Alcatel Optronics introduces non-reflecting version of FBG gain flattening filters

March 14, 2002--Alcatel Optronics (Paris: CGO et NASDAQ: ALAO) has introduced a new non-reflecting fiber Bragg grating (FBG) gain flattening filter (GFF), the Alcatel 1902 GFF, for use in WDM optical amplifiers for metro and long-haul networks. These filters allow manufacturers to reduce the size and cost of optical amplifiers.

The GFF filters are based on slanted Bragg gratings. To manufacture these optical filters, the grating is written at an angle on the fiber core. This slanted grating eliminates the reflected optical signal and reduces the ripple effect in the attenuation profile of the filter. The technology removes the need for optical isolators that are required when using reflective FBG gain-flattening filters.

The Alcatel 1902 GFF matches all the high-performance features of a regular FBG-based GFF filter. In addition, it provides a return loss of greater than 25 dB and reduces the spectral ripples by more than a factor of two. The slanted GFF is enclosed in a compact athermal package to minimize the temperature drifts in demanding applications and to guarantee that the attenuation profile is accurately maintained over the operating temperature range. The attenuation profile can cover C- or L-band with error functions down to +/- 0.1 dB, low insertion loss, low polarization dependent loss, and low polarization mode dispersion.