Jing-Heng Chen

Stable and Tunable Single-Longitudinal-Mode Erbium-Doped Fiber Triple-Ring Laser With Power-Equalized Output

In this demonstration, we propose and investigate a stable and tunable single-longitudinal-mode (SLM) erbium-doped fiber (EDF) ring laser structure. Here, in order to achieve the SLM output, the “eye-type” triple-ring scheme is designed in this EDF laser to suppress the densely spaced longitudinal modes. In the measurement, the output power and optical-signal-to-noise ratio (OSNR) are between 8.35 and 8.92 dBm and 33.2 and 35.7 dB, respectively, in the wavelength range of 1530 to 1560 nm. The proposed EDF laser architecture not only has free tuning step but provides stabilized and flattened output power spectrum as well.

Utilizing simple FBG-based erbium-doped fiber architecture for remote temperature sensing

In this work, we demonstrate experimentally an erbium-doped fiber (EDF) ring laser structure for remote temperature sensing by using fiber Bragg gratings (FBGs) in C-band. Based on the proposed EDF laser configuration, the remote temperature sensing distance is achieved at 50 km. Here, ten FBGs are employed at the remote side for temperature sensing. By tuning the optical tunable filter (TF), the corresponding Bragg wavelength from each FBG can be monitored in the proposed EDF laser. As a result, in the temperature range from 20 to 82 °C, the maximum drift of Bragg wavelength can be detected at 0.84 nm.

Preparation of bismuth oxide photocatalyst and its application in white-light LEDs

Bismuth oxide photocatalysts were synthesized and coated on the front surface of phosphor-converted white light-emitting diodes to produce a safe and environmentally benign lighting source. Bismuth oxide photocatalyst powders were synthesized with a spray pyrolysis method at 500°C, 600°C, 700°C, and 800°C. Using the absorption spectrum in the blue and UV regions of the bismuth oxide photocatalysts, the blue light and UV leakage problems of phosphor-converted white LEDs can be significantly reduced. The experimental results showed that bismuth oxide photocatalyst synthesized at 700°C exhibited the most superior spectrum inhibiting ability. The suppressed ratio reached 52.33% in the blue and UV regions from 360 to 420 nm. Related colorimetric parameters and the photocatalyst decomposition ability of fabricated white-light LEDs were tested. The CIE chromaticity coordinates (x, y) were (0.349, 0.393), and the correlated color temperature was 4991K. In addition, the coating layer of photocatalyst can act as an air purifier and diffuser to reduce glare. A value of 66.2 ± 0.60 ppmv of molecular formaldehyde gas can be decomposed in 120mins.

Employing dual-saturable-absorber-based filter for stable and tunable erbium-doped fiber ring laser in single-frequency

In this demonstration, a stable and wavelength-tunable erbium-doped fiber (EDF) ring laser using dual-saturable-absorber-based (DSAB) filter inside loop cavity is proposed and experimentally investigated. The proposed DSAB filter not only can filter the side-mode in single-frequency output, but also can obtain the flattened output power spectrum within 1 dB variation in the effectively range of 1529 to 1563 nm. In addition, the output stabilities of wavelength and power are also measured experimentally and discussed.

Mechanical Properties Measurement of Polymer Films by Bulge Test and Fringe Projection

This paper aims at determining the mechanical properties such as Poisson ratio, biaxial modulus, and residual stress of polymer membranes using the bulge test and fringe projection. Under this idea, a bulge test apparatus has been developed for robust usage, under the room temperature, in industrial environments that are usually noisy and full of all kinds of vibrations. A setup of the bulge test, consisting of single chips and digital on-off valves, was used to achieve automatic precision control of pressure application to gas chamber with a circular polyimide (PI) test film fixed on the opening of it. A deformed image was then obtained via fringe projections with a series of optical apparatuses, and a 3D membrane deformation distribution was further achieved from this deformed image by some image processes that are chiefly through wavelet transformation and phase expansion. With the measurements of maximum membrane deformation versus applied pressure and given the Young’s modulus of test membrane, we could further calculate the Poisson ration (and then biaxial modulus) and residual stress of the film. Also, the measurements were validated to be highly accurate by comparison with a finite element analysis.

