Uniform performance of high-efficiency room-temperature GaInAsSb/GaSb photodiodes for 1.75 < lambda < 2.2 mum.
A group of 126 experimental, packaged, backilluminated, 1.75-2.2-microm wavelength, GaInAsSb mesa (~85-microm diameter) photodetectors have been assembled and evaluated. Average room-temperature properties were peak quantum efficiency, 86%; zero-bias capacitance, 3.9 pF; dark current at -0.5-V bias, 7.4 microA.
Room-temperature GaInAsSb/AlGaAsSb DH injection lasers at 2.2 μm
Double-heterostructure lasers based on the GaInAsSb/AlGaAsSb system have been prepared by liquid-phase epitaxy and operated in the 2.2 μm-wavelength region. Room-temperature, pulsed threshold current densities of 6 kA/cm2 and characteristic temperatures of T 0= 85 K have been obtained.
Effects of reservoir volume on performance of pulse tube cooler.
A pulse tube cooler has the advantages of long-life and low-vibration over conventional cryocoolers such as G-M and Stirling coolers because of the absence of moving parts at low temperature. On the other hand, the combination of a reservoir and orifice is indispensable to optimize the performance of pulse tube coolers. In order to make the pulse tube cooler compact for practical applications, the volume of reservoir should be minimized. This paper analyzes the effects of the reservoir volume on the thermodynamic performance of various components in a simple orifice and a double-inlet pulse tube cooler by combining a linearized model with a thermodynamic analysis. Expressions of entropy production for those components are presented. The results show that the reservoir volume has a significant influence on the entropy production in the various components when the reservoir to pulse tube volume ratio is smaller than about 5. The ratio is important to determine the minimum reservoir volume for a pulse tube cooler. Optimum settings for a double-inlet pulse tube cooler are also discussed.