scholarly journals Bitstream Photon Counting Chirped AM Lidar with Digital I/Q Demodulation

2020 ◽  
Author(s):  
Brian Redman
Keyword(s):  
Integrated Circuits ◽  
Single Channel ◽  
Signal To Noise Ratio ◽  
Photon Counting ◽  
Complementary Metal Oxide Semiconductor ◽  
Local Oscillator ◽  
Oxide Semiconductor ◽  
Signal To Noise ◽  
Receiver Architecture ◽  
Noise Ratio

This paper is a follow-up to two previous papers, one introducing the new bitstream Photon Counting Chirped Amplitude Modulation (AM) Lidar (PC-CAML) with the unipolar Digital Logic Local Oscillator (DLLO) concept, and the other paper introducing the improvement thereof using the bipolar DLLO. In that previous work, there was only a single channel of digital mixing of the DLLO with the received photon counting signal. This paper introduces a new bitstream PC-CAML receiver architecture with an in-phase (I) digital mixing channel and a quadrature phase (Q) digital mixing channel for digital I/Q demodulation with the bipolar DLLO to improve the signal-to-noise ratio (SNR) by 3 dB compared to that for the single digital mixing channel with the bipolar DLLO and by 5.5 dB compared to that for the single digital mixing channel with the unipolar DLLO. (patent pending) The bipolar DLLO with digital I/Q demodulation architecture discussed in this paper retains the key advantages of the previous bitstream PC-CAML with a DLLO systems since it also replaces bulky, power-hungry, and expensive wideband RF analog electronics with digital components that can be implemented in inexpensive silicon complementary metal-oxide-semiconductor (CMOS) read-out integrated circuits (ROICs) to make the bitstream PC-CAML with a DLLO more suitable for compact lidar-on-a-chip systems and lidar array receivers than previous PC-CAML systems. This paper introduces the bipolar DLLO with digital I/Q demodulation receiver architecture for bitstream PC-CAML and presents the initial signal-to-noise ratio (SNR) theory with comparisons to Monte Carlo simulation results.

scholarly journals Bitstream Photon Counting Chirped AM Lidar with a Dual Unipolar Signal

2020 ◽  
Author(s):  
Brian Redman
Keyword(s):  
Integrated Circuits ◽  
Phase I ◽  
Signal To Noise Ratio ◽  
Photon Counting ◽  
Complementary Metal Oxide Semiconductor ◽  
Local Oscillator ◽  
Sinusoidal Signal ◽  
Oxide Semiconductor ◽  
Quadrature Phase ◽  
Simulation Results

This paper is a follow-up to three previous papers: the first introducing the new Bitstream Photon Counting Chirped Amplitude Modulation (AM) Lidar (PC-CAML) with the unipolar Digital Logic Local Oscillator (DLLO) concept, the second introducing the improvement thereof using the bipolar DLLO, and the third introducing the improvement of digital In-phase and Quadrature-phase (I/Q) demodulation.In that previous work, the signal was a single unipolar chirped sinusoidal or square wave. This paper introduces a new bitstream PC-CAML transceiver architecture that combines two unipolar chirped signals, referred to as the dual unipolar signal, to form a single bipolar signal in the receiver. (patent pending) This bipolar signal is mixed with the bipolar DLLOs in the in-phase (I) digital mixing and quadrature-phase (Q) digital mixing channels for digital I/Q demodulation for improved signal-to-noise ratio (SNR) compared to that when using a single unipolar signal.The simulation results presented in this paper indicate an SNR improvement for the dual unipolar chirped sinusoidal signal bitstream PC-CAML compared to that of the unipolar chirped sinusoidal signal bitstream PC-CAML (both with bipolar DLLOs and digital I/Q demodulation) of from about 3 dB to about 6 dB for signals below the onset of receiver saturation, and an improvement for maximum achievable SNR of about 13 dB if the receiver is allowed to saturate.The bitstream PC-CAML with a dual unipolar signal and bipolar DLLOs with digital I/Q demodulation architecture discussed in this paper adds complexity to the transmitter and receiver compared to the architectures presented in the previous papers. Whether or not this additional complexity is worth the improved SNR will have to be decided as part of system trade studies for particular systems and their applications.However, the new architecture still retains the key advantages of the previous bitstream PC-CAML architectures since it still replaces bulky, power-hungry, and expensive wideband RF analog electronics in the receiver with digital components that can be implemented in inexpensive silicon complementary metal-oxide-semiconductor (CMOS) read-out integrated circuits (ROICs) to make the bitstream PC-CAML with a DLLO more suitable for compact lidar-on-a-chip systems and lidar array receivers than previous standard PC-CAML systems.This paper introduces the dual unipolar signal and bipolar DLLOs with digital I/Q demodulation transceiver architecture for bitstream PC-CAML, and presents the initial SNR theory with comparisons to Monte Carlo simulation results.

