Power Classes
One of the most critical decisions in deploying modern coherent optics is selecting the correct transmit output power. This generally splits into Standard Power (-10 dBm) and High Power (or "Bright", 0 dBm) variants.
In modern deployments (Greenfield), a new DCI link from scratch, operators often use simple point-to-point systems. These systems are designed to accept the lower power standard of OIF ZR (-10 dBm). Because the entire link is new, the line system amplifiers are engineered to handle this lower input signal.
Most telecom service providers have existing ROADM networks (Brownfield or legacy networks) that were built for older transponders. These legacy networks typically expect input signals at 0 dBm.
Standard Power Optics (-10 dBm)
These modules focus on power efficiency and cost. By omitting a high-power booster amplifier, they keep the module's power consumption lower (typically <20W for 400G). If you plug a -10 dBm module into a legacy ROADM expecting 0 dBm, the signal will be too weak. The ROADM's amplifiers may introduce excessive noise (ASE) when trying to boost this weak signal, resulting in a severe OSNR penalty. In many cases, the link simply won't come up.
Using these in brownfield networks requires external amplification (e.g., an external EDFA chassis) before the signal enters the ROADM. This adds rack space, cost, and complexity thereby negating the benefits of IPoDWDM.
Use standard power optics if you’re building a short point-to-point link (DCI) or have a modern open line system explicitly designed for ZR optics.
High Power (Bright) Optics (0 dBm)
These modules integrate a miniaturized EDFA or Semiconductor Optical Amplifier (SOA) directly inside the pluggable transceiver. They output signal at 0 dBm to +1 dBm that allows them to match the power levels of existing 10G and 100G wavelengths on the optical fiber.
You can plug a high power optical transceiver directly into a router port and patch it into an existing ROADM add/drop port. The ROADM sees it as just another valid 0 dBm signal enabling operators to upgrade capacity without overhauling their optical line systems.
Use high power optics if you are traversing a ROADM network, integrating with legacy telecom infrastructure, or need the extra optical budget to span longer distances without amplification.