Apple could be headed for slower growth and its impressive earnings reports could become a thing of the past, if one analyst's predictions are correct.

A top technology analyst said that Apple will not be growing at double-digit numbers like competitors Amazon and Alphabet (Google), CNBC reports.

"The fear is that Apple is entering growth purgatory," senior analyst Toni Sacconaghi of Sanford C. Bernstein said Tuesday on CNBC's "Halftime Report."

"It had the great last cycle with the iPhone 6. The fear is smartphones are in an increasingly mature marketplace, particularly at the high end. That's almost all of Apple's earnings and growth."  

Apple has relied on its smartphone the iPhone to keep its profits up, but Sacconaghi says the company will have trouble continuing to remain competitive in the smartphone market. Apple will have to rely on its other projects like the Apple TV, the Apple Watch and a rumored self-driving car to keep its revenue up.

"You'd have to believe that the car would kick in, and drive revenues," Sacconaghi said.

"Or that the watch would ultimately be something very big. But I think investors are worried about the next two-year period. Can there really be iPhone growth?" 

Apple and its partners have been watching the reports of sales of the new iPhone very closely. Apple reported its earning numbers after the closing bell on Tuesday, and iPhone 6s sales were 48.04 million units in the fiscal fourth quarter.

Analysts had expected 48 million units of the iPhone 6s to be sold meaning sales of $31.37 billion for the phone. Overall Apple reported earnings per share of $1.96 on revenue of $51.5 billion.

Apple has been able to sell a great deal of iPhone 6s units to Chinese customers, and that has helped their growth as well.

Apple has a new iPad coming out soon, the iPad Pro, and several other gadget updates could debut in the near future.