Uni-directional CWDM amplifier: installation example

Last updated on 02/16/2021

Eight-wavelength CWDM Amplifier

CWDM transmission enables low-cost WDM transmission using uncooled laser diodes. It is often the case that the eight long-wavelength channels, from 1471 to 1611 nm, are chosen. This is because the loss of silica optical fibers are lower than the other eight short-wavelength channles. The transmission distance is, still, typically limited up to 70km, and one reason is the lack of appropreate optical amplifiers in the S-band (i.e. 1471, 1491, 1511nm CWDM channels).

FiberLabs possesses S-band amplification technology enabled by in-house fluoride fiber. It allows us to produce a fiber amplifier working from 1471nm to 1611nm. Below is a schematic of how our CWDM booster amplifier AMP-FL5701-B8 is used in the uni-directional configuration. The link budget is increased by 10 dB by the addtion of the booster amplifier, extending the maximum transmission distance up to 130 km.

Increasing link budget using eight-wavelength CWDM booster amplifier

Figure 1: Increasing link budget using eight-wavelength CWDM booster amplifier

Booster and In-line Amplifier

In addition to the above configuration using a booster amplifier only, an in-line amplifier may be combined. Figure 2 schematically shows an CWDM tranmission scheme where our CWDM in-line amplifier AMP-FL5701-I8 is used combined with AMP-FL5701-B8. The transmission distance can be further increased by this addition.

Combination of booster and in-line amplifier

Figure 2: Combination of booster and in-line amplifier

Four-wavelengths CWDM Amplifier

If you do not need such a wide bandwidth using the eight wavelengths, it may be an option to use only the four long-wavelength channels, from 1531 to 1611 nm. Below is a schematic of how our four-wavelength CWDM booster amplifier AMP-FL5701-B4 and in-line amplifier AMP-FL5701-I4 are used in the uni-directional configuration.

Increasing link budget using four-wavelength CWDM amplifier

Figure 3: Increasing link budget using four-wavelength CWDM amplifier

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