- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
INVESTIGATION OF FREQUENCY NOISE AND SPECTRUM LINEWIDTH IN SEMICONDUCTOR OPTICAL AMPLIFIER
摘要： The characteristics of FM noise and linewidth of semiconductor optical amplifier without facet mirrors were theoretically analyzed and experimentally confirmed. The concept of discrete longitudinal mode for the spontaneous emission was introduced as the basis of quantum mechanical characteristics, allowing the quantitative examination of noise sources. The continuously broaden output spectrum profile of the amplified spontaneous emission (ASE) was well explained as a spectrum broadening of each longitudinal mode. We found that the linewidth of the inputted signal light hardly changes by the optical amplification in the SOA. The FM noise increases proportional to square value of the noise frequency and less affected by the electron density fluctuation, the linewidth enhancement factor and the ASE. The higher FM noise in the higher noise frequency is caused by the intrinsic phase fluctuation on the optical emission. The characteristics of the linewidth and the noise frequency dependency were experimentally confirmed.
关键词： noise,frequency noise,Optical fiber communication,linewidth,semiconductor optical amplifier
更新于2025-09-23 15:22:29
-
[IEEE 2018 IEEE 7th International Conference on Photonics (ICP) - Kuah (2018.4.9-2018.4.11)] 2018 IEEE 7th International Conference on Photonics (ICP) - Passive Element Fault Analysis at the Last Mile of the FTTH Network in Malaysia
摘要： The optical transceiver performance for GPON FTTH (OLTTx and ONURx) for 300 live subscribers at legacy area has been monitored hourly for a duration of four months. The optical performance is then plotted against its faults due to the passive element at the last mile of the GPON FTTH network. The results show that the fault rate for aerial type of fiber distribution (FDP) is higher (1.3%) than building, street cabinet and underground FDP types. More than 65% of the faults are contributed by optical fibers (drop fibers) and the rest is due to fiber connectors. The optical power received (ONURx) spectrum shows three types of patterns before disconnection; sudden disconnection, fluctuation and degradation of ONURx. This study provides preliminary information necessary for developing the passive element fault prediction for GPON FTTH at the last mile of the network.
关键词： link loss,GPON FTTH network,optical transmit power: receive power,optical fiber,signals degradation,passive elements
更新于2025-09-23 15:22:29
-
Cross correlation peak-seeking technique of BOTDR based on the incomplete Brillouin spectrum
摘要： Considered the limitation of sweeping frequency technique, Brillouin optical time domain reflectometer (BOTDR) can only perceive slow external interference. It greatly limits the scope of application. For perceiving rapid external interference, a method of cross correlation peak-seeking technique based on incomplete Brillouin spectrum (IBS) is proposed, and the feasibility of the method is verified under the background of the monitoring of sound barriers along the high-speed railway. The numerical simulation results indicate that the probability that obtains an accurate peak frequency error within the 0.50 MHz can reach 49/50, when frequency interval for sweeping is 5 MHz and number of splicing IBS is 80. In addition, to select the optimal parameters of the system, we also take a further analysis on the effect of the splicing times and the frequency interval for sweeping on the peak detection accuracy. This method is significant to extend the application of BOTDR from slow changing fields to rapid changing fields.
关键词： Optical time domain reflectometry,Brillouin scattering,Optical fiber measurement applications
更新于2025-09-23 15:22:29
-
[IEEE 2018 International Conference on Intelligent and Innovative Computing Applications (ICONIC) - Mon Tresor, Plaine Magnien, Mauritius (2018.12.6-2018.12.7)] 2018 International Conference on Intelligent and Innovative Computing Applications (ICONIC) - Atmospheric Effects on Free Space Optics Wireless Communication: Applications and Challenges
摘要： Demand for data and multi-media services in recent times has really grown and it is expected to grow more in the next decade with application ranges from high speed real-time/live streaming to live video-conferencing, and so the demand for new and richer data services to meet up with the new and more advanced applications. In other to meet up with these great users’ expectations, there is a need to explore other viable access network technologies that can offer services beyond what is already in the offering. Free space optical (FSO) communication system is the predominant choice to replace existing wireless technology with great availability of link capacity and huge bandwidth to meet the user’s expectation of the 21st century. This system is reliant on optics signal transmitted in a free space channel, hence termed FSO. This type of communication does not require any licenses for its operation and offers many features being the low-start up and operational cost, rapid development and high fiber-like bandwidth. FSO uses line-of-sight path for the communication between two points and beam of light to provide optical connection that can send and receive video, voice and data information. This technology provides a massive and unregulated bandwidth where a data rate in excess of 100Gbit/s is achievable over a distance of 1-4km. However, it suffers from degradation in the signal quality due to its susceptibility to atmospheric channel impairments which limits its wide deployment and quality of services. This paper explores the FSO system, atmospheric effects of implementing this system and mitigating techniques.
