Heterodyne detection of an optical signal after one-way propagation on an atmospheric path

1968 ◽  
Vol 56 (1) ◽  
pp. 126-128 ◽  
Author(s):  
R.D. Rosner
Keyword(s):  
Optical Signal ◽  
Heterodyne Detection ◽  
Atmospheric Path

Heterodyne detection of partially coherent optical signal

1981 ◽  
Vol 64 (9) ◽  
pp. 97-103
Author(s):  
Takashi Takenaka ◽  
Nobuhiro Saga ◽  
Otozo Fukumitsu
Keyword(s):  
Optical Signal ◽  
Heterodyne Detection ◽  
Partially Coherent

scholarly journals Optoelectronic mixer with a photoconductive switch for 1550 nm wavelengths

2018 ◽  
pp. 16-21
Author(s):  
Róbert Horváth ◽  
Jean-François Roux ◽  
Julien Poëtte ◽  
Béatrice Cabon
Keyword(s):  
Data Stream ◽  
Continuous Wave ◽  
Detection System ◽  
Local Oscillator ◽  
Optical Signal ◽  
Wide Frequency Range ◽  
Electrical Signal ◽  
Heterodyne Detection ◽  
Photoconductive Switch ◽  
Semiconductor Laser Diode

We demonstrate an optoelectronic mixer based on an ultrafast InGaAs photoconductive switch and its use in an innovative heterodyne detection system for Radio over Fibre transmission. The advantage of the proposed switch is its relatively flat response curve in a wide frequency range up to 67 GHz. Two mixing schemes are presented through I-Q modulated data-stream down-conversion. The data can modulate either the electrical signal or the optical signal. In case the electrical signal is modulated, a mode-locked semiconductor laser diode is used as an optical local oscillator at the self-oscillating frequency of 24.5 GHz. The InP based quantum-dash mode-locked laser emitting in the 1570 nm wavelength range is stabilized by a feedback loop and shows a low phase noise in order to increase the mixing performances of the detection apparatus. In a second experiment, the photoconductive switch is combined with a continuous wave laser to demonstrate the feasibility of down converting an optically provided data-stream with an electrical local oscillator.

scholarly journals Implementation of Optical Coherent Communication System between Two Computers

2010 ◽  
Vol 7 (1) ◽  
pp. 41-47
Author(s):  
Baghdad Science Journal
Keyword(s):  
Optical Fiber ◽  
Communication System ◽  
Signal To Noise Ratio ◽  
Single Mode ◽  
Local Oscillator ◽  
Optical Signal ◽  
Coherent Detection ◽  
Heterodyne Detection ◽  
Laser Source ◽  
Coherent Communication

This work represents implementation and investigation of optical coherent communication system between two computers. A single mode optical fiber is selected as transmission medium. The data are sent via the RS-232 standard interface with a bit rate of 9.6 kbps from personal computer (PC1) by line receive to convert the data from electrical levels (-12/+12 V) into TTL level (0/5 V). The modulation of this data was accomplished by internal modulation using laser diode type (HFCT-5208M) 1310 nm wavelength. The optical D-coupler was used to combine the optical signal that come from laser source with optical signal of laser local oscillator (OTS-304XI) at 1310/1550 nm wavelength to obtain coherent (homodyne and heterodyne) detection respectively. A PIN photodetector (HFCT-5208M) is used. Calculations of Signal to Noise Ratio (SNR) and Bit Error Rate (BER) for coherent detection were measured at different length of the optical fiber. Result show that high SNR and low BER for heterodyne detection than for homodyne detection.

Heterodyne detection of partially coherent optical signal

1981 ◽  
Vol 64 (9) ◽  
pp. 97-103
Author(s):  
Takashi Takenaka ◽  
Nobuhiro Saga ◽  
Otozo Fukumitsu
Keyword(s):  
Optical Signal ◽  
Heterodyne Detection ◽  
Partially Coherent

scholarly journals Development of an Optical System for Non-Contact Type Measurement of Heart Rate and Heart Rate Variability

2021 ◽  
Vol 4 (3) ◽  
pp. 48
Author(s):  
Jyoti Gondane ◽  
Meena S. Panse
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Vibration Frequency ◽  
Optical Signal ◽  
Test Subject ◽  
Coherent Detection ◽  
Detection Technique ◽  
Heterodyne Detection ◽  
Accurate Information ◽  
Detection Techniques

Self-mixing optical coherent detection is a non-contact measurement technique which provides accurate information about the vibration frequency of any test subject. In this research, novel designs of optical homodyne and heterodyne detection techniques are explained. Homodyne and heterodyne setups are used for measuring the frequency of the modulated optical signal. This technique works on the principle of the optical interferometer, which provides a coherent detection of two self-mixing beams. In the optical homodyne technique, one of the two beams receives direct modulation from the vibration frequency of the test subject. In the optical heterodyne detection technique, one of the two optical beams is subjected to modulation by an acousto-optics modulator before becoming further modulated by the vibration frequency of the test subject. These two optical signals form an interference pattern that contains the information of the vibration frequency. The measurement of cardiovascular signals, such as heart rate and heart rate variability, are performed with both homodyne and heterodyne techniques. The optical coherent detection technique provides a high accuracy for the measurement of heart period and heart rate variability. The vibrocardiogram output obtained from both techniques are compared for different heart rate values. Results obtained from both optical homodyne and heterodyne detection techniques are compared and found to be within 1% of deviation value. The results obtained from both the optical techniques have a deviation of less than 1 beat per minute from their corresponding ECG values.

USE OF A CO2LASER AS A LOCAL OSCILLATOR FOR A 10 MICRON HETERODYNE DETECTION

1987 ◽  
Vol 48 (C7) ◽  
pp. C7-569-C7-571
Author(s):  
A. DELAHAIGUE ◽  
D. COURTOIS ◽  
C. THIEBEAUX ◽  
H. LE CORRE
Keyword(s):  
Local Oscillator ◽  
Heterodyne Detection

Optical Signal Processing Using Nonlinear Period-One Dynamics of Semiconductor Lasers

2014 ◽  
Vol 1 ◽  
pp. 462-465
Author(s):  
Sheng-Kwang Hwang ◽  
Sze-Chun Chan ◽  
Yu-Han Hung ◽  
Shiuan-Li Lin ◽  
Cheng-Hao Chu
Keyword(s):  
Signal Processing ◽  
Semiconductor Lasers ◽  
Optical Signal Processing ◽  
Optical Signal

Measurement of High Speed Polarization Change of Optical Signal through an OPGW Caused by Serge Current

2016 ◽  
Vol 136 (7) ◽  
pp. 887-892
Author(s):  
Ikuo Yamashita ◽  
Shun Morimura ◽  
Hitoshi Murai ◽  
Osamu Ogawa ◽  
Masahiro Kurono
Keyword(s):  
High Speed ◽  
Optical Signal ◽  
Polarization Change
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