I don't understand how we can produce a laser system with different (lower) repetition rate than the resonant frequency of the cavity?
In other words, when we have different resonating modes, then isn't it that the separation frequency is always
c/2L, where L is the distance between the two mirrors (
λ = 2L).
So, in other words, let's say if we have a wavelength of
λ=1550 nm, then
f=c/λ then the frequency of
1550 nm light to be
So, in other words, the separation frequency of the modes will be
f=193 THz. Then how can we generate pulses at a repetition rate equal to the bit rate B?
The bit rate (B) is real applications could be way lower than the separation frequency. Imagine that our data rate is only
5 Gbps, then how are we going to produce pulses at that (relatively slower) rate, knowing that inside the cavity, the repetition rate (in this example) is very high @
f=193 THz? (since this is what the resonant frequency is).
How can cavity produces repetition pulses way slower than the resonant frequency?