54 Keysight N777-C Series Tunable Laser Family User’s Guide
3 Definition of Terms
Measurement: Using the Lightwave signal analyzer, by analyzing the heterodyning
between the main signal and the highest side mode within 0.1 GHz to
6GHz.
Signal to source spontaneous emission (SSE) ratio
Specifies the ratio between signal power and maximum spontaneous
emission (SSE) power. The SSE power is determined in a specified
bandwidth within a ±3 nm window around the signal wavelength, where
±1 nm around the signal wavelength are excluded, expressed in dB per
specified bandwidth.
Figure 23 Signal to source spontaneous emission ratio.
Conditions: Output power as specified. Other conditions as specified.
Measurement: Using an optical spectrum analyzer (OSA) at 0.5 nm resolution bandwidth
(to address the possibility of higher SSE within a narrower bandwidth),
then extrapolated to 1 nm bandwidth. For the low-SSE output, if
applicable, with a fiber Bragg grating inserted between the tunable laser
source and the OSA to suppress the signal, thereby enhancing the
dynamic range of the OSA.