Tài liệu WDM Module Value-Added Module (VAM) System doc

By transmitting signals at different wavelengths through the same fiber, WDMs can multiply transmission capacity, improve testing, and transmit voice services over video.. Increasing Tra

Wavelength division multiplexing (WDM) remains the prevailing technology for adding flexibility and functionality to today’s optical networks By transmitting signals at different wavelengths through the same fiber, WDMs can multiply transmission capacity, improve testing, and transmit voice services over video Value-Added Module (VAM) systems equipped with WDM technology are used in a variety of applications to reduce operational expenses and increase revenue opportunities

Increasing Transmission Capacity

Fiber overlays can be expensive and time consuming In order to deliver broadband services, many service providers are integrating WDM modules into the network to gain capacity without deploying additional fiber

Adding a WDM on each end of a circuit instantly doubles the bandwidth on a fiber pair A typical application features one fiber for the transmit direction and another fiber for the receive direction (See Figure 1.) In most cases, legacy equipment will operate at 1310 nm It is simply a matter of incorporating a WDM module at each end of the span and adding new equipment transmitting at

1550 nm In a higher capacity network, transmission signals operating at 1310 nm and 1550 nm are then simultaneously transmitted over the same fibers (See Figure 2.) This enables the existing fiber in the plant to double capacity The WDM approach also enables providers to work with existing electronic equipment, which proves to be much more cost-effective than incorporating new DWDM modules or additional fibers into the network

Original Network

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1310 1310 Single Fiber

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Nonintrusive Testing

WDM modules introduce out-of-band testing by enabling networks to operate and test at different wavelengths A network operating at 1310 nm can be tested at 1550 nm and networks operating at 1550

nm can be tested at 1625 nm Out-of-band testing is a simple, effective solution that is easy to implement into the network (See Figure 3.)

Often, access to the customer or co-location site is restricted With WDMs, a signal at a different

wavelength from the normal traffic is injected at the near end of a system and travels to the far end, where

it is looped back via a WDM at the demarcation point and returns to the original end This allows full bi-directional OTDR (optical time domain reflectometer) testing on a live transmit/receive pair to be conducted from a central location The service provider reduces operational expenses by not rolling a truck to the far end or disrupting customer’s service for testing purposes

Figure 2 Higher Capacity Network with WDMs

1550

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Single Fiber 1550 1310

Figure 3 Continual Nonintrusive Testing

Single Fiber

Single Fiber 1550

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Figure 4

REAR FRONT

Connectorized Pigtail

Adapter Port

Adapter Port

OPTICAL COMPONENTS

Connectorized

Pigtail (3 mm Jacketed)

Bare Pigtail (2 mm Jacketed)

Transmitting Voice Services over Video

When video requirements arise, a WDM network offers a cost-competitive option compared to additional fiber deployment In most applications, a 1310 nm fiber route has already been established to

accommodate traditional voice grade service By using a 1550 nm video transmitter, both video and voice co-exist on the same fiber pairs, but are independently delivered to the subscriber

Value-Added Functionality

ADC’s plug-in VAM modules can be purchased with most industry standard singlemode connectors Module inputs and outputs can be made via adapter, pigtail or bare fiber depending on customer

requirements (See Figure 4.) Various combinations of all front access to input/output ports or rear access to both input/output ports are also available All bare fiber options use 2 mm jacketing

The variety of module configurations allows the provider the opportunity to determine the number and type of optical connections necessary depending on whether a cross-connect or interconnect arrangement

is used in the fiber cable management scheme

ADC Telecommunications, Inc., P.O Box 1101, Minneapolis, Minnesota USA 55440-1101

Specifications published here are current as of the date of publication of this document Because we are continuously improving our products, ADC reserves the right to change specifications without prior notice At any time, you may verify product specifications by contacting our headquarters office in Minneapolis ADC Telecommunications, Inc views its patent portfolio as an important corporate asset and vigorously enforces its patents Products or features contained herein may be covered by one or more U.S or foreign patents An Equal Opportunity Employer