The 5G technology is a promising technology to cope with the increasing demand for higher data rate and quality of service. In this paper, two proposed techniques are implemented for multiple input multiple output (MIMO) self-heterodyne OFDM system t...
A useful method for eliminating the detrimental effect of laser frequency instability on Brillouin signals by employing the self-heterodyne detection of Rayleigh and Brillouin scattering is presented. From the analysis of Brillouin scattering spectra...
A polarization-insensitive recirculating delayed self-heterodyne method (PI-RDSHM) is proposed and demonstrated for the precise measurement of sub-kilohertz laser linewidths. By a unique combination of Faraday rotator mirrors (FRMs) in an interferome...
To evaluate the impact of signal-to-noise ratio (SNR) on short-delay self-heterodyne laser linewidth measurement, we systematically compare the peak–valley method (PVM) and the power spectral equalization (PSE) method across a 20–80 dB SN...
Delayed self-heterodyne/homodyne measurements based on an unbalanced interferometer are the most used methods for measuring the linewidth of narrow-linewidth lasers. They typically require the service of a delay of six times (or greater) than the las...
We experimentally demonstrate a fiber laser with different linewidths based on self-injection locking (SIL) and the stimulated Brillouin scattering effect. Based on the homemade fiber laser, the error origin, resolution, and applicable range of delay...
The broad-frequency response and nanometer-range displacements of ultrasound detection are essential for the characterization of small cracks, structural health monitoring and non-destructive evaluation. Those perturbations are generated at sub-nano-...
Narrow-linewidth lasers mainly depend on the development of advanced laser linewidth measurement methods for related technological progress as key devices in satellite laser communications, precision measurements, ultra-high-speed optical communicati...
Although laser heterodyne interferometric sensing systems offer exceptional theoretical resolution, practical precision is constrained by intractable nonlinear errors stemming from optical imperfections. Conventional compensation methods suffer from...
Linewidth measurements of a distributed feedback (DFB) fibre laser are made using delayed self heterodyne interferometry (DHSI) with both Mach-Zehnder and Michelson interferometer configurations. Voigt fitting is used to extract and compare the Loren...
Here, we report on a simplified laser frequency noise measurement technique employing an acousto-optic modulator, a delay line, and a real-time oscilloscope. The technique is a slight modification of the typical delayed heterodyne method. Instead of...
An accurate, easy setup, low-cost, and time-saving method for measuring glucose concentration was proposed. An all-grating-based glucose concentration measurement system contained moving-grating-based heterodyne interferometry and a grating-based sel...
Heterodyning by a phase stable reference electric field is a well known technique to amplify weak nonlinear signals. For short wavelength, the generation of a reference field in front of the sample is challenging because of a lack of suitable beamspl...
We design, fabricate and experimentally demonstrate a novel generic method to detect flow rates and precise changes of flow velocity in microfluidic devices. Using our method we can measure flow rates of ~2 mm/s with a resolution of 0.08 mm/s. The o...
In this work, we studied the propagation of ultrasonic waves of lysozyme solutions characterized by different degrees of aggregation and networking. The experimental investigation was performed by means of the transient grating (TG) spectroscopy as a...
A single-frequency narrow linewidth green laser at 510 nm is a vital component for the study of Cesium Rydberg atoms. Here, we demonstrate a 510 nm laser based on single-pass second-harmonic generation (SHG) and sum-frequency generation (SFG) via wav...
Narrow-linewidth lasers have a high spectral purity, long coherent length, and low phase noise, so they have important applications in atomic clocks, precision measurement, and quantum computing. We inject a transmitted laser from a narrow-linewidth...
The Erbium “random” laser, based on the artificial Rayleigh fiber, has been comparatively studied in detail under two different pump conditions: 974.5 and 1485 nm pumping wavelengths. The artificial Rayleigh 7-m-long fiber was used as a l...
To narrow spectral linewidth, stabilize longitudinal mode and improve output performance of a 1064 nm distributed feedback (DFB) semiconductor laser, we design and fabricate a laser module adopting fiber Bragg grating (FBG) external-cavity feedback a...
This work proposes and experimentally demonstrates a high-performance polarization space parity-time (PT) symmetric fiber ring laser to achieve a low-noise, narrow-linewidth, and highly stable single-longitudinal-mode output. The gain/loss and coupli...
This paper presents experimental evidence regarding a novel switchable dual-wavelength thulium-doped fiber laser (TDFL). Wavelength switching is achieved by combining a polarization-maintaining fiber Bragg grating (PM-FBG) with a polarization control...
In the field of inter-satellite laser communication, achieving high-quality communication and compensating for the Doppler frequency shift caused by relative motion necessitate lasers with narrow linewidths, low phase noise, and the ability to achiev...
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 techniqu...
We present our theoretical model and experimental results on the extreme linewidth narrowing of an erbium-doped fiber distributed feedback (DFB) laser due to an additional random DFB via Rayleigh backscattering in a long single-mode fiber connected t...
To address the issues of subcarrier orthogonality loss and inter-carrier interference (ICI) caused by carrier frequency offset (CFO), this paper proposes and experimentally validates a frequency offset estimation (FOE)-assisted dual-domain Transforme...
We report on high-order harmonic (HHG) two-source interferometry (TSI) in molecular gases. We used a 0-\(\pi\) phase plate to create two bright spots at the focus of a lens by converting a Gaussian laser beam into a TEM please define \(_{01}\) Transv...
This paper presents the design and measurement of an IEEE 802.11ad standard compatible RF transceiver for 60 GHz wireless communication systems. In addition to the traditional half-duplex (HD) mode, this work supports full-duplex (FD) operations to d...
Since the turn of the millennium, the development and commercial availability of optical frequency combs has led to a steadily increase of worldwide installed frequency combs and a growing interest in using them for industrial-related metrology appli...
Conventional single-mode fiber (SMF) Brillouin optical time-domain reflectometry (BOTDR) suffers from a low signal-to-noise ratio (SNR) and severe sensing reliability due to the influence of the stimulated Brillouin scattering threshold and bend loss...
Compact spatial heterodyne spectroscopy (SHS) is useful for atmospheric remote sensing, but repeated interferogram acquisition alone does not guarantee stable recovered spectral intensity. An intensity-preserving framework based on self-calibrated qu...
The Total Carbon Column Observing Network (TCCON) and the Infrared Working Group of the Network for the Detection of Atmospheric Composition Change (NDACC-IRWG) are two ground-based networks that provide the retrieved concentrations of up to 30 atmos...