'Two weeks later' or 'In two weeks'

[tulipflower]

Can we use the following structure to express future tense?

'Two weeks later'

I'll call you two weeks later.

 

[tedmc]

No.
I'll call you in two weeks' time.

 

[5jj]

Also: I'll call you in two weeks.

 

[Phaedrus]

Can we use the following structure to express future tense?

'Two weeks later'

I'll call you two weeks later.

Yes. For example:

I'll see you in a week. Two weeks later, I'll call you.

In the context of that sentence pair, "two weeks later" means two weeks after the speaker sees the interlocutor, i.e., three weeks from today.