NEW YORK, Dec. 10 -- JDS Uniphase Corp. has reiterated previous sales guidance for the second fiscal quarter and added that sales in the March quarter could fall a further 15 percent. The company said it expects that to be the low point in the current downturn. JDS said sales in the ongoing quarter will be between $296.1 million and $279.75 million, or 10 to 15 percent off those of the first fiscal quarter. JDS, which has almost halved its work force to keep pace with sliding demand, on Oct. 25 posted plunging first-quarter losses.