Reliability performance of 25 Gbit s⁻¹ 850 nm vertical-cavity surface-emitting lasers

Abstract

Multimode 850 nm vertical cavity surface-emitting lasers (VCSELs) suitable for high bit rate operation are studied. VCSELs with oxide aperture diameters of 5-7 μm show a high −3 dB modulation bandwidth (∼20 GHz) and D-factor (∼ 8 GHz mA −1/2 ). To allow low capacitance a multiple layer oxide-confined aperture design was applied. Eye diagrams are clearly open up to 35 Gbit s −1 at the temperature of 25 • C. Using 35 μm diameter PIN photodiodes and 6 μm oxide aperture diameter VCSELs error-free 25 Gbit s −1 (defined as a bit error ration of 1 × 10 −12 ) optical fiber communication links were tested over 100 m of standard OM3 multimode optical fibers at 25 • C and 85 • C. The received optical power for error-free operation was below −4 dBm at both temperatures. A VCSEL reliability study at 95 • C was performed at the high current densities (∼18 kA cm −2 ) needed for error-free 25 Gbit s −1 operation at elevated temperatures. After 6000 h a slight increase (less than 5%) of the output optical power at a constant current was observed and most likely due to an ohmic contact burn in effect within the first 2000 h of the study. The results clearly indicate that 25 Gbit s −1 850 nm oxide-confined VCSELs with a complex AlGaO multilayer aperture design and with step-graded Al-compositions have the potential for reliable operation.

Design and Evaluation of a Handheld Quantum Key Distribution Sender module

“…The first component under evaluation is a commercial multi-mode VCSEL array from VI Systems emitting light around 858 nm and engineered for 28 Gb.s −1 operation [23]. Single-mode VCSELs would be preferable but arrays are unfortunately not on the market yet.…”

Anomalous lasing of high-speed 850 nm InGaAlAs oxide-confined vertical-cavity surface-emitting lasers with a large negative gain-to-cavity wavelength detuning

“…The devices with oxide aperture square sides of 6 lm or less have smooth light-current (L-I) curves similar to the conventional oxideconfined 850 nm VCSELs with a more typical $10 nm negative gain-to-cavity detuning. 4 At the same time, the L-I curves for our 850 nm VCSELs with oxide aperture square sides of 7 and 8 lm shown in Figure 2(a) have an anomalous behavior (kinks or abrupt nonlinearities in the light-current curve) at intermediate forward currents. For example, the dependence of the L-I slope efficiency on current for a 7 lm  7 lm square aperture VCSEL has three distinct regions (see the inset in Figure 2(a)): (1) a rapid increase and saturation at 0.23 W/A due to the appearance of lasing with a threshold current of 1.5 mA (current region I); (2) a quick switching to lasing with an L-I slope of 0.61 W/A (current region II); and (3) a monotonic decrease in the L-I slope due to overheating (current region III).…”

“…V C 2014 AIP Publishing LLC 105, 061104-1 structure of the strained quantum-well InAlGaAs active region, DBR modulation doping to obtain a low series resistance and low internal optical losses, and the use of multiple oxide layers to achieve a small VCSEL mesa capacitance. 4 Post-growth processing included contact photolithography, dry etching, selective wet oxidation of the high AlAs molefraction AlGaAs layers, vacuum e-beam p-and n-contact metal deposition, planarization using a thick dry-etch BCB layer, and Ti/Pt/Au contact pad metallization. Photomasks were designed such that sets of adjacent VCSELs with square oxide aperture edge dimensions of from 0 lm to 8 lm were formed in one fabrication process.…”

Высокоскоростные Полупроводниковые Вертикально-Излучающие Лазеры Для Оптических Систем Передачи Данных (Обзор)

“…Это позволяет достичь более высоких резонансных частот (рис. 4, a), однако резкий рост электрических и тепловых сопротивлений при уменьшении латеральных размеров токовой апертуры приводит к сильному саморазогреву лазеров, что в сочетании с высокими значе-ниями коэффициента затухания релаксационных колебаний лимитирует диапазон рабочих токов, при которых достигается высокая частота эффективной модуляции, и ограничивает скорость передачи данных для одномодовых лазеров на уровне 25 Gbit/s [73,74]. В результате оптимальный размер токовой апертуры, обеспечивающий максимальное быстродействие ВИЛ, типично лежит в диапазоне 4−8 µm (рис.…”