The effect of proton bombardment on semiconductor saturable absorber structure

Abstract

Carrier lifetime reduction resulting from proton bombardment of InGaAs/InP-based semiconductor saturable absorbers was studied experimentally, using a standard degenerate, cross-polarized pump-probe technique. Proton bombardment reduced carrier lifetimes by as much as a factor of 40 at low optical excitation densities. For high fluences, significant induced absorption was observed. The recovery of this excited state absorption did not show as significant a dependence on the level of proton bombardment. It is possible that the cause of this induced absorption - carriers outside the InGaAs quantum wells, highly excited carriers, or those trapped in satellite valleys - is not sensitive to the effects of bombardment. Also, the bombardment-created defects may saturate at such high fluences. The detrimental side-effects of proton bombardment - reduced modulation depth and increased non-saturable loss - have been shown to be mitigated with a short post-growth anneal. Finally, modelocking was demonstrated with the proton-bombarded samples in an erbium fiber laser.

Carrier lifetime reduction resulting from proton bombardment of InGaAs/InP-based semiconductor saturable absorbers was studied experimentally, using a standard degenerate, cross-polarized pump-probe technique. Proton bombardment reduced carrier lifetimes by as much as a factor of 40 at low optical excitation densities. For high fluences, significant induced absorption was observed. The recovery of this excited state absorption did not show as significant a dependence on the level of proton bombardment. It is possible that the cause of this induced absorption - carriers outside the InGaAs quantum wells, highly excited carriers, or those trapped in satellite valleys - is not sensitive to the effects of bombardment. Also, the bombardment-created defects may saturate at such high fluences. The detrimental side-effects of proton bombardment - reduced modulation depth and increased non-saturable loss - have been shown to be mitigated with a short post-growth anneal. Finally, modelocking was demonstrated with the proton-bombarded samples in an erbium fiber laser.

Carrier lifetime reduction resulting from proton bombardment of InGaAs/InP-based semiconductor saturable absorbers was studied experimentally, using a standard degenerate, cross-polarized pump-probe technique. Proton bombardment reduced carrier lifetimes by as much as a factor of 40 at low optical excitation densities. For high fluences, significant induced absorption was observed. The recovery of this excited state absorption did not show as significant a dependence on the level of proton bombardment. It is possible that the cause of this induced absorption - carriers outside the InGaAs quantum wells, highly excited carriers, or those trapped in satellite valleys - is not sensitive to the effects of bombardment. Also, the bombardment-created defects may saturate at such high fluences. The detrimental side-effects of proton bombardment - reduced modulation depth and increased non-saturable loss - have been shown to be mitigated with a short post-growth anneal. Finally, modelocking was demonstrated with the proton-bombarded samples in an erbium fiber laser.

Carrier lifetime reduction resulting from proton bombardment of InGaAs/InP-based semiconductor saturable absorbers was studied experimentally, using a standard degenerate, cross-polarized pump-probe technique. Proton bombardment reduced carrier lifetimes by as much as a factor of 40 at low optical excitation densities. For high fluences, significant induced absorption was observed. The recovery of this excited state absorption did not show as significant a dependence on the level of proton bombardment. It is possible that the cause of this induced absorption - carriers outside the InGaAs quantum wells, highly excited carriers, or those trapped in satellite valleys - is not sensitive to the effects of bombardment. Also, the bombardment-created defects may saturate at such high fluences. The detrimental side-effects of proton bombardment - reduced modulation depth and increased non-saturable loss - have been shown to be mitigated with a short post-growth anneal. Finally, modelocking was demonstrated with the proton-bombarded samples in an erbium fiber laser.

Carrier lifetime reduction resulting from proton bombardment of InGaAs/InP-based semiconductor saturable absorbers was studied experimentally, using a standard degenerate, cross-polarized pump-probe technique. Proton bombardment reduced carrier lifetimes by as much as a factor of 40 at low optical excitation densities. For high fluences, significant induced absorption was observed. The recovery of this excited state absorption did not show as significant a dependence on the level of proton bombardment. It is possible that the cause of this induced absorption - carriers outside the InGaAs quantum wells, highly excited carriers, or those trapped in satellite valleys - is not sensitive to the effects of bombardment. Also, the bombardment-created defects may saturate at such high fluences. The detrimental side-effects of proton bombardment - reduced modulation depth and increased non-saturable loss - have been shown to be mitigated with a short post-growth anneal. Finally, modelocking was demonstrated with the proton-bombarded samples in an erbium fiber laser.

Carrier lifetime reduction resulting from proton bombardment of InGaAs/InP-based semiconductor saturable absorbers was studied experimentally, using a standard degenerate, cross-polarized pump-probe technique. Proton bombardment reduced carrier lifetimes by as much as a factor of 40 at low optical excitation densities. For high fluences, significant induced absorption was observed. The recovery of this excited state absorption did not show as significant a dependence on the level of proton bombardment. It is possible that the cause of this induced absorption - carriers outside the InGaAs quantum wells, highly excited carriers, or those trapped in satellite valleys - is not sensitive to the effects of bombardment. Also, the bombardment-created defects may saturate at such high fluences. The detrimental side-effects of proton bombardment - reduced modulation depth and increased non-saturable loss - have been shown to be mitigated with a short post-growth anneal. Finally, modelocking was demonstrated with the proton-bombarded samples in an erbium fiber laser.

Carrier lifetime reduction resulting from proton bombardment of InGaAs/InP-based semiconductor saturable absorbers was studied experimentally, using a standard degenerate, cross-polarized pump-probe technique. Proton bombardment reduced carrier lifetimes by as much as a factor of 40 at low optical excitation densities. For high fluences, significant induced absorption was observed. The recovery of this excited state absorption did not show as significant a dependence on the level of proton bombardment. It is possible that the cause of this induced absorption - carriers outside the InGaAs quantum wells, highly excited carriers, or those trapped in satellite valleys - is not sensitive to the effects of bombardment. Also, the bombardment-created defects may saturate at such high fluences. The detrimental side-effects of proton bombardment - reduced modulation depth and increased non-saturable loss - have been shown to be mitigated with a short post-growth anneal. Finally, modelocking was demonstrated with the proton-bombarded samples in an erbium fiber laser.