Return the instantaneous coherent fluxes and photometric fluxes for a
    multiway single-mode fibre combiner

def SingleModeCombine(pupils,modeDiameter=None):
    """
    Return the instantaneous coherent fluxes and photometric fluxes for a
    multiway single-mode fibre combiner
    """
    if modeDiameter is None:
        modeDiameter=0.9*pupils.shape[-1]
    amplitudes=FibreCouple(pupils,modeDiameter)
    cc=np.conj(amplitudes)
    fluxes=(amplitudes*cc).real
    coherentFluxes=[amplitudes[i]*cc[j]
                    for i in range(1,len(amplitudes))
                    for j in range(i)]
    return fluxes,coherentFluxes