List of Footnotes

1		In many implementations of numerical matrix solvers the input vector is also called the right-hand side vector.
2		Note that in other publications the tuning or equivalent microscopic displacements are sometimes defined via an optical path-length difference. In that case, a tuning of $2π$ is used to refer to the change of the optical path length of one wavelength, which, for example, if the reflection at a mirror is described, corresponds to a change of the mirror’s position of $λ0∕2$ .
3		The signal sidebands are sometimes also called audio sidebands because of their frequency range.
4		The term effective refers to that amount of incident light, which is converted into photo-electrons that are then usefully extracted from the junction (i.e., do not recombine within the device). This fraction is usually referred to as quantum efficiency $η$ of the photodiode.
5		Please note that in the presence of losses the coupling is defined with respect to the transmission and losses. In particular, the impedance-matched case is defined as $T1 = T2 ⋅Loss$ , so that the input power transmission exactly matches the light power lost in one round-trip.
6		Also known as the far-field angle or the divergence of the beam.
7		Please note that this formula from [50 ] is very compact. Since the parameter $q$ is a complex number, the expression contains at least two complex square roots. The complex square root requires a different algebra than the standard square root for real numbers. Especially the third and fourth factors can not be simplified in any obvious way: $( )1∕2( ∗ )n∕2 ( n+1∗n )1∕2 qq(0z) q0qq∗0q((zz)) ⁄= qq0n+1q(z)(q∗0zn)$ !
8		[50 ] states that the indices must obey the following relations: $0 ≤ \|l\| ≤ p$ . However, that is not the case.