Ion Laser Technology, 263 Jimmy Doolittle Road, reported earnings of $112,870 in the quarter ending Dec. 31 on revenue of $845,162, compared to earnings of $56,197 on revenue of $619,235 in the same quarter a year ago.

Lynn Barney, president of the company that manufactures argon and krypton lasers, said Ion earned $272,849 on revenue of $2.4 million in the last nine months of 1990, compared to earnings of $187,214 on revenue of $1.9 million in the same period a year ago.Barney said the company's working capital increased from $576,701 to $852,501 in the first three quarters of the fiscal year and now is 37.2 percent of total assets. The company's liquidity has allowed it to finance operations and growth without the use of bank debt.

Revenue and earnings growth are a result of increased sales of the company's new products along with the sale of equipment to China as part of the company's joint venture agreement with Shanghai, China.

As part of the agreement, Ion is training Chinese employees at its manufacturing facility in Salt Lake City. Completion of a manufacturing facility in Shanghai is scheduled for April 1991.