The winger has returned to Birmingham after spending the second half of the season on loan at Fratton Park.
Solomon-Otabor scored one goal in 10 appearances, although a calf injury he sustained in March sidelined him a short spell.
The 23-year-old has subsequently been offered a new one-year deal since going back to St Andrew’s.
Having been down the pecking order Birmingham before the turn of the year, Solomon-Otabor heaped praise on Kenny Jackett for recapturing his love for the game.
And he feels his stint at Pompey has made him mentally stronger.
Posting on Instagram, Solomon-Otabor wrote: ‘Thank you to @officialpompey for giving me an opportunity to come and play football and enjoy playing football again this season.
‘It has been full off ups and downs with injuries and disappointment but it made me mentally stronger and tougher as a person now it’s time to rest work hard in the off season and see what next for me in my career once again thank you to @officialpompey players staff and the fans.’