Cutting High NA preforms

Hi All,

Has anyone ever attempted to cut a high NA fiber preform. I am talking
about
NA>0.20.

I know some people use a preform lathe itself to cut such preforms.
But I do not want tapered ends at the end of the cutting process. I am
thinking more in the lines of using a diamond tipped tool that could
do the job.

Any suggestions or ideas are welcome. Thank you.

max.