Temperature-stable Performance Research Articles

Silicon-Integrated Hybrid-Cavity 850-nm VCSELs by Adhesive Bonding: Impact of Bonding Interface Thickness on Laser Performance

The impact of bonding interface thickness on the performance of 850-nm silicon-integrated hybrid-cavity vertical-cavity surface-emitting lasers (HC-VCSELs) is investigated. The HC-VCSEL is constructed by attaching a III–V “half-VCSEL” to a dielectric distributed Bragg reflector on a Si substrate using ultrathin divinylsiloxane-bis-benzocyclobutene (DVS-BCB) adhesive bonding. The thickness of the bonding interface, defined by the DVS-BCB layer together with a thin SiO2 layer on the “half-VCSEL,” can be used to tailor the performance, for e.g., maximum output power or modulation speed at a certain temperature, or temperature-stable performance. Here, we demonstrate an optical output power of 2.3 and 0.9 mW, a modulation bandwidth of 10.0 and 6.4 GHz, and error-free data transmission up to 25 and 10 Gb/s at an ambient temperature of 25 and 85 °C, respectively. The thermal impedance is found to be unaffected by the bonding interface thickness.

A 0.6V 75nW All-CMOS Temperature Sensor With 1.67m°C/mV Supply Sensitivity

This paper presents the design of a fully-integrated ultra-low-power temperature sensor applicable for use in wearable, environmental monitoring, and Internet-of-Things applications. Temperature is transduced in the proposed design by charging a pair of capacitors with proportional to or complementary to (proportional to absolute temperature or complementary to absolute temperature) current sources, and converting temperature-varying charging times to digital via a time-to-digital converter clocked by an on-chip temperature- and supply-stabilized 30-kHz relaxation oscillator. A low-voltage pseudo-differential dual-loop current reference generator is employed alongside inverter-based comparators to impart supply- and temperature-stable performance at low power. Fabricated in $0.18\mu \text{m}$ CMOS, the design operates at 0.6 V and consumes 75 nW at room temperature. Across a temperature range of 0 °C–100 °C, the sensor achieves a best-case (worst-case) temperature accuracy of +0.47 °C/−0.22 °C (+0.62 °C/−1.33 °C) and a resolution of 0.093 °C (0.1 °C). Across a supply range of 0.55–−0.85 V, the sensor achieves an inaccuracy of +0.19 °C/−0.28 °C.

Pavement Performance of Hot In-Place Recycling for Waste Asphalt Mixtures

With the early asphalt pavements have been into the stage of medium maintenance or overhaul, recycling is a very important way for waste asphalt mixtures. A sample was taken in the expressway from Huhhot to Baotou, and the waste mixtures were extracted from field and sieved; so that the new aggregates can be determined and mix design was carried. With the aid of the penetration, the softening point and the viscosity in 135°C test, the quantity of the regenerant and the asphalt content were ascertained. Through the high temperature stable performance, the anti-low temperature performance, the water stability and the Hamburg wheel-tracking test, the appropriate gradation and the optimum asphalt content were determined. The test results showed that the pavement performance of the waste asphalt mixture was enhanced obviously with hot in-place recycling, and it has achieved technical parameters for old asphalt mixture.