China
Africa
Explore chapters and articles related to this topic
Optical Fiber Sensing Solutions
Published in Krzysztof Iniewski, Ginu Rajan, Krzysztof Iniewski, Optical Fiber Sensors, 2017
Yuliya Semenova, Gerald Farrell
The signal at the output port of the fiber coupler is a result of interference between the beams polarized along the slow axis and the fast axis. The phase of the interference is given as δSL=2πλBL where B = |nf−ns| is the birefringent coefficient of the sensing fiberL is the length of the fibernf and ns are the effective indices of the fast and slow modes
Optical Fiber and Its Application in Communication—An Overview
Published in Tarun Kumar Gangopadhyay, Pathik Kumbhakar, Mrinal Kanti Mandal, Photonics and Fiber Optics, 2019
A simple 2 × 2 fused-fiber coupler consists of two input ports and two output ports. This coupler can be fabricated by twisting together, melting and pulling two single mode fibers so they get fused together over a uniform section of length L. In the coupling region, the ratio r/λ decreases, and consequently, V-parameter decreases and a larger part of input field propagates outside the core of the fiber (increase evanescent field) and is recoupled into the other fiber core. This mechanism is responsible for the division of optical power in the coupler. Now we consider P0 is input power, P1 is throughput power, P2 is coupled power. Assuming the coupler is loss-less, the coupled power P2 from fiber-1 to fiber-2 over an axial distance z is given by () P2=P0sin2(κz)
Full Coupled-Mode Theory
Published in Le Nguyen Binh, Guided Wave Photonics, 2016
An optical fiber coupler is a device that distributes the light beam guided along a fiber into two or more branches. It can be used as a power divider, a wavelength-division multiplexer (WDM), and an optical switch. As the applications of photonic crystal fibers are increased, MOF couplers will be necessary in optical communications. Optimized DC-MOF structure for coupling is derived in this paper. Structures that are promising for light confinement when multiple defects are presented in MOF are also indicated.
Artificial neural network (ANN) for dispersion compensation of spectral domain – optical coherence tomography (SD-OCT)
Published in Instrumentation Science & Technology, 2022
Dan Yang, Wenxin Guo, Tonglei Cheng, Zhulin Wei, Bin Xu
In order to better verify the developed method, SD-OCT system experimental platform was constructed that was a combination of single-mode fiber and free-space optics as shown in Figure 11, The SD-OCT system uses an amplified spontaneous emission broadband light source (ASE, OS8143-23) to provide broadband light from 1520 nm to 1610 nm. A 50:50 optical fiber coupler (TW1550R5A2, Thorlabs, USA) splits the beam through a collimator (F280FC-1550, Thorlabs, USA) and focuses it on a mirror and sample by a quartz lens (GCL-010820, Daheng, China). The reflected reference light was coupled with the sample light and recorded by a spectrometer (OSA, AQ6375B, Yokogawa, Japan). The spectrometer recorded from 1200 to 2400 nm with a resolution of 0.05 nm and transmits the signal to the computer.
Characterization of the Buoyant Jet above a Catalytic Combustor Using Wavelength Modulation Spectroscopy
Published in Combustion Science and Technology, 2019
Torrey R. S. Hayden, Nicholas T. Wimer, Caelan Lapointe, Jason D. Christopher, Siddharth P. Nigam, Aniruddha Upadhye, Mark Strobel, Peter E. Hamlington, Gregory B. Rieker
A schematic of the experimental setup is shown in Figure 5. The sensor contains two NEL DFB lasers centered at 1391.7 nm and 1468.9 nm. An ILX Laser Diode Controller (LDC) sets the center wavelength of each laser by adjusting current and temperature of each laser individually. Using external voltage inputs, the LDC also modulates the intensity and wavelength. A National Instruments PCI 6110 data-acquisition board connected to a National Instruments 2110 connector box generates voltage waveforms that are applied to the LDC. Each laser drive signal is composed of a sine wave at 500 Hz to tune the wavelength over the absorption feature, as well as a fast sine wave for WMS. This fast sine wave is at 130 kHz with a modulation depth of 0.016 nm (0.083 cm−1) for the 1392 nm laser and at 170 kHz with a modulation depth of 0.020 nm (0.093 cm−1) for the 1469 nm laser. The slow frequency was chosen to capture any burner transients while fast modulation frequencies were selected to provide sufficient frequency spacing for the lock-in amplifier to isolate the 1f and 2f signals of interest while taking advantage of high-frequency 1/f noise reduction. Light from the two lasers is multiplexed onto a single fiber using a 50/50 fiber coupler so that the two lasers simultaneously pass through the gas sample along the same path.
Sensitive determination of arginine based on hydrogen bonding by a surface plasmon resonance (SPR) sensor
Published in Instrumentation Science & Technology, 2020
The probe fixed on the lifting arm of the dip coater was connected to the light source and the micro-spectrometer through a 1 × 2 fiber coupler. The light from the light source was transferred to the spectrometer via the reflection of the reflective end face of the optical fiber probe. The mechanical arm conveniently controlled the depth and stability of the inserted solution during this detection process.