Introduction

We have released high power O-band amplifier (+23 dBm (200 mW) PDFA FL-AMP8612-OB-23), and reported that it is able to achieve higher output power of > +26 dBm (> 400 mW) at around 1300 nm. This high-power O-band amplifier has potential to create new avenues of research and expand applications in optical communication, bio-imaging and other fields.

In this report, we inform that the high power PDFA has realized long-term stable operation over 100 hours with output power of 500 mW.

Output power evolution

The internal configuration of the PDFA used in the test was slightly tuned from the AMP-FL8612-OB-23, though there are no differences on the component level. This tuning was made in order to produce a higher output power (500 mW at 1310 nm) with the same pump power as the OB-23. This allows us to conduct a high-power endurance test at 500 mW, using the same optical components.

A 40-mW seed light at 1310 nm from a DFB-LD was amplified by the high power PDFA, and the output signal was measured by a power meter.

Figure 1: Schematic of test setup.

Fig.2 shows the output power evolution as a function of pump current normalized by the maximum available. Output power of more than 500 mW (27 dBm) was achieved, which was limited by available pump power. To the best of our knowledge, this is the highest output power from rare-earth doped fiber light sources at 1310 nm. Also, further power scaling would be realized by using a more powerful pumping source

Figure 2: Output power evolution at 1310 nm.

High-power long-term operation

Fig.2 shows a long-term temporal variation of the output power from the PDFA, showing the 500-mW output level was maintained over 100 hours. We repeated this test several times and no sign of degradation was observed.

Figure 3: Temporal variation of the output power from the PDFA.

Next step

We plan to test high power operation at other signal wavelengths such as 1290 nm and 1330 nm, which is significantly important for 400GBASE-LR8 and CWDM4. We believe that our high power PDFA opens new opportunities in optical communication technology, biological science, and frequency conversion.