Fig. 1. Schematic diagram of the multi-channel PR coding single-photon ranging system. Achromatic collimator: output beam size is 12 mm in diameter, and full angle beam divergence is 0.02° (Thorlabs RC12APC-P01). Perforated mirror: D = 50 mm, and the diameter of the hole is 12 mm. Focusing lens: D = 30.0 mm, and F = 100.0 mm. Bandpass filter: center wavelength is 1550 nm, and the full width at half-maximum is 40 nm (Thorlabs FB1550-40). Multimode fiber: fiber core is 62.5 µm in diameter.

Fig. 2. (a) PR code 1. (b) The histogram of the detection events when only DFB laser 1 was turned on. (c) Subset of (b). (d) Subset of (e). (e) The histogram of the detection events when all of the lasers were turned on. (f) The cross correlation (Cross-Corr.) of the histogram in (b) with PR code 1. (g) The Cross-Corr. of the histogram in (e) with PR code 1.

Fig. 3. (a) Cross-Corr. when all of the lasers were turned on. (b) Cross-Corr. when DFB lasers 2, 4, 6, 7, and 8 were turned on.

Fig. 4. TOF distribution between the 240 bits of ‘1’ and their corresponding echo photons.

Fig. 5. (a) The average ranging error of eight channels with different accumulated times. (b) The flight time of each channel at the distance of 288.5 m. (c) The ranging error of each channel with the accumulated time of 10 ms.

Fig. 6. (a) The histogram at the distance of 288.5 m when the accumulated time was 10 ms. (b) The histogram at the distance of 288.5 m when the accumulated time was 1 ms. (c) The Cross-Corr. function of laser channels 1, 2, and 3 when the accumulated time was 1 ms.

Fig. 7. (a) Reconstructed 3D image of the objects. (b) The picture of the objects.

Table 1. PR Code Parameters