  To recognize gravitational wave lensing events and being able to
differentiate between similar lens models will be of crucial importance once
one will be observing several lensing events of gravitational waves per year.
In this work, we study the lensing of gravitational waves in the context of
LISA sources and wave-optics regime. While different papers before ours studied
microlensing effects enhanced by simultaneous strong lensing, we focus on
frequency (time) dependent phase effects produced by one lens that will be
visible with only one lensed image. We will show how, in the interference
regime (i.e. when interference patterns are present in the lensed image), we
are able to i) distinguish a lensed waveform from an unlensed one, and ii)
differentiate between different lens models. In pure wave-optics, on the other
hand, the feasibility of the study depends on the SNR of the signal and/or the
magnitude of the lensing effect. To achieve these goals we study the phase of
the amplification factor of the different lens models and its effect on the
unlensed waveform, and we exploit the signal-to-noise calculation for a
qualitative analysis.
