IR sensors transform LiDAR and rangefinder with optical fibre test performance

30-01-2024 | Phlux Technology | Semiconductors

Phlux Technology announced its first products, the Aura family of 1550nm devices based on the company's Noiseless InGaAs APD technology. The sensors are 12X more sensitive than conventional best-in-class InGaAs APDs. Consequently, the operating range of LiDAR, laser rangefinders, and optical fibre test equipment can be extended by up to 50% with the company's sensors, which are drop-in replacements for existing surface mount or TO-packaged components.

In new designs, the sensors facilitate 12X greater LiDAR image resolution for a given laser power, up to 30% reduction in system size and weight, and up to 40% lower system costs. The size and cost reductions come from employing lower-power lasers and smaller optical apertures without impacting system performance. Also, thermal management is simplified because Aura APDs operate at up to +85C without performance degradation, which is a particularly higher temperature than conventional parts.

Phlux CEO, Ben White, said, "Our Noiseless APD technology is a step-function leap in performance and provides tangible benefits for any company involved with 1550nm lasers. Automotive LiDAR is an exciting application where the move from 905nm to 1550nm lasers is accelerating, not least because the latter is 'eye-safe'. But there are also huge opportunities for our products in telecommunications, laser rangefinders, imaging, spectroscopy, gas sensing and optical fibre test equipment, particularly optical time domain reflectometers."

The company created its Noiseless InGaAs APD technology by adding an antimony alloy to the compound semiconductor manufacturing process. The resulting sensors can be operated with APD gains up to 120, allowing even the smallest signals above the noise floor of a connected TIA to be amplified. A further benefit of the APDs is their rapid overload recovery, which means weaker secondary pulses that closely follow a large pulse can be detected.

The Aura APD 200 (200µm optical aperture) and Aura APD 80 (80µm optical aperture) sensors are obtainable as bare die or in industry-standard SMD, chip on sub-mount, and TO-46 packages designed to meet MIL-STD 883.

Typical parameters for the devices are responsivity of 0.98A/W at 1550nm, spectral range of 950nm to 1700nm, and excess noise factor of 1.86 at an avalanche gain of 40, or 1.08 at an avalanche gain of 10.

At a gain of 10, the noise equivalent power for the APD 200 diode is 17fW/Hz0.5, its capacitance 2.4pF and its cut-off frequency 0.7GHz. The equivalent figures for the APD 80 are 11.1fW/Hz0.5, 0.6pF, and 1.8GHz.

These devices have a typical operating voltage of -55V to -65V and a breakdown voltage of -65V, and their operating temperature range is -40C to +85C.

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By Seb Springall