An InAs/InGaAs quantum dot laser with a heterostructure epitaxially grown on a silicon substrate was used to fabricate injection microdisk lasers of different diameters (15-31 µm). A post-growth ...process includes photolithography and deep dry etching. No surface protection/passivation is applied. The microlasers are capable of operating heatsink-free in a continuous-wave regime at room and elevated temperatures. A record-low threshold current density of 0.36 kA/cm
was achieved in 31 µm diameter microdisks operating uncooled. In microlasers with a diameter of 15 µm, the minimum threshold current density was found to be 0.68 kA/cm
. Thermal resistance of microdisk lasers monolithically grown on silicon agrees well with that of microdisks on GaAs substrates. The ageing test performed for microdisk lasers on silicon during 1000 h at a constant current revealed that the output power dropped by only ~9%. A preliminary estimate of the lifetime for quantum-dot (QD) microlasers on silicon (defined by a double drop of the power) is 83,000 h. Quantum dot microdisk lasers made of a heterostructure grown on GaAs were transferred onto a silicon wafer using indium bonding. Microlasers have a joint electrical contact over a residual
+ GaAs substrate, whereas their individual addressing is achieved by placing them down on a
-contact to separate contact pads. These microdisks hybridly integrated to silicon laser at room temperature in a continuous-wave mode. No effect of non-native substrate on device characteristics was found.
We report on the transverse single-mode emission from InGaAs/GaAs quantum well edge-emitting lasers with broadened waveguide. The lasers are based on coupled large optical cavity (CLOC) structures ...where high-order vertical modes of the broad active waveguide are suppressed due to their resonant tunneling into a coupled single-mode passive waveguide. The CLOC lasers have shown stable Gaussian-shaped vertical far-field profiles with a reduced divergence of ∼22° FWHM (full width at half-maximum) in CW (continuous-wave) operation.
We report on the fabrication and studies of Ø100 μm half-disk lasers with an active region based on InGaAs/GaAs quantum dots providing very high modal gain. Such resonators support whispering gallery ...modes propagating at the cavity periphery. The microlasers show directional light outcoupling: continuous-wave output power emitted from the flat side reaches 17 mW, which is about 7 times greater than the power emitted from the back semicircular side. Single-mode lasing in a wide range of the injection currents is observed. P-side down bonding of the devices onto Si-board allowed increasing the maximum optical power to more than 30 mW and the lasing was observed up to 93°C. The 3 dB modulation bandwidth of 4.6 GHz was measured likely being limited by RC-parasites.
We study the applicability of InGaAs/GaAs quantum well-dots (QWDs) for active regions of broadband superluminescent diodes (SLDs) emitting in the 950–1150 nm spectral range; 2 mm long SLDs with a ...bent section and an active region based on seven chirped QWD layers show emission spectra centered at 1030 nm with a full-width at half-maximum of 80 nm and an output power of 2 mW. In a 250 µm long SLD with a tilted stripe that has an increased output loss, the width of the emission spectra is 113 nm at 20 °C and 120 nm at 60 °C.
Abstract
An original design of ring semiconductor lasers based on InAs/InGaAs/GaAs quantum dots, promising for clock pulse generation, optical sensing, biological and medical applications, and ...microwave photonics, has been proposed and tested. Lasing was obtained at room temperature with a nominal threshold current density as low as 150 A cm
−2
. The output power in continuous wave mode was 45 mW.
Abstract
Half-disk lasers fabricated by cleaving initial full-disk lasers have an advantage of directional light outcoupling as well as increased output power and efficiency as compared to full-disk ...lasers of the same diameter. The continuous wave output power of a 200
µ
m diameter half-disk laser exceeds 70 mW. Quasi single-mode lasing with a high side-mode suppression ratio more than 20 dB is demonstrated for half-disk lasers of various diameters. A maximum 3 dB small signal modulation frequency of 4.9 GHz was measured for a 100
µ
m in diameter half-disk laser.
Abstract
Characteristics of a compact III–V optocoupler heterogeneously integrated on a silicon substrate and formed by a 31
µ
m in diameter microdisk (MD) laser with a closely-spaced 50
µ
m × 200
µ
...m waveguide photodetector are presented. Both optoelectronic devices were fabricated from the epitaxial heterostroctructures with InGaAs/GaAs quantum well-dot layers. The measured dark current density of the photodetector was as low as 2.1
µ
A cm
−2
. The maximum link efficiency determined as the ratio of the photodiode photocurrent increment to the increment of the microlaser bias current was 1%–1.4%. The developed heterogeneous integration of III–V devices to silicon boards by Au-Au thermocompression bonding is useful for avoiding the difficulties associated with III–V epitaxial growth on Si and facilitates integration of several devices with different active layers and waveguides. The application of MD lasers with their lateral light output is promising for simplifying requirements for optical loss at III–V/Si interface.
Microdisk lasers demonstrate high performance and low threshold characteristics due to supporting of whispering gallery modes with a high quality factor. One of the challenging problems impeding some ...practical applications of whispering gallery mode lasers is that they have isotropic emission predominantly lying in the plane of the cavity. In this work, we present a novel method that provides both enhancement of the laser emission and modifies its directivity, making the vertical direction favorable. Electromagnetic energy outcouples from the cavity through the platinum–carbon plasmonic wire nanoantenna grown by electron-beam assisted deposition right up the side wall of the cavity. Evanescent field of whispering gallery mode excites surface plasmon polariton which propagates along the nanoantenna and scatters at its tip. We demonstrate 20× enhancement of the dominant mode intensity with 24 dB of side mode suppression increment without essential worsening of the Q-factor which remains over 3 × 104. The proposed approach of the efficient control over the spectrum, directivity, and emission efficiency from microdisk lasers could be very promising for many practical applications from telecommunication technologies to biosensing.
A drastic reduction in the residual voltage (from ~ 100 V to a few volts) and a significant (factor of ~ 2) increase in the dU / dt switching rate is demonstrated experimentally in the superfast ( ~ ...200 ps) avalanche switching of a GaAs bipolar junction transistor with increased emitter area. This result is not a trivial one as only a small number of conductive channels of a few micrometers in diameter participate in the transient independently of the emitter size, while the remaining (passive) part of the structure supplies the switching channels with the currents circulating inside the chip, which makes the impact ionization in the filaments even more powerful. Excellent agreement was found between the experiment and a ¿two-transistor¿ model specially developed here, with one transistor simulating the switching channels and the other the nonswitched part of the structure. Much higher switching stability and reproducibility and much lower power dissipation were observed in the structure with increased emitter area.
Room Temperature Lasing in 1-μm Microdisk Quantum Dot Lasers Kryzhanovskaya, Natalia V.; Zhukov, Alexey E.; Maximov, Mikhail V. ...
IEEE journal of selected topics in quantum electronics,
2015-Nov.-Dec., 2015-11-00, Letnik:
21, Številka:
6
Journal Article
Recenzirano
Lasing characteristics of InAs/InGaAs quantum dot microdisks with diameter varied from 1 to 6 μm were studied under optical pumping. The disks were fabricated with standard photolithography and ...two-step wet etching. We demonstrate room temperature lasing in the 1.29-1.32-μm wavelength range (ground-state transition) in microlasers as small as 1 μm in diameter. The microlasers demonstrate narrow linewidths (40-60 pm), low thermal impedance (85°C/mW), and low threshold powers (50-100 μW).
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