Can you briefly talk about fiber grating technology and pre-chirp technology? . . . . This is for defense. Please kneel down. . . .

You pay attention to these two dispersion compensation technologies.

The dispersion compensation of fiber grating is to use the reflection of different wavelengths in different areas of the grating to make the optical signal have a long optical path at the leading edge and a short optical path at the trailing edge, so as to compress the signal and realize dispersion compensation.

Pre-chirp means that the signal is pre-deformed by some special modulation before transmission. Usually, the signal pulse is compressed and deformed, so that the signal will return to its normal shape after a certain distance of transmission, and will be widened after further transmission, but the transmission distance can be extended because the signal reaches its normal shape after a period of transmission.