cavity soliton switching and pattern formation in an optically-pumped vertical-cavity semiconductor...

Cavity soliton switching and pattern formation

in an optically-pumpedvertical-cavity semiconductor

amplifier

Laboratoire de Photonique et de NanostructuresLPN-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 lineSerial 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)

F aÂ²R

1

a

R

~100 m

~10 m

substrate

GaAs

Reflected beam

Control beam

Holding beam

Bragg MirrorBragg Mirror

Pump

Optical pumping

pump uniformity

thermal management

2aF

R

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-matterinteraction diffraction

carrier recombinationnon-radiative radiative carrier diffusion

Injected field/holding beam

2

22 2

(1 ) 2 ( )( 1)

( ( 1) )

iE

i E E iC i N E i EtN

N N N E D Nt

Modulation Instability

Intracavity I

k

i

PWI

MICS Rolls+Hex.

= 5, = -2, C = 0.45, = 2

Injected I

Intracavity I

Sample : OP-VCSOA on SiC substrate

Ti:Sa injection @ 883.93nm

12 mm

MOCVD grown AlGaAs microcavity with GaAs active medium

Optimized aperiodic mirrors : optical pumping efficiency, heat managementSubstrate bonding on SiC

[S. Barbay,Y. Ménesguen, I. Sagnes, and R. Kuszelewicz, App. Phys. Lett. vol 86, 151119 (2005)]

Laboratoirede Photonique et de Nanostructures

Pattern formation

890.98 nm 889.95 nm 889.27 nm

888.23 nm

Pump + coherent injectionPump

120 m

Spontaneous formation of CS

Pump

120 m

Increasing Pumping

Pump + injection 888.38nm


Local intensity vs

injection beam intensity

Injected intensity

Loc

al in

tens

ityBistability


Periodic coherent writing / erasure of a single CSO

utpu

t int

ensi

ty

Injected intensity

phase shifted local excitation

in phase local excitation

Coherent injection

Optical pump

Local pulsed excitation

sample plane


Periodic coherent writing / erasure of a single CS with 100ns pulses

Local intensity

Writing pulse phase mismatch

100ns pulses trigger


Incoherent writing / erasure

Can we write with incoherent local excitation ?

Cavity solitons in optical amplifiers are coherent objectsbut...

one can play on carriers


Incoherent Writing with short pulses

60 ps writing pulse60 ps writing pulseLocal pump modulation


Fast incoherent writing : 60ps pulses

CS off

CS on~2ns


Fast incoherent erasure : 60ps pulses

CS on

CS off

~5 ns


Conclusion

Coherent writing/erasure of CS

Incoherent writing/erasure of CS

Questions : incoherent switch on/off dynamics

possibility to suppress the delay ?

cavity soliton switching and pattern formation in an optically-pumped vertical-cavity semiconductor...

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