures Fast incoherent erasure : 60ps pulses CS on CS off ~5 ns

Laboratoire de Photonique et de Nanostructures Conclusion Coherent writing/erasure of CS Incoherent writing/erasure of CS Questions : incoherent switch on/off dynamics possibility to suppress the delay ?