young couple
Refers to a married couple who are young in age, or sometimes to a newlywed couple.
The young couple who moved in next door are very pleasant.
That young couple goes jogging together every morning.
老夫婦 describes a married couple who are both elderly, while 若夫婦 refers to a young married couple.
Compound of 若 (waka, 'young') and 夫婦 (fūfu, 'married couple').