scholarly journals Bitstream Photon Counting Chirped AM Lidar with a Digital Logic Local Oscillator

2019 ◽  
Author(s):  
Brian Redman
Keyword(s):  
Integrated Circuits ◽  
Signal To Noise Ratio ◽  
Logic Gate ◽  
Photon Counting ◽  
Complementary Metal Oxide Semiconductor ◽  
Local Oscillator ◽  
Digital Logic ◽  
Oxide Semiconductor ◽  
Photon Counting Detector ◽  
Analog Electronics

This paper introduces a new concept for the local oscillator (LO) for the Photon Counting Chirped Amplitude Modulation Lidar (PC-CAML). Rather than using a radio-frequency (RF) analog LO applied electronically either in post-detection mixing or via opto-electronic mixing (OEM) at the detector, or applied via pre-detection mixing using an optical intensity modulator as in previous systems, the new method mixes the single-bit binary counts from the photon counting detector with a single-bit binary LO using an AND binary digital logic gate. This type of LO is called the Digital Logic Local Oscillator (DLLO), and the resulting PC-CAML system is a type of bitstream lidar called bitstream PC-CAML (patent pending).The key advantage of the DLLO in the bitstream PC-CAML is that it replaces bulky, power-hungry, and expensive wideband RF analog electronics with single-bit digital logic components that can be implemented in inexpensive silicon complementary metal-oxide-semiconductor (CMOS) read-out integrated circuits (ROICs) to make the bitstream PC-CAML with a DLLO more suitable for compact lidar-on-a-chip systems and lidar array receivers than previous PCCAML systems.This paper introduces the DLLO for bitstream PC-CAML concept, presents the initial signal-to-noise-ratio (SNR) theory with comparisons to Monte Carlo simulation results, and makes suggestions for future work on this concept.

scholarly journals Bipolar Digital Logic Local Oscillator for Bitstream Photon Counting Chirped AM Lidar

2019 ◽  
Author(s):  
Brian Redman
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Signal To Noise Ratio ◽  
Photon Counting ◽  
Local Oscillator ◽  
Digital Logic ◽  
Quantization Noise ◽  
Signal To Noise ◽  
Simulation Results ◽  
Noise Ratio

This paper is a follow-up to a previous paper introducing the new bitstream Photon Counting Chirped Amplitude Modulation (AM) Lidar (PC-CAML) with a Digital Logic Local Oscillator (DLLO) concept. In that previous work, the DLLO was unipolar. In this paper, a new bipolar DLLO for the bitstream PC-CAML is introduced (patent pending). The bipolar DLLO retains the key advantages of the unipolar DLLO for the bitstream PC-CAML since it also replaces bulky, power-hungry, and expensive wideband RF analog electronics with digital components that can be implemented in inexpensive silicon complementary metal-oxide-semiconductor (CMOS) read-out integrated circuits (ROICs) to make the bitstream PC-CAML with a DLLO more suitable for compact lidar-on-a-chip systems and lidar array receivers than previous PC-CAML systems. In addition, the bipolar DLLO improves the electrical power signal-to-noise ratio (SNR) of the bitstream PC-CAML by about 2.5 dB compared to that of the unipolar DLLO as shown by the theoretical and Monte Carlo simulation results presented in this paper. Theoretically, there should be a 3 dB improvement for the bipolar DLLO from the elimination of the signal power loss to the DC component of the intermediate frequency (IF) spectrum that occurs with the unipolar DLLO. However, this improvement is partially offset by a higher quantization noise for the bipolar DLLO compared to that of the unipolar DLLO as explained in this paper.This paper introduces the bipolar DLLO for bitstream PC-CAML concept and presents the initial signal-to-noise ratio (SNR) theory with comparisons to Monte Carlo simulation results.

