Why do we need wavesplitters?

[neskusen]

I think I have the correct info, but please review and correct me if I'm wrong.

We can imply rotate a laser diode 90 degrees and not use a wavesplitter before a PBS combining cube, but then we wouldn't be able to use correction optics on the rotated diode beam properly as the slow axis would be flipped. Am I correct, is this the reason?

[LaNeK779]

you can use corrective optics on each diode separately BEFORE the pbs, but this is much much more expensive that using a waveplate
most important is that, depending on diode divergence, you will end up with a huge + instead of a dot

you really need to get your hands on a couple of diodes and start experimenting, things will become much clearer

[neskusen]

depending on diode divergence, you will end up with a huge + instead of a dot

Yeah that's what I meant. Thanks for confirming this.

As for getting diodes and testing, for sure. Although I don't see how I could confirm I'm not missing something by simply testing it. Not everything becomes clear from a test, plus you can come to the wrong conclusion by not noticing or knowing some other variable involved in a test, wouldn't you agree?