  In this paper, we introduce an all-fibered dual-comb spectrometer based on a
new design of highly nonlinear fiber to efficiently convert frequency combs
from 1.55 micron to 2 micron We show that our spectrometer can be used to
measure absorption profiles of rovibrational transitions of CO2 and N2O
molecules, and especially their collisional self-broadening coefficients. The
results show very good agreement with the HITRAN database and thus further
measurements have been performed on a mixture CO2 /N2O to measure the
broadening of the CO2 absorption lines resulting from the presence of N2O.
