Arrange the following real numbers in ascending order:
$$\frac{2}{\sqrt{2}},1.41,1.4142,1.414$$

Let's convert all values to uniform decimal expansions to compare them precisely:
1. $1.41=1.41000\dots$
2. $1.414=1.41400\dots$
3. $1.4142=1.41420\dots$
4. $\frac{2}{\sqrt{2}}=\frac{\sqrt{2}\times \sqrt{2}}{\sqrt{2}}=\sqrt{2}\approx 1.41421356\dots$

Comparing the decimal expansion places from left to right:

$$1.41000<1.41400<1.41420<1.41421\dots$$

$$1.41<1.414<1.4142<\frac{2}{\sqrt{2}}$$

This matches option D.