Increasingly, 3D sensing is becoming a ubiquitous technology – especially in consumer applications. Underlying this trajectory are diode lasers that emit light to measure, examine, and assess the world. There are two diode laser types: vertical-cavity surface-emitting laser (VCSEL), and edge emitters. Each laser with characteristics ideal for specific tasks. Reliability, consistency, and the ability to scale are critical for the demanding consumer markets. Even in the most severe environments – undersea -- diode lasers keep Internet traffic flowing. This presentation will examine diode laser history, recent gaming uses, and current-day gesture and facial recognition for smartphones. Also, promise for autonomous driving.
Ground-based mid-infrared (mid-IR) observations appear to be widely perceived as esoteric and demanding, and
very sensitive to observing conditions. Although the principles of observing in the background-limited regime
are well-known, it is difficult for the non-specialist to find specific information on exactly how mid-IR data can
be affected by environmental conditions. Understanding these effects is important for the efficiency of mid-IR
queue observing, the ability of classical observers to adapt their programs to the prevailing conditions, and the
standard of data being delivered. Through operating mid-IR instruments in the queue at Gemini we have amassed
a considerable database of standard star observations taken under a wide range of atmospheric conditions and in
a variety of instrumental configurations. These data can be used to illustrate the effect of factors such as water
vapour column, airmass, cloud cover, etc. on observed quantities like raw sky background, residual background,
atmospheric transmission and image FWHM. Here we present some preliminary results from this study, which we
hope to be of use to observatory users and staff as a guide to which environmental conditions are truly important
to mid- IR imaging observations, and which can safely be neglected.
Results for a new compact 488 nm solid-state laser for biomedical applications are presented. The architecture is based
on a multi-longitudinal mode external cavity semiconductor laser with frequency doubling in a ridge waveguide fabricated in periodically poled MgO:LiNbO<sub>3</sub>. The diode and the waveguide packaging have been leveraged from telecom packaging technologies. This design enables built-in control electronics, low power consumption (≤ 2.5 W) and a footprint as small as 12.5 x 7 cm. Due to its fiber-based architecture, the laser has excellent beam quality, M<sup>2</sup> <1.1. The laser is designed to enable two light delivery options: free-space and true fiber delivered output. Multi-longitudinal
mode operation and external doubling provide several advantages like low noise, internal modulation over a broad frequency range and variable output power. Current designs provide an output power of 20 mW, but laser has potential for higher power output.
Developers building high-power fiber lasers and diode pumped solid state lasers can receive significant benefits in thermal management and reliability by using single emitter multi-mode diodes in distributed pump architectures. This proposed distributed architecture relies on independent single emitter pump lasers and a modest level of pump redundancy. Driving the remaining diodes slightly harder componensates individual diode failures. A model of the ensemble lifetime based on module failure rates and power-scaling factors demonstrates that the distributed pump architecture requires random failure rates corresponding to better than 200,000h mean time between failure (MTBF), which meets typical industrial requirements. A high power, pigtailed, multi-mode pump module suitable for commercial applications is created through this model. Critical elements are based on telecom architectures, including the optical train and the fiber alignment. The module has a low thermal resistance of 4°C/W from the chip-on-sub-mount to the external heat sink, coupling efficiency of over 80% into 0.2 NA, and demonstrated reliable output power of over 5W cw with peak wavelengths near 915 nm. Individual pump modules are predicted to produce 5W cw output power with an MTBF of more than 400,000h. The relationship between anticipated MTBF requirements, test duration and test population is shown.
Multi-mode pumps based on single emitter diodes deployed in distributed pump architectures offer significant advantages in thermal management and reliability for pumping high-power fiber lasers and amplifiers. In a distributed architecture, while individual diode failures do not directly generate failures of other diodes in the distributed ensemble, failures do cause the rest of the sources to drive to higher power levels to compensate for the loss of power. A model of the ensemble lifetime based on module failure rates and power-scaling factors demonstrates that the distributed pump architecture requires random failure rates corresponding to better than 200,000 h mean time between failure (MTBF) to meet typical application requirements. A high power multi-mode pump module suitable for commercial aplications is shown. Critical elements are based on telecom architectures, including the optical train and the fiber alignment. The module has a low thermal resistance of 4 C/W from the laser diode junction to the external heat sink, couplng efficiency of over 80% into 0.2 NA, and demonstrated reliable output power of over 5W CW with peak wavelengths near 915 nm. Telecom qualified modules have random failure rates corresponding to better than 1,000,000 h MTBF. Stability of the critical fiber alignment joint for single mode packages has been demonstrated at elevated temperatures (e.g. 85 C) for thousands of hours. The reliability of the commercial multi-mode package can be estimated by similarity to the telecom package, and is verified by testing of conditions considered to be at risk based on the differences between the known telecom, and the new commercial package, designs. Test results are shown for temperature cycling, CW operation, and damp heat. The relationships between anticipated MTBF requirements, test duration and test population are shown.