Photonic Crystal VCSELs: Detailed Comparison of Experimental and Theoretical Spectral Characteristics

We present a detailed comparison of experimental and simulated optical spectra obtained from a 980-nm photonic-crystal (PhC) VCSEL. We demonstrate good qualitative agreement of the experimental spectra with the calculated emitted wavelengths for number of VCSEL structures with different PhC designs. We show the statistical analysis which reveals that strong confinement introduced by the photonic crystal contributes to the conformity between experiment and theory. For shallow etching of the photonic crystal holes, narrow optical aperture, and large diameter air-holes, we observe that diffraction and mode leakage through the PhC holes becomes the dominating phenomena, and then any fabrication imperfection may contribute to discrepancy between theory and experiment.