Agere Systems, formerly known as the Microelectronics Group of Lucent Technologies (NYSE: LU), announced a dynamic gain equalization filter (DGEF) module that can be used to enhance the performance of optical amplifiers in ultra-long-haul dense wavelength division multiplexing (DWDM) systems.
The DGEF module improves the signal-to-noise ratio in optically amplified systems and increases the distance between amplifiers. The DGEF contains the microprocessor-controlled electronics necessary to perform real-time gain management in a network. This module is the first in a planned family of planar lightwave circuit devices announced by Agere Systems.
DGEFs are positioned at interstage access points and can be used in new or existing optical networks to correct for nonlinearities in long amplified optical spans. Agere's DGEF module sits alongside an amplifier -- such as an erbium-doped fiber amplifier (EDFA) or Raman amplifier -- and uses a microprocessor-controlled silica waveguide (SiWG) to attenuate the entire C- or L-band. The DGEF is a band equalizer, so it does not impact the channel width in a DWDM system and utilizes any channel plan from 50-200 gigahertz channel spacings.
The DGEF module is an improvement over the fixed gain flattening filters (GFFs) found inside EDFAs because it allows system manufacturers to dynamically control gain in real time based on system fluctuations. The DGEF technology - pioneered by Bell Labs, Lucent's R&D arm -- is developed using silica waveguide wafer fabrication, which can enable high levels of integration on one silicon substrate. These planar lightwave circuits can serve as a platform to monolithically incorporate dynamic filters and optical switches, as well as integrate active and passive components. Silica waveguides are built on an existing manufacturing platform that has significant synergies with integrated circuit wafer fabrication, and is amenable to low-cost, volume production.
The DGEF modules will be the first products designed and manufactured using Agere Systems' new planar lightwave circuits operations in Allentown, Pa. The Allentown facility recently expanded an existing integrated circuits wafer fab to meet demand for this technology and offer high-volume manufacturing capabilities for planar lightwave circuits.
Samples of the DGEF module are expected to be available to customers in the second calendar quarter of 2001, with production quantities in the fourth calendar quarter.
Also announced, Agere Systems is offering a new Raman pump module, which is compatible with this DGEF solution. The L-band Raman pump module for high-speed optical transmission systems combines passive optical components and multiple pump lasers in the same package. The module is designed for use with erbium-doped fiber amplifiers (EDFAs) to improve signal performance and lengthen transmission distances between repeaters. Based on Agere Systems' expertise in amplifier and pump laser technology, the module can be customized to accommodate diverse system requirements in new or existing optical networking systems.
The Raman pump module can be implemented externally to an existing EDFA or it can be physically integrated as part of the pre-amplifier section of an EDFA. Raman amplification improves on EDFA performance by reducing the noise figure, offering a flexible gain profile and enhancing gain flatness. These attributes enable higher channel counts, faster transmission speeds and longer distances between regeneration sites for system manufacturers.
Agere Systems offers a broad range of technologies to support Raman amplification. At the heart of the Raman module are 14xx nanometer (nm) pump lasers, which provide the high optical power needed to achieve signal amplification within the transmission fiber. Agere Systems has a long and successful history of developing and manufacturing high-powered indium-phosphide (InP) lasers, including 14xx nm pump lasers for terrestrial and submarine applications, based on innovations from Bell Labs, Lucent's R&D arm.
In addition to pump lasers, the module also includes a range of passive components -- including taps, isolators and combiners -- required for multiple functions within optical amplifiers. Critical to these passive components are thin-film filters, which enable wavelength management functions such as separation and combination. Agere Systems develops and manufactures these filters in-house using the staff, facilities and technology acquired last year from Herrmann Technology. When combined with its automation platform for laser manufacturing, Agere will be able to offer customers integrated, tailored Raman pump modules.
Samples of the Raman pump module are expected to be available to customers in the second calendar quarter of 2001, with production quantities in the third calendar quarter. In addition to L-band modules, units in C-band will also be available.
Both products will be featured in a combined active demonstration at this year's Optical Fiber Communication conference in Anaheim, Calif., being held March 19-21.
About Agere Systems:
Agere Systems Inc., formerly known as the Microelectronics Group of Lucent Technologies, is a provider of semiconductors for communications applications. Agere Systems offers integrated optoelectronics and integrated circuit solutions to help customers reduce the time and expense of developing new communications equipment. For more information, visit www.agere.com.