Tuning of a DRO
In a DRO we resonate both signal and idler
- integer number of half wavelengths of signal must fit into cavity
- integer number of half wavelengths of idler must fit into cavity
- signal and idler frequency must sum to the pump frequency
If we take Ls and Li to be the effective lengths of the laser cavity for the signal and idler respectively we find that the conditions on ws and wi are
where ms and mi are the number of half wavelengths for the signal and idler respectively
We have three equations and two unknowns
- this is an overconstrained problem
- it gives rise to very erratic tuning