Wande Fan

Experimental study on vibration frequency response of micro-bend optic-fiber sensor

We make an experimental study on vibration frequency response of micro-bend optic-fiber sensor, and single-mode fibers and multi-mode fibers are used as the sensitive optic-fibers. Contrast between the two sensitive fibers is presented. Result shows that the micro-bend optic-fiber sensor has good frequency response characteristics and strong ability to restore the waveform. With the frequency varying in the range of 500-4762 Hz, the vibration sensors using multi-mode optic-fiber as the sensitive fiber is more sensitive than that using single-mode optic-fiber. And the former has better frequency response characteristics and stronger capacity of waveform revivification. But with the frequency in the range of 287-500 Hz, the latter is better.

High power cladding-pumped fiber lasers and their applications

In this paper, we review the recent works on high power cladding-pumped fiber lasers and amplifiers. And we will present some recent results on their applications such as Raman fiber laser and supercontinuum generation.

Broadly tunable ytterbium-doped photonic crystal fibre laser and high power superfluorescent fibre source

A 2.5W superfluorescent fiber source (SFS) and a tunable PCF laser with 74.4 nm tuning range and 5.5 W output power are experimentally demonstrated by utilizing an ytterbium-doped photonic crystal fiber (PCF) as the gain medium. The tunable operation of the laser is realized by rotating a diffraction grating. Effects of the degrees of the cleaved angle at the anti-reflection fiber end on the output characteristics of the laser and the SFS are investigated. A large cleaved angle is beneficial to realize a broad laser tuning range and beneficial to obtain a high power superfluorescent fiber source without parasitic lasing.

High-power broadband superfluorescent source with a Yb-doped double-cladding fiber

A high-power and broadband super-fluorescent source (SFS) based on an Yb-doped double-cladding fiber is described. The source is pumped at 976 nm from a laser diode by end-pumping system. The SFS generated a maximum 100 mW of broadband emission centered at 1066nm, with an about 40nm FWHM spectrum. The basic characteristics of the superfluorescent source, such as the output power and output linewidth, have been analyzed and studied.

Exceeded 1W average power, 1kW peak power, and all-fiber nanosecond Yb-doped amplifier

We report on the fiber-based amplification of a commercially packaged, fiber-pigtailed-pulsed diode laser operating at wavelength of 1064nm (bandwidth 0.45nm). The cascaded Yb-doped fiber amplifier can operate safely by using cascaded Wavelength division multiplexing (WDM) in each single-mode amplification stage. The total isolation of cascaded WDM can protect the laser diodes from destroyed by feedback of optical power. At repetition rate of 50kHz, pulse duration of 20ns, and average power of 0.5mW, output power up to 1.05W And peak power up to 1.05kW are obtained, with a high signal to noise ratio of 20dB. The whole system is a good choice for a preamplifier of high-power short-pulse amplification. The aim of the experiment is to study the design of preamplifier for high-power short-pulse amplifier via cascaded fiber-based amplifier.

Moiré fiber Bragg grating based on Yb3+-doped double-clad fiber

A novel Moire grating in Yb3+-doped double-clad fiber is reported. It consists of two intracore Bragg reflection gratings separated by an optical phase shift; the grating was formed through double exposure phase-mask method. An Yb3+-doped double-clad fiber laser based on this grating is presented. The laser wavelengths are 1055nm and 1057nm, respectively, with less than 0.1nm line-width, over 40dB signal-to-noise ratio.

Efficient tunable multiwavelength Yb3+-doped double-clad fiber laser

We present a tunable multi-wavelength Yb3+-doped double-clad fiber laser based on a Fabry-Perot filter (FPF). By adjusting the FPF, the number of lasing wavelength and their spaces are controlled which is in agreement well with the numerical analysis. The laser can oscillate at different number of wavelengths from one to ten while the oscillation is quite stable. In ten-wavelength laser, the system allows us to extract more than 1.5 W with a slope efficiency of 67%.

Analysis of the guided modes in triangular photonic crystal fibers using a full-vectorial numerical method

Properties of the photonic bandgaps effect and guided modes in triangular photonic crystal fibers have been studied by means of a full-vectorial plane-wave expansion method. Photonic crystal fibers under consideration consist of a triangular array of microscopic holes forming a two-dimensional photonic crystal cladding and a defect as their core. The photonic band-structure for photonic crystal cladding structures and the field intensity distribution of defect mode with various air-filling fractions and defect size are calculated. Guidance mechanisms in photonic crystal fibers with different configuration are also investigated.

Synchronously pumped mode-locked Yb3+-doped fiber laser

A synchronously pumped mode-locked Yetterbium-doped Fiber Laser which has the advantages of simple design and broad applications is obtained when the pump semiconductor laser current is modulated sinusoidally at the appropriate frequency. Steady pulses were obtained on harmonic mode-locked status. At the repetition rate of 623kHz,the pulse width is about 50ns,the average output power is 2.34 mW.

Radiation and reception of ultrashort electromagnetic pulses

We present the ultrashort electromagnetic pulses radiation system. The radiation antenna device are both illuminated by picosecond optical pulses, and the other same device for reception. Fabricated on a GaAs substrate, the antenna device consists of double-shottky-band and quasi-exponential antenna. We have obtained broad-band electromagnetic pulse radiation.