We investigated a novel design concept of index-guided tapered LDs with linearly effective-refractive-index variation to make a quality beam in 808 nm for intermediate power LDs between a few decades of mW to ~ W. In this concept, the tapered width at each position in the propagation direction varies linearly depending on change in effective-refractive-index not geometry. We use GaAsP/InGaP/InGaAlP quantum well LD structure of 808 nm and standard LD fabrication processes to test. To design a detail structure, we use the effective-refractive-index method and transfer matrix method. The tapered ridge LD with linear effective-refractive-index variation shows more stable in beam quality but needs more study to optimize the structure.
In this paper, next generation 780nm monolithic individually addressable 8 beam diode laser with 10mW optical
power for laser scanning unit were developed. Beam to beam spacing is 30μm and air bridge interconnection process
was developed for individual operations. Measured average values of threshold current(Ith), operating current(Iop),
operating voltage(Vop), slope efficiency(SE), horizontal beam divergence(FFH), vertical beam divergence(FFV), and
peak wavelength(λ) from 5 specimens are 14.91mA, 28.79mA, 1.91V, 0.72mW/mA, 8.28°, 31.89°, and 785.67nm
respectively. Major electro-optic parameters from 8 emitters are within 3% variation for each device. Also we measured
power droop that had a strong influence on printing image at 600Hz with duty 10% and 90% and we can obtained droop
rate within 2% in each channel at room temperature and 10mW power. From 500Hr reliability life test result at 70°C,
we obtained Iop variation within 1% in each channel with 10mw power.
From the experimental measurement results, we can assure that the developed 8 beam diode laser is suitable optical
source for high speed laser scanning unit in multi-function printing system and laser beam printers.