A new tenant is coming to an empty Columbia office building that last housed a fiber-optics company that had promised to hire 1,000 workers but fizzled out in less than two years.

Corporate Office Properties Trust declined yesterday to identify the new tenant for 9140 Route 108, but a government source said another U.S. government user planned to move in.

The government is the biggest tenant for Columbia-based COPT, one of the largest office landlords in the Baltimore-Washington corridor.

Randall M. Griffin, president and chief executive, said he was pleased to lease the building so quickly in a down market.

Bookham Technology PLC, a British fiber-optics company, said in July that it would close its North American headquarters by September and lay off about 45 people.

"There were others looking at the building," said Griffin. "We were able to get a tenant who signed a long-term lease. We improved our situation without putting any money into the building."

Griffin said most of the Bookham workers are gone from the 150,000-square-foot building in Oakland Ridge Industrial Park. Bookham recently auctioned its equipment, and a spokesman for the company said the new tenant had allowed it to dissolve a long-term lease.

He has said this year that defense contracting and work related to the National Security Agency would provide an opportunity for COPT buildings.

In announcing third-quarter results, Griffin said in a statement: "The bulk of our leasing activity continues to be driven by the increasing demand from the defense and intelligence sectors. These sectors now account for 36 percent of our total revenues, up from 26 percent at the beginning of the year. ... In addition to the U.S. government, the demand for office space by defense contractors, stemming from the events of 9/11 is now beginning to be felt in the marketplace. Our biggest challenge over the next year will be moving expeditiously to accommodate this demand through a combination of tenant relocations and development."

The new lease in the two-story building should help Columbia, which was hit by the economic slowdown in general and the technology bust specifically.

Many of the region's technology companies are in the corridor and have scaled back, including fiber-optic maker Corvis Corp. Trellis Photonics Ltd., an Israeli start-up that moved its headquarters to Columbia, never hired more than 14 employees and closed its U.S. operations last year.

The COPT building, which includes manufacturing space, is considered "flex" space that can be used for a variety of purposes. It is often used by tech companies that need offices and research and development space.

Vacancy among flex buildings in the corridor is about 9.8 percent, compared with about 11.4 percent for the region, said MacKenzie/Oncor International, a commercial real estate firm.

The new tenant's lease begins in January, COPT said.

Howard County and state economic development officials said they did not assist COPT and did not know the tenant.

Officials at the General Services Administration, responsible for leasing buildings for the federal government, were not available to comment.