scholarly journals Up-Conversion Sensing of 2D Spatially-Modulated Infrared Information-Carrying Beams with Si-Based Cameras

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3610
Author(s):  
Adrián J. Torregrosa ◽  
Emir Karamehmedović ◽  
Haroldo Maestre ◽  
María Luisa Rico ◽  
Juan Capmany
Keyword(s):  
Optical Communications ◽  
Near Infrared ◽  
Nonlinear Crystal ◽  
Signal To Noise Ratio ◽  
Low Cost ◽  
Infrared Image ◽  
Complementary Metal Oxide Semiconductor ◽  
Local Oscillator ◽  
Oxide Semiconductor ◽  
Free Space Optical

Up-conversion sensing based on optical heterodyning of an IR (infrared) image with a local oscillator laser wave in a nonlinear optical sum-frequency mixing (SFM) process is a practical solution to circumvent some limitations of IR image sensors in terms of signal-to-noise ratio, speed, resolution, or cooling needs in some demanding applications. In this way, the spectral content of an IR image can become spectrally shifted to the visible/near infrared (VIS/NWIR) and then detected with silicon focal plane arrayed sensors (Si-FPA), such as CCD/CMOS (charge-coupled and complementary metal-oxide-semiconductor devices). This work is an extension of a previous study where we recently introduced this technique in the context of optical communications, in particular in FSOC (free-space optical communications). Herein, we present an image up-conversion system based on a 1064 nm Nd3+: YVO4 solid-state laser with a KTP (potassium titanyl phosphate) nonlinear crystal located intra-cavity where a laser beam at 1550 nm 2D spatially-modulated with a binary Quick Response (QR) code is mixed, giving an up-converted code image at 631 nm that is detected with an Si-based camera. The underlying technology allows for the extension of other IR spectral allocations, construction of compact receivers at low cost, and provides a natural way for increased protection against eavesdropping.

scholarly journals Three-Dimensional Imaging via Time-Correlated Single-Photon Counting

2020 ◽  
Vol 10 (6) ◽  
pp. 1930
Author(s):  
Chengkun Fu ◽  
Huaibin Zheng ◽  
Gao Wang ◽  
Yu Zhou ◽  
Hui Chen ◽  
...  
Keyword(s):  
3D Imaging ◽  
Single Photon ◽  
Signal To Noise Ratio ◽  
Photon Counting ◽  
Three Dimensional ◽  
Similarity Index ◽  
Signal To Noise ◽  
Single Photon Counting ◽  
Imaging Results ◽  
Noise Ratio

Three-dimensional (3D) imaging under the condition of weak light and low signal-to-noise ratio is a challenging task. In this paper, a 3D imaging scheme based on time-correlated single-photon counting technology is proposed and demonstrated. The 3D imaging scheme, which is composed of a pulsed laser, a scanning mirror, single-photon detectors, and a time-correlated single-photon counting module, employs time-correlated single-photon counting technology for 3D LiDAR (Light Detection and Ranging). Aided by the range-gated technology, experiments show that the proposed scheme can image the object when the signal-to-noise ratio is decreased to −13 dB and improve the structural similarity index of imaging results by 10 times. Then we prove the proposed scheme can image the object in three dimensions with a lateral imaging resolution of 512 × 512 and an axial resolution of 4.2 mm in 6.7 s. At last, a high-resolution 3D reconstruction of an object is also achieved by using the photometric stereo algorithm.

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