According to a report by the US tech blog AppleInsider, documents submitted by Apple Inc. to the Securities and Exchange Commission (SEC) show that this year the company's R&D related expenses will increase by 33% year-on-year, exceeding $4 billion for the entire fiscal year of 2013.In the quarter ended March 31, Apple's added R&D expenses were $278 million, an increase of 33% compared to the same period last year. For the first half of the fiscal year 2013, Apple's added R&D expenses were $530 million, also increasing by 33% year-on-year. At this growth rate, Apple's added R&D expenses for the entire year will exceed $1 billion.In the documents submitted to the SEC, Apple stated that the increase in R&D expenses was due to the growth in personnel and related costs to support the expansion of R&D activities. Apple believes that such cost expenditures are crucial for future development, and the company will continue to invest in R&D.At the current growth rate, it will be easy for Apple's total R&D expenses for this fiscal year to exceed $4 billion, while they were $3.4 billion in fiscal year 2012. In the past few years, Apple's R&D expenses have continued to grow, with an increase of $953 million year-on-year just last year, representing a 39% increase.Despite the rapid growth in Apple's R&D expenditure, it is still only a small portion relative to the cash held by the company. As of the end of the last quarter, Apple held nearly $145 billion in cash. Therefore, Apple has decided to return $100 billion to shareholders through stock buybacks and dividends by the end of 2015.There is no doubt that the development of new products is the main driver of profit growth for Apple, which is why people are curious about what products Apple is developing. Since the release of the iPad mini last October, Apple has not released any major new products.Apple is expected to release new versions of the iPhone, iPad, and Mac computers this autumn, but some industry insiders speculate that the company may be developing entirely new types of products, entering new fields. Rumored products include a low-cost version of the iPhone, a television, and a smartwatch.Apple CEO Tim Cook stated during Tuesday's earnings call that the company is developing many surprising products. Additionally, Apple plans to launch new types of devices and services. This statement goes against Apple's usual tradition of secrecy.