[Opt. Soc. America Technical Digest Summaries of papers presented at the International Quantum Electronics Conference Conference Edition. 1998 Technical Digest Series, Vol.7 - San Francisco, CA, USA (3-8 May 1998)] Technical Digest. Summaries of Papers Presented at the International Quantum Electronics Conference. Conference Edition. 1998 Technical Digest Series, Vol.7 (IEEE Cat. No.98CH36236) - Ultrafast coherent response of semiconductor quantum wells for multisubband excitation