Dear Editor,

again, we would like to thank the reviewer for the time spent with the
manuscript.
 The main critique of remains a concern of adequate novelty of our work in
comparison with the one reported in Medea et al. (2016). We do believe that
our work goes beyond confirmation of their findings, as we provide a better
spectral resolution, and also present a method that allows to characterize the
breakdown flash for a particular set of InGaAs APD that is easier to carry
out, as our method does not require pulsed laser systems in comparison with
the Medea work. Ultimately, every QKD system will have to document that this
side channel is not a problem, and a simpler testing method is very important
for such a purpose.
Therefore, we would disagree with the referee's view that our work has very
little to report.

 We did consider to give more credit to the Medea et al. work by pointing out
in our conclusion that their conclusion  is similar to ours.

As for the pre-production review comments, we could not find any references to
figures that were wrongly put in parentheses, and that our use of parentheses
complies with the stipulated use for referencing sub-figures. We also
referenced all funding sources.


The summary of changes in this second revision:

1. We added an additional reference to the work of Medea et al. to the end of
the second sentence in the last paragraph of the conclusion: "...information
leakage through the breakdown flash in a quantum key distribution scenario,
similar to findings in [18]." to emphasize their findings for InGaAs
photodiodes.

2. We amended a reference to figure 2 in the 7th paragraph of section 2 now to
refer to figure 2(b) instead of figure 2 only:
"The events timing histogram is shown in Fig. 2(b)."

In summary, we hope to have addressed the concerns of the referee, and look
forward for a consideration of publication in Optics Express.