We proposed a plasmonic lens (PL) to achieve far-field focusing performance under a 532 nm wavelength. This lens is produced by perforating multiple concentric rings on the gold layer, and the radius and width of the ring can be designed flexibly. Its machining process has adopted the electron beam lithography and lift-off technology. The lenses are designed within a small range of phase delay and the small-sized slits of the PL are replaced with a larger-sized one, which has almost no impact on either the full width at half maximum (FWHM) or the focal length of the PL. With an increase of the slits width, a further enhancement of the spot intensity has been observed. Meanwhile, both the numerical relationships of simulation and experiment are consistent. This method can reduce the difficulty of PL processing, by which the PL with large-sized slits has almost the same performance as that of small-sized ones. The method is of great significance to the low-cost production of modern optoelectronic devices, and it would promote potential applications in optical interconnection devices, controllable focusing, and superresolution imaging.
To our knowledge, this is the first report of a monolithically integrated distributed feedback (DFB) semiconductor laser
array based on reconstruction-equivalent-chirp (REC) technology. A laser bar with 30 different lasers is obtained, lasing
at 30 different wavelengths under single longitudinal mode. The typical threshold is about 40mA to 60mA. The typical
slope efficiency is about 0.07 mW/mA to .13 mW/mA. Tested under the injection current of 100mA, the side mode
suppression ratios (SMSR) range from 24.9dB to 46.8 dB, with an average of 37.2dB. The proposed method is presented
in hoping to make a positive contribution to large-scale photonics integrated circuits (PIC) research for the nextgeneration
A complex-coupled DFB Laser with the sampled grating has been designed and fabricated. The +1<sup>st</sup> order reflection of
the sampled grating is utilized for laser single mode operation, which is 1.5387μm in the experiment. The typical
threshold current of the device is 30mA, and the optical output power is about 10mW at the injected current of 100mA.