We report an approach to the control of longitudinal mode structure in erbium-doped fiber lasers that uses saturable absorbers and spatial hole-burning effect laser cavity. Two- three-mode are successfully demonstrated, output properties compared with theoretical calculations.

A stable single-frequency fiber ring laser is proposed that operates in a single mode for more than an hour by incorporating unpumped erbium-doped (EDF) as saturable absorber filter and optimizing the length of EDF used gain medium. This can be continuously tuned to 25-GHz spacing precisely matches ITU-T grids temperature control etalon filter. had signal-to-source spontaneous emission ratio higher 70 dB, lasing frequencies 361 channels was matched with excellent flatness. Frequency offset...

We demonstrate a thulium-doped fiber ring laser (TDFRL) integrated with an amplifier, which has watt-level single-frequency output at 2 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu\text{m}$</tex-math></inline-formula> 120-nm wavelength tunability. The TDFRL is constructed based on hybrid ring-linear resonator configuration. An unpumped TDF incorporated as self-constructed saturable absorption...

We describe the experimental construction of a single-longitudinal-mode erbium-doped fiber ring laser equipped with resonator filter. The system is designed to avoid mode hopping and can be frequency scanned for spectroscopic sensor applications. modified conventional filter have capability reduce transmittance unwanted modes, which essential scanning without hopping.

A 1530-nm band has been studied as a pump wavelength for the long-wavelength-band erbium-doped fiber amplifier (L-band EDFA). The source is built using tunable light and cascaded conventional-band (C-band) EDFA. L-band EDFA uses forward pumping scheme. Within band, 1545-nm demonstrates 0.45-dB/mW gain coefficient, which twice better than that of conventional 1480-nm pumped noise figure at worst 6.36 dB, 0.75 dB higher Such high-gain coefficient indicates consumes low power.

We study threshold features of a Brillouin-shifted Stokes comb generated in distributed fiber Raman amplifier. When the input power Brillouin pump is linearly increased high gain, first wave grows exponentially at much lower and then experiences an appreciable decrease vicinity comb's threshold. This reduction Stokes, which we did not see mentioned previous reports, was caused by transfer to higher-order lines initiated generation. Moreover, effects pumping direction on are investigated.

We report development of a frequency-stabilized mid-infrared continuous-wave (cw) optical parametric oscillator (OPO) based on fan-out grating MgO:PPLN crystal pumped at 1064 nm. The OPO resonator was designed as pump-enhanced standing-wave cavity that resonates to the pump and signal beams. To realize stable operation OPO, we applied modified Pound-Drever-Hall technique, which is well-known method for powerful laser frequency stabilization. Tuning poling period allows wavelength-tunable...

We report a continuous-wave (CW) optical parametric oscillator (OPO) based on MgO-doped periodically poled LiNbO(3) (MgO:PPLN) crystal. The 532 nm pump generates coherent radiation that is tunable from 800 to 920 for the signal and 1250 1580 idler, respectively. OPO output power exhibits slowly varying instability we attribute thermal effect induced by pump. This truncated means of low-pass servo includes single-mode fiber filters beam into single spatial mode. resulting characteristics are...

We demonstrate a measurement apparatus to inspect spatial uniformity of quantum efficiency solar cells using beam projector. Deviation irradiance from the used projector over area 1.5×0.8 m on cell plane was flattened within ±2.6% through gray scale adjustment, which originally about 200%. Scanning small square image with an 3×3 mm square-shaped photovoltaic 15.6×15.6 cm, we could identify locations according level and showed that had deviation more than 10%. Utilizing advantageous feature...

We propose and demonstrate a method for measuring nonlinear transmission (NLT) of holmium-doped fiber (HDF) as saturable absorber (SA) by using two calibrated photodiodes. The HDF with length 10 cm is under test reference, the NLT measurement carried out from 1930 to 1970 nm tunable continuous-wave (CW) thulium-doped laser (TDFL). result finds that modulation depth 56% at 1950 decreases down 37% both nm. Saturation power about 20 mW all measured wavelengths. validity SA passively Q-switched...

