Third order ring resonators are designed and their resonance frequency deviations are analyzed experimentally by processing them with E-beam lithography and ICP etching in a CMOS nano-Fabrication laboratory. We developed a reliable method to identify and reduce experimentally the degree of deviation of each ring resonance frequency before completion of the fabrication process. The identified deviations can be minimized by the way to be presented in this paper. It is expected that this method will provide a significant clue to make a high order multi-channel ring resonators.
The butt-coupled (BT) sampled grating distributed Bragg reflector laser diode (SGDBR-LD) was designed and fabricated using planar buried heterostructure (PBH), enabling a low threshold current and a stable fundamental transverse mode. The but-coupled SGDBR-LD's with target tuning ranges of 44.4nm was fabricated, and the tuning ranges were experimentally measured to be 44.4nm. The measured peak periods of the fabricated SGDBR-LD's were well matched with theoretical values and output power is close to calculated values. The side mode suppression ratio of more than 35dB was obtained in the whole tuning range. The output power variation was less than 5dB, which is 4dB smaller than that of RWG structure.
Coherent laser light was tuned by cumulative refraction of light waves in a semiconductor laser cavity, while the wavelength of electroluminescence was not tuned by any noticeable amount. This effect is explained by the fact that the laser light has perfect spatial coherence, while the electroluminescence has a spatial coherence of 0.7 µm, smaller than the width of the wavefront. The refraction angle of 2.4 deg means that more than 16 triangular electrodes are involved in the refraction. This observation of coherent tuning may lead to a new optoelectronic device, a coherent filter, which filters out only coherent light from a coherent-incoherent mixture.
As a lightwave having a Gaussian intensity profile passes through a tilted Fabry-Perot filter, the profile is distorted severely depending on the conditions of the parameters. This distortion has not been studied and reported in depth, though the propagation of a Gaussian wave itself has been discussed well in the literature. We show our results of quantitative calculation and discuss it, which we believe will help significantly design waveguides containing gratings or filters.