Simple erbium-doped dual-ring fiber laser configuration for stable and tunable dual-wavelength output

We propose and experimentally investigate a stable and tunable dual-wavelength erbium-doped fiber (EDF) dual-ring laser scheme. Here, two tunable bandpass filters (TBFs) are used inside the dual-ring gain cavity to generate dual-wavelength lasing. And, due to the gain competition of the EDF gain cavity, the mode-spacing (Δλs) of lasing dual-wavelength will be limited at different operating wavelengths. Hence, the minimum and maximum mode-spacing in the proposed EDF laser scheme are 0.75 and 15.35 nm in C-band range. Besides, the output performances of proposed fiber laser have also been studied and analyzed.

Stable Multiwavelength Semiconductor Laser Using FWM and SBS-Assisted Filter

A stable and flattened quadruple-wavelength laser system is proposed and experimentally investigated. The laser consists of an external injection Fabry-Pérot laser diode (FP-LD) and a stimulated-Brillouin-scattering (SBS)-assisted filter. In the measurement, the power difference (ΔP) of the lasing quadruple-wavelength can be enhanced within 2.0 dB by SBS-assisted filtering after 22-km single-mode fiber (SMF) propagation. In addition, we can change the two injected wavelengths for tuning the quadruple-wavelength. Besides, the output stability of the proposed laser has been studied and analyzed.

Erbium-doped fiber triple-ring laser configuration with single-longitudinal-mode dual-wavelength output

In this investigation, we propose and demonstrate a stabilized single-longitudinal-mode (SLM) dual-wavelength erbium-doped fiber (EDF) laser triple-ring cavity. Here, two fiber Bragg gratings (FBGs) are used inside the fiber cavity to generate dual-wavelength output. In order to complete the SLM output, the triple-ring configuration is utilized for suppressing the densely multi-longitudinal mode (MLM). The output powers and wavelengths of −8.4 and −8.5 dBm and 1535.76 and 1543.28 nm are obtained in the proposed dual-wavelength EDF laser, respectively. Moreover, the stability performances of output power and wavelength in the proposed EDF laser are also discussed.

Ultra-broadband amplified spontaneous emission source by using heterogeneous optical amplifier

In this work, we propose and experimentally investigate an ultra-broadband amplified spontaneous emission (ASE) light source with 113.8 nm bandwidth (1446.2 to 1560.0 nm) by using a cascaded two-stage optical amplifier, which is consisted of semiconductor optical amplifier (SOA, 1st stage) and erbiumdoped fiber amplifier (EDFA, 2nd stage), when the output intensity is above −35 dBm/0.01 nm. And, the EDFA only uses a 3 m long erbium-doped fiber (EDF) with a 27 mW pumping power and SOA is driven at 200 mA bias current. Moreover, the proposed amplifier also can provide a broadband gain amplification of 114 nm in the wavelengths of 1464.0 and 1578.0 nm with the noise figure distribution of 6.8 to 8.1 dB.

Stable Single-Longitudinal-Mode Erbium Fiber Ring Laser Utilizing Self-Injection and Saturable Absorber

In this work, we demonstrate a wavelength-tunable erbium-doped fiber (EDF) ring laser with stable single-longitudinal-mode (SLM) output. Here using the self-injection method and unpumped EDF-based saturable absorber can suppress other densely side-mode to achieve SLM. Hence, the output power and optical signal-to-noise ratio of proposed EDF ring laser are between −7.1 and 2.1 dBm and 30.1 and 36.5 dB in the tuning range of 1525.0 to 1574.0 nm, respectively. According to the proposed EDF laser structure, the wavelength operation range can extend to shorter L-band from C-band. Moreover, the output stability of the proposed EDF ring laser is also executed experimentally.