FiberLabs Inc

Unvailing 23-dBm O-band PDFA prototype

Last updated on 04/24/2021


Now the prototype shown in this post has been released as AMP-FL8612-OB-23. Please refer to the following link for product details.

O-band amplifier (PDFA, bench-top type)

This post is kept here as a record of our R&D activity.


FiberLabs’ PDFAs have been a popular choice for amplifying 100G/400G Ethernet signal in the O-band, particularly useful for transceiver testing (see example), as well as network monitoring and reach extension. Currently our high-end model is FL-AMP8611-OB-20, and we always hear strong demands for a higher output power.

We are now ready to unvail a “prototype” of our higher-power PDFA FL-AMP8612-OB, targeting to double the output power. This post provides basic amplification characteristics of the prototype.

Test Setup

Test setup

Figure 1: Test setup.

The setup of the experiment is shown in Fig. 1. The input signal (0 dBm at 1310 nm) was provided by FiberLabs TLS-FL-O tunable laser. The input signal was amplified in the prototype amplifier, and the output signal was measured by a power meter and optical spectrum analyzer. The size of the amplifier chassis is the same as FL-AMP8611-OB-20.

Amplification characteristics at 1310 nm

The graph shown in Fig. 2 is the measured output power with regard to the pump current (normalized to maximum available). This prototype amplifier provided maxium 350 mW (>25 dBm), which is limited by available pump power.

Output power at 1310 nm

Figure 2: Output power at 1310 nm.

The output spectra (at +23- and +25-dBm output power) are shown in Figs. 3 and 4. The amplifier provided a clean spectrum with no onset of unstable behavior.

Output spectrum at +23-dBm output

Figure 3: Output spectrum at +23-dBm output.

Output spectrum at +25-dBm output

Figure 4: Output spectrum at +25-dBm output.

Next step

We are excited to get an output power much higher than our 23-dBm target, however, this is a preliminary result and additional tests should be done before product release.

We plan to start more thorough testing – for example, gain measurement at 400GBASE-LR8/ER8 and CWDM4 wavelengths. This amplifier should provide a higher gain at these wavelengths, and thus it may allow us to produce a flat-gain O-band amplifier with the incorporation of a gain-flattening filter inside.

We appreciate your input!

If you are a potential customer interested in using this amplifier, we appreciate your input in order to make our product better. Please send us your requests via request sheet!

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