The effect of proton bombardment on semiconductor saturable absorber structure

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.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2000

Author dc:creator

• Gopinath, Juliet Tara, 1976-

Advisor dc:contributor.advisor

• Erich Ippen.

• Electrical Engineering and Computer Science.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/8808

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/8808