Creating uneven sidebands with AM + PM modulation?
If I understand correctly, you want to use each side band as an independent information-bearing signal. In other words, you want to be able to generate $$a_k e^{2\pi f_i t}$$ with the information in carried by the amplitude $a_k$. There are several ways to do this, but I don't know which are feasible using optical processing. All of the following methods are feasible if you start with discrete signals and then convert them to optical.


Single-sideband modulation. The idea is that $$s(t)\cos(2\pi f_i t) \pm j\hat{s}(t)\sin(2\pi f_i t),$$ where $\hat{s}(t)$ is the Hilbert transform of $s(t)$, is a single side band signal or, in other words, one of the two sidebands you want to create. By choosing $+$ or $-$ you select the lower or the upper sideband.
Use the IFFT to go from any given spectrum to the time domain. This is the way OFDM works.
Use quadrature modulation (QAM). With this technique, you don't get to control each sideband independently; rather, you transmit two independent bitstreams by mixing two different versions of the sidebands. I have heard that QAM is possible to implement optically.


I hope this answer points you in some fruitful direction.