single-mode and multi-mode laser diodes

[Videogamer555]

Generally speaking though, the oval produced by a singlemode diode is "close enough" to TEM00...

Wait I thought that multimode produced the oval beam, and the singlemode produced the circular beam.

 

[ElektroFreak]

No. Single-mode produces an oval, multimode produces a line or a tight square cluster of spots depending on the type of diode.

Examples found randomly on the web:

Singlemode:

Multimode:

You can see that the multimode profile is both wider and flatter, but it is also made up of multiple hot areas, hence the name "multimode".