Improvement of optical signal-to-noise ratio of a high-power pump by stimulated Brillouin scattering in an optical fiber

We propose and demonstrate improvement of optical signal-to-noise ratio of a highpower pump by saturated stimulated Brillouin amplification of a backward seed in a fiber. A 27-dB improvement was obtained for a 1-W pump

Stable multiwavelength erbium-doped random fiber laser

A stable multiwavelength erbium-doped fiber laser (EDFL) based on random distributed feedback (RDFB) is presented. The random EDFL consists of a half-opened linear cavity in which a mirror forms one end, while the other end is connected to RDFB of a 25-km-long single mode fiber. In the laser cavity, the instability caused by the RDFB and cascaded stimulated Brillouin scattering is successfully mitigated by four wave mixing effect in a 2-km-long highly nonlinear fiber. Experimental results indicate the generation of 24 stable laser lines at the pump power of 350 mW. The recorded peak power fluctuation for the laser is less than 0.7 dB in a 60-min duration, illustrating the stability of the multiwavelength random fiber laser

Self-seeded four-wave mixing cascades utilizing fiber Bragg grating

Utilizing fiber Bragg grating (FBG), we demonstrate self-seeded four-wave mixing (FWM) cascades. Larger FWM cascades are produced at higher erbium-doped fiber amplifier (EDFA) output power using a simple scheme. Six channels are generated at the EDFA output power of 252.35 mW. The separation gap of selective dual wavelength is designed at 1.6 nm, following to the wavelength separation of the FBGs used

Dual-wavelength thulium fluoride fiber laser based on SMF-TMSIF-SMF interferometer as potential source for microwave generationin 100-GHz region

A dual-wavelength thulium-doped fluoride fiber (TDFF) laser is presented. The generation of the TDFF laser is achieved with the incorporation of a single modemultimode- single mode (SMS) interferometer in the laser cavity. The simple SMS interferometer is fabricated using the combination of two-mode step index fiber and single-mode fiber. With this proposed design, as many as eight stable laser lines are experimentally demonstrated. Moreover, when a tunable bandpass filter is inserted in the laser cavity, a dual-wavelength TDFF laser can be achieved in a 1.5-μm region. By heterodyning the dual-wavelength laser, simulation results suggest that the generated microwave signals can be tuned from 105.678 to 106.524 GHz with a constant step of �0.14 GHz. The presented photonics-based microwave generation method could provide alternative solution for 5G signal sources in 100-GHz region

Switchable 10, 20, and 30 GHz region photonics-based microwave generation using thulium-doped fluoride fiber laser

In this work, switchable 10, 20, and 30 GHz region photonics-based microwave generation in a fiber laser cavity is proposed and demonstrated. The microwave generation is based on the beating of a dual-wavelength thuliumdoped fluoride fiber laser. With the aid of a micro-air gap in an adapter, single, double, and triple Brillouin spacing can be generated in a single fiber laser cavity without re-routing the cavity. The wavelength spacing of the dual wavelengths that are induced by the single, double, and triple Brillouin spacing are 0.084, 0.166, and 0.254 nm, respectively, at a center wavelength of 1490 nm. In addition, a numerical calculation is performed using MATLAB to prove the generation of microwave signals at 11.34, 22.44, and 34.3 GHz. With the advantage of switchability among the 10, 20, and 30 GHz regions, the proposed photonics-based microwave generation is promising for the advancement of 5G technologies

Radio Frequency Identification (RFID) based cable detection system

Cable theft issues have been known worldwide in the past years therefore this paper discusses how to overcome them by using radio frequency identification (RFID) technology in which the RFID reader can detect the unique identifier (UID) number of the RFID tag that is attached on the cable. The main objective is to develop the RFID-based cable detection system using both software and hardware. Additionally, this system will analyze how the voltage received by the reader can be affected when the distance between tag and reader is varied. The system is developed by using RFID RC522 and Arduino UNO as the main components. The RFID reader will read the data from the RFID tag and will be sent to the Arduino UNO for processing according to the codes that have been programmed into the Arduino UNO. Once processed, the OLED display will display the RFID tag's unique identifier number along with the location of the cable. The range analysis is done by analyzing the distance between reader and tag and the voltage received by the reader. From the results obtained, the trend of range analysis shows that the nearer the distance, the higher the voltage received by the reader. In summary, the proposed solution to the cable theft issues which is RFID based cable detection system could improve the user’s management by reducing the user’s time to locate the cable. However, the system can be improvised by developing a system with the detection range between reader and tag that can reach up to 1m and above

Generation of optical frequency combs with a short photonics crystal fiber

Self-seeded four wave mixing (FWM) cascades with a 50 m long photonics crystal fiber (PCF) as the parametric gain medium are presented. Up to six comb lines are successfully generated when the amplifier output power is set at 519.28 mW. That relatively short length of the PCF enables the proposed scheme to be more compact in size in comparison to a 500 m long of highly nonlinear fiber, utilized in previous work

Fiber optical parametric amplifier with dispersion flattened photonics crystal fiber as a gain medium

A fiber optical parametric amplifier utilizing single continuous wave pump is demonstrated. Gain medium used for parametric amplification is a 50 m long dispersion flattened photonics crystal fiber. The relatively wide bandwidth of pump is able to suppress stimulated Brillouin scattering, allowing the parametric amplifier to operate without modulating the pump. Internal fiber gain as high as 17.1 dB can be achieved with this configuration

Multi-wavelength generation by self-seeded four-wave mixing

A cost effective method of generating multi-wavelength based on the cascaded four wave mixing effect is experimentally demonstrated. The proposed scheme is free from external tunable laser sources and pump modulators, resulting from the use of a broadened linewidth tunable dual wavelength erbium-doped fiber laser as intracavity pump. In this configuration, the number of four wave mixing cascades becomes larger in tandem with the increment of erbium-doped fiber amplifier output power. When its output power is set at 20.57 dBm, six waves having optical signal to noise ratio larger than 10 dB are generated. The six waves are stable with peak power fluctuations less than 1 dB within 30 minutes period and tunable with wavelength spacing ranging from 1.03 nm to 11.31 nm

A Microwave Signal Generation Technique Based on Brillouin-Erbium Fiber Laser

An all-optical microwave signal generator based on multiwavelength Brillouin-Erbium fiber laser (MBEFL) is proposed. The MBEFL unit is designed at fixed wavelength spacing of 0.084 nm, which corresponds to ~10 GHz carrier signal. The underlying mechanism MBEFL unit is by recycling the backscattered Stokes waves into the cavity to generate higher-order Stokes waves. Heterodyning process is then applied to the Brillouin pump (BP) consisted of first-order Brillouin Stokes (BS1) (0.084 nm spacing) and second-order Brillouin Stokes (BS2) (0.168 nm spacing) signals by using a photodetector (PD). The heterodyned outputs are microwave signals at the frequencies of 10.56 GHz and 21.2 GHz, relative to first order and second order Stokes waves, respectively. These microwave signals are experimentally achieved by controlling the EDF pump power where the EDF pump power can be as low as 20 mW