We closed the major follow-on order for our first betting customer that employees are differentiated thermoelectric solution at the core of its product and experienced increased demand for our thermoelectric products from multiple life science customers who placed significant replacement orders. Bookings in our Military business increased sequentially. We are pleased to announce that a significant long-term contract was received in the quarter for sapphire windows. The initial sapphire window order for $11 million is the first release against this multi-year contract valued at approximately $36 million . The revenue decrease year-over-year and sequentially was driven by a combination of factors.
These include lower defense spending in our Military business, lower rare-earth element sales and significantly reduced shipments in our ceramic silicon carbide semiconductor equipment business. However, we continue to be very encouraged by the strong growth and demand for our 150 millimeter silicon carbide products, which we believe will be a key driver to enable market share growth in major commercial markets for a silicon carbide-based electronic devices. To address the growth in the semiconductor substrate demand, we are nearing completion of major infrastructure expansion of our fiscal growth capacity. In an effort to offset the impact of the slowdown in the semiconductor equipment business, we have diversified our silicon carbide ceramics business and achieved several new product design wins among back-end semiconductor tool suppliers, where precision motion control applications are increasing.
We are now servicing customers in the back-end of the semiconductor [INAUDIBLE]with robotic end effectors, vacuum trucks and thermal transfer components. In addition, we continue to see increased demand in our silicon carbide display business driven by GA-LCD television production in Korea and China. In our Military business, we continue to execute a plan to consolidate our California and Florida operations due to lower market demand, and we are on track to complete these activities in our fiscal fourth quarter. While Military bookings were up from the prior quarter, the outlook for the Military market still remains uncertain and continued program delays are expected. Lastly, in our Performance Metals division, the core business remains stable under the new operating model and has a solid order backlog for the next several quarters. I will now turn it over to Mary Jane, to walk us through a review of our overall financial performance. Mary Jane?
Mary Jane Raymond – Chief Financial Officer
Thank you, Chuck, and thanks, Fran. For the second quarter, our Book to Bill ratio was 1.06. Our backlog is $228 million, compared to $218 million last quarter, the first fiscal quarter of the year.This $228 million consists of $73 million in Laser Solutions, $54 million in Photonics, and$101 million in Performance Products. The gross margin of 35.7% declined 80 basis points compared to the first quarter, but improved $460 basis points compared to the second quarter of last fiscal year. The year-over-year margin increase is a combination of general operating improvements in the recent acquisitions in particular and not having the one-time inventory step-up recorded in last year’s second quarter.
The operating margin of 9.3% declined from Q1 by 110 basis points, but improved by 370 basis points over last year’s quarter. This also is affected most importantly by operating improvements, as well as the absence of the inventory step-up last year. The adjusted EBITDA margin, which excludes the income from the settlement we noted improved 80 basis points over Q1 and 290 basis points over a year ago quarter. The GAAP EPS of$0.35 included a $0.11 on the settlement we noted. This settlement is related to certain payment obligations we had in the purchase agreement for the acquisitions we did last year.