关键词： free space optical fiber-like,atmospheric channel,real-time,multi-media
更新于2025-09-23 15:22:29
-
Compensation of the fluctuations of differential delay for frequency transfer in DWDM networks
摘要： This paper investigates the possibility of improving the stability of radio frequency transfer in telecommunication Dense Wavelength Division Multiplexing (DWDM) fiber optic networks. As it has been identified, the dispersion compensation in these networks, cause fibers (DCFs), frequently used temperature-induced substantial differential delay, whose fluctuations have the most significant impact on deterioration of the stability of frequency transfer. The authors present a method that allows achieving significant improvement of the long-term stability of frequency transfer. The developed method is based on modeling the impact of DCFs with the help of remotely accessible temperature sensors factory-installed by the manufactures in DCF modules. The effectiveness of the proposed solution has been tested on three different long haul routes (up to 1550 km), set up in the operational PIONER network.
关键词： frequency transfer,alien wavelength,DWDM network,optical fiber
更新于2025-09-23 15:22:29
-
Reflective SPR Sensor for Simultaneous Measurement of Nitrate Concentration and Temperature
摘要： In this paper, a reflective fiber optic sensor based on surface plasmon resonance (SPR) was proposed to measure nitrate concentration and temperature simultaneously. The sensor adopted reflective structure, and used gold film as metal film for exciting SPR. Then, Cu-nanoparticles/carbon nanotubes composite film was used as sensitive material to measure nitrate concentration, and it was coated on the surface of the gold film by the dip coating method. Finally, polydimethylsiloxane was coated on part of the sensing probe to produce two independent resonance dips in the output spectrum. When the nitrate concentration and temperature changed, the two resonance dips would all move, but with different sensitivities. By monitoring the wavelength shifts of the two dips, the nitrate concentration and temperature could be measured simultaneously with using the dual-wavelength matrix method. Experimental results demonstrated that the measurement sensitivity of the nitrate concentration could reach 3.25 nm/lg[M], and the temperature measurement sensitivity was ?2.02 nm/°C. Moreover, the sensor had high-mechanical strength and was easy to package, which could be applied to remote measurement field.
关键词： reflective surface plasmon resonance (SPR),optical fiber sensor,Nitrate concentration,simultaneous measurement,temperature
更新于2025-09-23 15:22:29
-
Implications of Distributed Link Polarization Dependent Loss on Bit-Wise Achievable Information Rates for Probabilistically Shaped and Uniform DP 64-QAM
摘要： The statistical behaviours of bit-wise achievable information rates (BW AIRs) and effective signal-to-noise ratios (SNRs) due to polarization dependent loss (PDL) are experimentally characterized for probabilistically shaped and uniform dual-polarization 64-ary quadrature amplitude modulation (DP 64-QAM) with a bit rate of 250 Gb/s. A single-span recirculating loop is used to emulate distributed link PDL. Histograms for the BW AIR and effective SNR following offline signal processing resemble shifted, mirror-image Maxwell probability density functions for both constellations and two different per-loop PDL values. For a transmission distance of 1200 km and a per-loop PDL of 1.3 dB, the outage probabilities for the shaped and uniform constellations are estimated to be 1.1 × 10?3 and 4.4 × 10?1, respectively. Moreover, for an outage probability ≤ 4.0 × 10?3, the increase in transmission distance due to shaping is reduced by 50% compared to that for PDL free transmission.
