What the company claims to be the first MEMS-based dynamic gain equalizer (DGE) for long haul and ultra long haul dense wavelength division multiplexing (DWDM) systems was announced by LIGHTCONNECT, Inc. Formed in 1999, LIGHTCONNECT designs and manufactures innovative, dynamic MEMS-based fiber optic components for next generation, dynamically configurable optical networks.
The LIGHTCONNECT DGE1020, when used in a feedback loop, dynamically compensates amplifier gain profiles, thus enabling high signal-to-noise ratio for all channels in optical amplifier systems. Dynamic gain compensation improves system performance, increases system flexibility and increases the distance between amplifiers in long haul and ultra long haul transmission systems. This device is intended for use with Erbium-doped fiber amplifiers and Raman amplifiers.
The DGE1020 is based on diffractive MEMS (D-MEMS) technology that offers several advantages over other MEMS technology. Unlike mirror-based MEMS devices that require large movements of small mirrors, the diffractive MEMS approach requires motion less than 0.4 microns. Moreover, the high resonant frequencies of the D-MEMS ribbons increase speed by 50 to 500 times over mirror based MEMS components while providing a robust optical platform which is virtually unaffected by ambient acoustic and seismic disturbances.
Existing static gain flattening filters are incapable of responding to changes in optical networks, thus preventing continuous optimum system performance. Diffractive MEMS-based DGEs, on the other hand, respond rapidly and with excellent wavelength resolution to changes in the optical amplifier gain profile, with consequent low residual ripple after equalization even in the steepest portions of the gain profile. The D-MEMS-based DGEs consume little power, require no temperature control, and have a small package size (64 x 96 x 16mm).
Features of the DGE1020:
* Operating Wavelength Range: 1528nm - 1570 nm
* Wavelength Step Response: 15 db in 4 nm
* Maximum Attenuation: 15 db
* Insertion loss: <6 db
*Polarization Dependent Loss: <0.25 db
* Residual ripple: <0.30 db
* Speed: <50 microseconds
To maximize the signal to noise of an optically amplified system, nonlinear effects in the optical fiber make it necessary to maintain approximately equal power in the optical channels of a DWDM system. The greatest contributor to the unbalancing of the channels is the optical amplifier's gain profile. Moreover after passing through several cascaded amplifiers, the effect is compounded and the different channels can have quite different powers. This is a serious problem in long haul and ultra long haul transmission systems where a signal might pass through several dozen amplifiers.
To compensate for this unbalancing in current fiber optic communication systems, a static optical filter is placed after each amplifier. However, static gain equalization is impossible if the amplifier gain profile is changing with time as it does in dynamically reconfigurable optical networks.
A solution is to use an optical filter that can dynamically adapt itself to the changing needs of the system. In this way the maximum data rate can be maintained continuously. A dynamic gain equalizer, or DGE, is just such a device. A DGE provides an electronically programmable continuous wavelength dependent attenuation to adjust all of the channels simultaneously.
The LIGHTCONNECT DGE1020 is priced at $16,000 in sample qualities, with volume discounts. An L-band version will be available in the fall of 2001.
About LIGHTCONNECT, Inc.:
Founded in 1999, LIGHTCONNECT designs and manufactures innovative, MEMS-based, fiber optic components for next generation, dynamically configurable optical networks. For more information, visit www.lightconnect.com.