Peak gain wavelength tuning via the gain-lever effect is demonstrated in segmented contact InP quantum dot Fabry–Perot lasers. A tuning range of 6.5 ± 0.1 nm was recorded in the lasing spectra of a ...1.9 mm long broad area device operating at 22°C. The authors clarify the nature of the tuning mechanism and identify the critical material and device parameters that determine the limits of the wavelength tuning range.
We explore the origins of the threshold current temperature dependence in InP quantum-dot (QD) lasers. While the internal optical mode loss does not change with temperature, the peak gain required to ...overcome the losses becomes more difficult to achieve at elevated temperature due to the thermal spreading of carriers among the available states. In 2-mm-long lasers with uncoated facets, this effect is responsible for 66% of the difference in threshold current density between 300 and 360 K. Spontaneous recombination current only makes up at most 10% of the total recombination current density over this temperature range, but the temperature dependence of the spontaneous recombination in the QD and quantum-well capping layers can be used, assuming only a simple proportional nonradiative recombination process, to explain the temperature dependence of the threshold current density.
Al In P SAM-APD as a Blue-Green Detector Jeng Shiuh Cheong; Ong, J. Siok Lan; Jo Shien Ng ...
IEEE journal of selected topics in quantum electronics,
2014-Nov.-Dec., 2014-11-00, 20141101, Letnik:
20, Številka:
6
Journal Article
Recenzirano
We demonstrate an Al 0.52 In 0.48 P homo-junction Separate Absorption Multiplication Avalanche Photodiode as a detector with narrow spectral response in the blue-green part of the optical spectrum. ...Due to its wide band-gap, this device has a dark current density of <; 8 nA cm -2 at 99.9% of the breakdown voltage at room temperature. This device has a peak responsivity at 483 nm of 0.15 A/W when punched-through and is capable of an avalanche gain higher than 100.
We review the recent development of high-performance short-wavelength (λ ~ 3.05-3.8 μm) strain-compensated InGaAs/AlAs(Sb)/InP quantum cascade lasers (QCLs). The lasers are demonstrated in which ...wavelengths as low as 3.05 μm are obtained at temperatures up to 295 K. We also verify that strain-compensated In 0.7 Ga 0.3 As/AlAs(Sb) QCLs with AlAs barriers in the active region operate with much better performance compared with the lasers having identical design but with AlAsSb barriers throughout the whole core region. λ ~ 3.3-3.7 μm laser emission is observed at temperatures up to at least 400 K and up to 20 W of output optical power at 285 K for the QCLs with various core region designs. Room temperature distributed feedback InGaAs/AlAs(Sb) QCLs with buried third-order gratings have been also developed, displaying single-mode operation in the wavelength range of 3.358-3.380 μm for temperatures between 270 and 360 K.
We demonstrate the use of a novel InGaP quantum-dot (QD) saturable absorber (SA) to induce passively mode-locked (ML) operation of a Ti : sapphire laser. Pulses as short as 518 fs are obtained at 752 ...nm with an average output power of up to 190 mW for 2.3 W of absorbed pump power at 532 nm. The absorption recovery of the SA is characterized by two decay coefficients: a fast and a slow component having time constants of 0.4 and 300 ps, respectively. The saturation fluence of the InGaP QDs was measured to be 28 ¿J/cm 2 , the initial low-signal absorption was 1.5%, where 1.15% was nonsaturable loss.
We report measurements which give direct insight into the origins of the transparency current for λ ~5 µm In0.6Ga0.4As/In0.42Al0.58As quantum cascade lasers in the temperature range of 80-280 K. The ...transparency current values have been found from broadband transmission measurements through the laser waveguides under sub-threshold operating conditions. Two active region designs were compared. The active region of the first laser is based on double-LO-phonon relaxation approach, while the second device has only one lower level, without specially designed resonant LO-phonon assisted depopulation. It is shown that transparency current contributes more than 70% to the magnitude of threshold current at high temperatures for both designs.
We report a proof-of-principle of surface detection with air-guided quantum cascade lasers. Laser ridges were designed to exhibit an evanescent electromagnetic field on their top surface that can ...interact with material or liquids deposited on the device. We employ photoresist and common solvents to provide a demonstration of the sensor setup. We observed spectral as well as threshold currents changes as a function of the deposited material absorption curve. A simple model, supplemented by 2D numerical finite element method simulations, allows one to explain and correctly predict the experimental results.
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