Design and analysis of high-temperature operating 795 nm VCSELs for chip-scale atomic clocks

Abstract

We propose a new structure design and analysis of high-temperature (>350 K) operating 795 nm vertical-cavity surface-emitting lasers (VCSELs) for 87 Rb based chip-scale atomic clocks (CSACs). Compositions and thicknesses of the InAlGaAs/AlGaAs multiple quantum wells (MQWs) are optimized for high optical gain at elevated temperatures. The temperature sensitivity of the threshold current is estimated by calculating the temperature dependence of the cavity-mode gain. A self-consistent VCSEL model based on quasi-3D finite element analysis is employed to investigate the temperature distribution and output of the proposed structure. An output of 1 mW with a 3 dB bandwidth of 6 GHz is obtained from a 3 µm aperture VCSEL under 2.4 mA current at temperature higher than 340 K. These findings indicate that high-gain QWs and gain-offset consideration are especially crucial to make high-performance VCSELs at elevated temperatures.

Chip-scale atomic devices

“…VCSELs at 895 nm have been designed to address this problem by intentionally detuning the optical cavity from the gain peak at room temperature such that the coincidence of the two is better at elevated temperature. 91,92 Extended lifetime testing of commercial 795 nm lasers at elevated temperature and current has been carried out in the context of magnetometers for space missions. 93 This testing suggested that VCSELs from some suppliers can support mission durations as long as 17 years without failure.…”

Directly-coupled well-wire hybrid quantum confinement lasers with the enhanced high temperature performance

“…The quantum-confined semiconductor lasers, e.g. quantumwell and quantum-dot lasers have been widely applied for various fields, including optical fiber communication, optical interconnection, atomic clock and scientific research, etc [1][2][3], where the InGaAs-based laser diodes show the * Author to whom any correspondence should be addressed.…”

Design and performance of high temperature operating resonant-cavity photodiodes based on 795 nm-VCSEL structure

“…For the high temperature operation of RCPD/VCSEL, the photoluminescence (PL) emission peak and cavity mode (CM) are coincident near the desired operating temperature (360 K) . The wavelength of the QW emission peak is shorter than that of CM at room temperature .…”