Is There a Q Factor for DBRs?

[Gen1111]

Some people use Q factor as a measure of the quality of a distributed Bragg reflector (DBR) which doesn't make much sense to me.
I understand that the Q factor is a measure of how slw a resonator looses it's stored energy.
However, I don't think DBRs store energy in a similar way to springs or other oscillators.

I more or less understand what the Q factor of an optical cavity between two DBR means.
The cavity stores energy by confining light between the two DBRs, and if the Q factor is high the field intensity will take a long time to decay.
This is consistent to the definitions of Q factor.
Is there such thing as a Q factor of a DBR or is it just a mistake?

 

[MisterX]

I'm not an expert in DBRs, but I don't think you need to make an analogy to an oscillator to have a meaningful Q-factor.

Q factor could be the ratio of the central frequency over the difference between the half-power (-3dB) frequencies. It is a measure of sharpness.

But I suppose one could use this concept for any function with a central peak. Maybe you should ask to learn exactly what definition they are using.

 

[sophiecentaur]

Q factor is probably more useful as a measure of bandwidth because it's independent of frequency and doesn't need a % sign. In the case of a laser it's probably pretty high.