The minimum noise figure of an electrical amplifier is F_e=1. E. Desurvire's traditional optical noise F_pnf of an optical amplifier has the minimum value F_pnf=2. If F_pnf is a noise figure then power, gain and F_e need to be redefined. F_pnf is in conflict with physics and F_e. The correct optical noise figure F_o,IQ, observable in coherent I&Q receivers, has the minimum F_o,IQ=1 and is compatible with F_e. In the derivation of the consistent unified noise figure F_IQ for all frequencies, from F_e and F_o,IQ, thermal noise energy is needed. Its usual simplified expression kT is now replaced by Nyquist's correct result. This holds also in a unified homodyne noise figure F_I, against which H. Haus' unified noise figure F_fas is discussed.