1. The transponder accepts input in the form of a standard single-mode or multimode laser pulse. The input can come from different physical media and different protocols and traffic types.
2. The wavelength of the transponder input signal is mapped to a DWDM wavelength.
3. DWDM wavelengths from the transponder are multiplexed with signals from the direct interface to form a composite optical signal which is launched into the fiber.
4. A post-amplifier (booster amplifier) boosts the strength of the optical signal as it leaves the multiplexer.
5. An OADM is used at a remote location to drop and add bitstreams of a specific wavelength.
6. Additional optical amplifiers can be used along the fiber span (in-line amplifier) as needed.
7. A pre-amplifier boosts the signal before it enters the demultiplexer.
8. The incoming signal is demultiplexed into individual DWDM wavelengths.
9. The individual DWDM lambdas are either mapped to the required output type through the transponder or they are passed directly to client-side equipment.
