Unintentional Oscillation on Spectrum & raw_data_read problem

[LeAmarillo]

Hi all! I met some problems when using QE65000 to obtain the spectrum.

The spectrometer I use is QE65000. The light source is a halogen hl-2000 tungsten lamp. It is from a simple light source test. I was measuring the spectrum of the hl-2000 by aligning the collimators of 2 fibers connected to the lamp and the spectrometer separately.

Here is the spectrum I got.

It is easy to observe the oscillation starting from around 700nm.

Not sure what caused the problem. My primary guess is the correction issue. The raw intensity data generated by the spectrometer may be corrected by some coefficients before being read by the software. So I tried to get the data w/ & w.o./ dark counts and nonlinearity. Here is the code to generate the spectrum above. (I get used to Matlab so it is executed in Matlab)

import py.seabreeze.*;
spectro = py.seabreeze.spectrometers.Spectrometer.from_first_available;

spectro.f.thermo_electric.enable_tec(1);
spectro.f.thermo_electric.set_temperature_setpoint_degrees_celsius(-5);

I1 = double(spectro.intensities(0,0));
I2 = double(spectro.intensities(0,1));
I3 = double(spectro.intensities(1,0));
I4 = double(spectro.intensities(1,1));

plot(wave,I1,wave,I2,wave,I3,wave,I4,LineWidth=1);
legend('I1','I2','I3','I4');

The oscillation problem still exists no matter whether it is corrected. I tried to use the function raw_data_read('secondary_in',16) but it kept running for a very long time.

Has anyone met this kind of problem? Does anyone have any idea why it is and how to deal with the oscillation? Thanks!

P.S. I think it should not be the problem caused by the light source. With USB4000, I got a reasonable spectrum for the same lamp.