What type of photodetector is used in lidar

LIDAR Overview

LIDAR emits laser light into space, the light travels along a straight line and is reflected when it encounters an obstacle, and the detection system detects the reflected backlight and obtains information about the obstacle in the air through computerized calculations, which is a kind of optoelectronic system device.

Characteristics of LIDAR applications

• LIDAR's return power is often very low and requires amplification circuits.
• LIDAR laser pulse signals are often more than the M level
• Commonly, LIDAR adopts the wavelength of 1550nm, 1064nm, 905nm.
• LIDAR according to the different technical solutions, there are TOF principle, there are FMCW principle

What type of photodetector is used for LIDAR?

The type of photodetector to be used depends on the detection scheme of the LIDAR, an APD type of photodetector is selected if the LIDAR is based on the TOF principle, and a BPD balanced photodetector is selected if the LIDAR is based on the FMCW principle.

TOF principle, 1064nm light source, selection of 1064nm enhanced photodetectors

https://www.ybphotonics.com/product/35

1064nm APD avalanche detector for lidar, atmospheric aerosol detection，The detector is based on a silicon-based avalanche photodiode with 1064 nm enhanced response and high gain response for atmospheric aerosol radar。

TOF principle, 1550nm light source, choose photodetector of APD430C series

https://www.ybphotonics.com/product/10

APD430 free-space InGaAs APD photodetector Bandwidth 10M to 400M, suitable for detecting nW optical power from 400-1700nm with noise down to 20mV

TOF principle, 905nm light source, choose photodetector of APD430A series

https://www.ybphotonics.com/product/10

APD430 series of free-space APD photodetector modules, wavelength range covering the visible and near-infrared region, can be used to replace Thorlabs the same model parameters; suitable for free-space optical applications detection, such as LIDAR.

FMCW principle, 1550nm light source, choice of balanced photodetector BPD570 or BPD465

https://www.ybphotonics.com/products?Category=Photodetector%20Module&type=Balanced%20Photodetector

The Avalanche Photodiode Balanced Detector is a balanced receiver that eliminates common mode noise by subtracting the two input signals. The balanced detector uses two matched avalanche photodiodes (APDs) and an ultra-low noise, ultra-low distortion, high-speed transimpedance amplifier ideal for low optical input power applications. Each APD is coupled through length-matched SMF-28e+ fiber optics at the FC/APC end to avoid optical range differences between the input and the active region of the photodiode. Unique to the BPD570, compared to other balanced detectors using silicon or Indium Gallium Arsenide (IGA) PIN photodiodes, is the extremely low NEP and optical gain control.

Summarize

Commonly, LIDAR uses light wavelengths such as 1550nm, 1064nm, 905nm, etc. Since the return power is very weak, the detector type used is an APD photodetector. If the radar is FMCW principle, then the BPD type photodetector is used.