DWDM: New Way to Build Networks

David Devereaux-Weber

Definition

• Dense Wavelength Division Multiplexing permits multiple optical signals to travel on the same fiber at different optical wavelengths

How Do We Use DWDM?

• Purchase right to use (Indefeasible Right to Use or IRU) someone else's dark fiber - they maintain the jacket and own the fibers, you use the fiber.

• Install your own fiber – you maintain the jacket and use the fiber.

Why Use DWDM?

• In high-bandwidth situations, using DWDM saves cost compared to using multiple fiber pairs.

• Using optical amplification can extend the reach of an optical span, reducing or eliminating the need for electrical regeneration.

Further DWDM Savings

• Optical amplification can carry more than one optical bandwidth, sharing the cost of amplification over multiple circuits.

Dim Fiber

• In the dark fiber situation, you have access to the entire fiber and all the wavelengths it can carry; you furnish the DWDM equipment and the transport equipment for each wavelength.

• If you only need one optical wavelength, the carrier owns the DWDM equipment, furnishes dim fiber to you

Telecom Paradigm Shifts

• Carriers moving from tariffed to non-tariffed services.

• Price can drop more in non-tariffed environment.

• Changing from circuit provider to fiber caretaker

Datacom Paradigm Shifts

• Reducing intermediate layers, like ATM, Frame Relay or SONET.

• Reducing provisioning complexity