1. A method for autonomously determining a modulation format of an optical signal, the method comprising: responsive to receiving the optical signal from a transmitter, converting the optical signal into an input signal; mapping the input signal to Stokes space to generate a representation of the input signal in three-dimensional space, the representation taken to follow a Gaussian mixture model; determining the dimension of the representation of the input signal in three-dimensional space; based on the dimension of the representation of the input signal in three-dimensional space having two dimensions in Stokes space: defining at least one cost function for identifying the modulation format of the input signal in from among OOK, BPSK, QPSK, M-PAM, and M-PSK, the cost function based at least in part on concentration parameters of mixing probabilities of the Gaussian mixture; and evaluating the at least one cost function to identify the modulation format of the input signal from among OOK, BPSK, QPSK, M-PAM, and M-PSK; based on the dimension of the representation of the input signal in three-dimensional space having three dimensions in Stokes space, identifying the modulation format of the input signal to be M-QAM for M≠{2;4}.