Wavelength change mechanism of light source SLD when starting up in fiber optic gyro

Simulation Study on Digital Control Model of Fiber Optic Gyro SLD Light Source

“…When SLD emits light, the spectrum consists of stimulated emission gain spectrum and spontaneous emission spectrum. According to the expression [9] of stimulated emission gain spectrum and spontaneous emission spectrum: SLD spectrum is related to injection current density, the higher the injection current, and the lower the central wavelength of spectrum. The average wavelength of SLD under different driving currents is measured by spectrometer, and the relationship between the average wavelength of SLD output and driving current is shown in Fig 2.…”

“…When a continuous driving current is applied to the SLD, the temperature in the active area of the SLD will rise due to the internal thermal effect, which will lead to a red shift in the output wavelength of the SLD [10]. The change of the output wavelength of the SLD with temperature can be approximately expressed by the following formula (1) [9]: In which 'h' is Planck constant; 'C' is the speed of light in vacuum; 'Eg' is the band gap of semiconductor materials used in SLD active Region. Generally speaking, 'Eg' changes with temperature, as shown in formula (2).…”

“…In the vicinity of room temperature, dEg/dT is approximated as a constant [9]. The relationship between the wavelength of SLD at 1310nm SLD temperature is fitted [9], and the specific result is shown in…”