关键词： Probabilistic shaping,coherent optical fiber transmission systems,polarization dependent loss
更新于2025-09-23 15:22:29
-
Theoretical analysis of seawater depth and temperature measurement with C-type micro-structured fiber grating
摘要： A new C-type micro-structured grating structure was proposed for simultaneous measurement of depth and temperature in seawater. Because wedge-shaped defects got introduce, high birefringence was excited at fiber core of grating. Thermo sensitive materials filled in micro pores to improve the sensitivity of temperature. Then we established a mathematical model of birefringence effect in C-type structure. This work analyzed stress distribution in all directions under two disturbances. In pressure and temperature environment, reflection peaks in two-polarization states separated with a large offset. Two characteristic parameters:λB, y ? λB, x, λB, y + λB, x were proposed for corresponding measurement. Structural parameters got optimize for better performance. Calculated output signals had high sensitivity and linearity under pressure range of 0–10 MPa and temperature range of 0–40 °C. λB, y ? λB, x mainly responded to pressure, which got sensitivity ?1.709 nm/MPa. While temperature mainly influenced λB, y + λB, x and the obtained temperature sensitivity was 1.054 nm/°C. This structure would have a great potential application due to the mature demodulation technique of grating signal.
关键词： Seawater measurement,Depth measurement,Temperature sensor,C-type micro-structured grating,Optical fiber sensor
更新于2025-09-23 15:22:29
-
Experimental and numerical investigation to rationalize both near-infrared and mid-infrared spontaneous emission in?Pr3+ doped selenide-chalcogenide fiber
摘要： This contribution reports on detailed experimental and numerical investigations of both near-infrared (NIR) and mid-infrared (MIR) photoluminescence obtained in praseodymium trivalent ion doped chalcogenide-selenide glass fiber. The experimental analysis allows for the identification of the radiative transitions within the praseodymium ion energy level structure to account for the photoluminescent behavior. Numerical analysis is carried out using the rate equations' approach to calculate the level populations. The numerical analysis provides further insight into the nature of the radiative transitions in the Pr3+ ion doped chalcogenide-selenide glass and allows for the identification of the electronic transitions, which contribute to the observed photoluminescence. The numerical results agree well with the experimental results.
关键词： chalcogenide glass fibers,optical fiber modelling,lanthanide doped fibers
更新于2025-09-23 15:22:29
-
Photomedicine - Advances in Clinical Practice || Light-Emitting Woven Fabric for Treatment with Photodynamic Therapy and Monitoring of Actinic Keratosis
摘要： A successful photodynamic therapy (PDT) requires a specific photosensitizer, oxygen and light of a specific wavelength and power. Today photodynamic therapy (PDT) is administered to patients with light-emitting diode (LED) panels. These panels deliver a non-uniform light distribution on the human body parts, as the complex human anatomy is not a flat surface (head vertex, hand, shoulder, etc.). For an efficient photodynamic therapy (PDT), a light-emitting fabric (LEF) was woven from plastic optical fibers (POF) aiming at the treatment of dermatologic diseases such as actinic keratosis (AK). Plastic optical fibers (POF) (Toray, PGR-FB250) have been woven in textile in order to create macro-bendings, and thus emit out the injected light directly to the skin. The light intensity and light-emitting homogeneity of the LEF were improved thanks to Doehlert Experimental Design. During the treatment with PDT, the photosensitizers were activated in the cancerous cells. These cells may be visualized, as they show a characteristic fluorescence under UV light, which is called fluorescence diagnosis (FD). Therefore, it is proposed to modify the developed LEF for PDT to measure the fluorescence amount. For this aim, a part of POFs was cut out to observe the quantity of light that could be collected while the LEF was connected to a light source. The first prototypes showed the possibility of the illumination with the same LEF without losing the efficiency but also imaging the collected light.
关键词： fluorescence diagnosis (FD),weaving,light emitting fabric (LEF),plastic optical fiber (POF),photodynamic therapy (PDT)
更新于2025-09-23 15:22:29