A simple method of Rayleigh scattering noise calculation in fibre Raman amplifiers is proposed. Using the method, it disclosed that optimal pump power lower when both signal and amplified spontaneous emission (ASE) are considered than ASE only considered.

Abstract The maximum peak power of ultrafast mode-locked lasers has been limited by cubic nonlinearity, which collapses the pulses and consequently leads to noisy operation or satellite pulses. In this paper, we propose a concept achieve with high beyond limitation nonlinearity help dissipative resonance between quintic nonlinear phase shifts anomalous group velocity dispersion. We first conducted numerical study investigate existence solitons in fiber cavity dispersion (U-DSAD) found four...

Transient effects in low-noise dispersion-compensating hybrid fiber amplifier (DC-HFA) are presented to show the combined dynamics of erbium-doped and Raman amplifier. features surviving signal channel analyzed with numerical simulation each stage DC-HFA. A gain-control method that utilizes transit time is suggested it has advantages enough for electronics lower noise figure channels.

Fabrication method of a fiber optic electric field sensing probe using polarization maintaining (PMF) is described including birefringent axes aligning system. The basically fiber-coupled Fabry-Perot resonator where thin wafer LiTaO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> with an external cavity mounted onto the end PMF. An optical wave from superluminescent laser diode after linear polarizer parallel to slow axis PMF made enter...

We present a tunable single longitudinal mode Tm-doped fiber ring laser incorporating self-constructed saturable absorption grating and blazed with wavelength tunability of over 100 nm. The spectral temporal characteristics the output are described.

We propose an approach to elevate the signal-to-noise ratio (SNR) in a microwave electric field sensor system with polarization maintaining fiber (PMF) probe incorporated electro-optic (EO) crystal. The optimal parameters were determined obtain best SNR based on suggested approach, which was validated experimentally. Using newly fabricated PMF close design, improvement of 2.5 dB compared our previous successfully demonstrated measurements.

We calculate optical properties of guided modes a hybrid-guiding photonic crystal fiber. The design and modeling such PCF is made by replacing air holes with inserts high refractive index material layer in order. as mode intensity profile, dispersion, birefringence, confinement loss, chromatic dispersion during transition the guiding mechanism are analyzed discussed. region also compared those reference index-guiding bandgap-guiding fibers.

Intrinsic Fabry-Perot optical fiber sensors were embedded to the tensile side of 20 cm by 150 cement concrete structures. The attached reinforcing steels and then, concretes applied. It took 30 days for curing specimens. After that, specimens tested with 4-point bending method a universal testing machine. Strains measured recorded strain gauges near sensors. Output data sensor showed good linearity from up 2000 microstrain. response after yielding structure while metal film did not show any...

Backward pumped C- and L-band distributed fiber Raman amplifiers are described, where discrete losses from 0-8 dB were added at various positions to examine the effect of localized loss. Below 3-dB additional loss, overall optical performance degraded similarly, regardless loss position in a hybrid erbium-doped amplifier. Above 3 dB, degradation worsened as became closer signal output. The spectral shape change output against variation was made tolerable within ±0.4 simply by balancing power...

KRISS, NMISA, CMS/ITRI, NMC-A*STAR, NMIJ/AIST, NMIA, NML-SIRIM, NIM, and VNIIOFI conducted a supplementary comparison on the fiber optic power responsivity at 1310 nm 1550 nm. The aim of this was to examine equivalence among participating laboratories provide supporting evidence for associated CMC claims in BIPM KCDB. Finally, realized or preserved luminous flux values all other participants were compared with EURAMET-RV star-type pilot batches three six lamps various types. DOEs respect...

We report on experimental realization of optical injection locking a singly resonant continuous-wave parametric oscillator (OPO) based thermally induced waveguide in magnesium-oxide doped periodically poled lithium niobate. An external cavity diode laser is used to control the frequency signal output OPO at 795 nm. The key successful was improvement spatial modes by special operating condition with waveguide. phase coherence confirmed recording high-contrast interference fringe between and...