NCM-1550-EM30 (1550nm externally modulated optical transmitter) operating manual
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3.4.7
Frequency Adjust ITU in DWDM
To help DWDM applications, NCM-1550-EM30 can adjust optical wavelength. The
adjustable range is ±100GHz, 50GHz stepping. The button on the front panel or the
Ethernet interface will complete the adjustment.
λ=c/f, c is the speed of light. It is the constant value.
c=299792458m/s,
f is the frequency, its unit is Hz; eg frequency 193400GHZ, the
corresponding wavelength is 1550.12nm.
In the 1545-1560nm band, the frequency distance and the wavelength distance is very
similar to linear relationship.
50GHz frequency distance reflects to wavelength is very approximate to 0.4nm width;
As the same, 100GHz frequency distance reflects to wavelength is very approximate
to 0.8nm width.
3.4.8
SBS Suppression Adjustment
SBS value is very important in 1550nm long-distance transmission system. Stable
continuous coherent light source, add +6 dBm optical power in the standard single
mode fiber may occur SBS phenomenon. Ultrahigh SBS threshold will reduce CNR
and CSO low-frequency indicators.
High SBS threshold will also influence self phase modulation (SPM) and reduce
high-frequency CSO indicator.
When meet the conditions, as far as possible to use a low threshold SBS.
