(Greg Hennessy) wrote in news:d1d401$7ns$1
@tantalus.no-ip.org:

In article ,
John Schutkeker wrote:
If someone can repeat the question (I only see replies, not the head
article) I can try to answer the question. I am an employee of USNO.

I wanted to build an optical imaging interferometer that worked over a
phone line.

How were you planning on downconverting the terahertz frequency
optical frequencies to a bandwidth a phone line could handle?

I'm not a heterodyne savant, but somebody told me that lasers might do it,
although I'm still open to suggestions. Perhaps you could have a staged
system, where you step it down once or twice by several dB using different
methods. HeNe's would be great, because they're also dirt cheap.

I'm willing to sacrifice bandwidth for twisted pair (or shielded twisted
pair) because the heart of the idea is to gain distance (which translates
to aperture size) cheaply.