Photon Photon Resonance Shown in DFB

PICWave is an advanced dynamic circuit and laser diode simulator. This example demonstrates PICWave’s ability to simulate photon-photon resonance through the 3D simulation of a DFB laser responding to an electrical impulse.

The characteristic result of photon-photon resonance is to see multiple peaks in the laser’s response to an impulse. This is shown in the results of PICWaves simulation of a DFB laser with an additional cavity section.

Without photon-photon resonance we would expect to see a single resonance peak.

Why?

A large instantaneous current injection acts to sharply increase the carrier density, increasing the optical gain, and consequently the photon density. The larger photon density then depletes the carriers through stimulated emission, creating a cyclic response.

If the laser is operated under direct modulation at the ‘relaxation oscillation frequency’, the modulation is synchronised with these natural oscillations described above. When at this resonance, each cycle of the injected current adds energy to the previous one, reinforcing the oscillations and producing the resonance peak. 

At higher modulation frequencies, the carrier and photon populations cannot respond quickly enough, so the modulation response rolls off.

This can be seen in a simulation of a similar DFB where the additional waveguide cavity section is removed.