Fabrication and emission properties of Er3+/Yb3+ codoped tellurite glass fiber for broadband optical amplification

Tellurite glass is proposed as a host for broadband erbium-doped fiber amplifiers because of their excellent optical and chemical properties. A new single mode Er3+/Yb3+ codoped tellurite fiber with D-shape cladding geometry is fabricated in this work. When pumped at 980 nm, a broad erbium amplified spontaneous emission (ASE) nearly 100 nm in the wavelength range of 1450-1650 ran around 1.53 mu m is observed. It was found that the emission spectrum from erbium in tellurite glass fibers is almost twice as broad as the corresponding spectrum in tellurite bulk glass. The changes in ASE with regard to fiber lengths and pumping power were measured and discussed. The output of about 2.3 mW from Er3+/Yb3+ codoped tellurite fiber ASE source is obtained under the pump power of 700 mW. The broad 1.53 mu m emission of Er3+ in Er3+/Yb3+ codoped tellurite glass fiber can be used as host material for potential broadband optical amplifier and tunable fiber lasers. (c) 2005 Elsevier B.V. All rights reserved.

Enhanced broadband near-infrared luminescence and optical amplification in Yb-Bi codoped phosphate glasses

Yb-Bi codoped phosphate glass was prepared and its properties were compared with Bi-doped phosphate glass. The broadband infrared luminescence intensity from Yb-Bi codoped glass was similar to 32 times stronger than that of Bi-doped glass. The single-pass optical amplification was measured on a traditional two-wave mixing configuration. No optical amplification was observed in Bi-doped glass, while apparent broadband optical amplification between 1272 and 1336 nm was observed from Yb-Bi codoped glass with 980 nm laser diode excitation. The highest gain coefficient at 1272 nm of Yb-Bi codoped glass reached to 2.62 cm(-1). Yb-Bi codoped phosphate glass is a promising material for broadband optical amplification. (C) 2008 American Institute of Physics.

Inhomogeneous broadening, luminescence origin and optical amplification in bismuth-doped glass

Absorption and luminescence spectra and optical amplification in bismuth-doped germanate silicate glass were investigated. Two kinds of bismuth ion valence states could exist in the glass. One is Bi2+, which has shown red luminescence, another might be Bi+, which is the active center for infrared luminescence. The infrared luminescence excited at 700, 800, and 980 nm should be ascribed to the electronic transition P-3(1) --> P-3(0) of Bi+ ions in three distinct sites. The shifting, broadening, and multiple configuration of the luminescence could be due to the randomly disorder of local environment and multiple sites of the active centers. In this glass, obvious optical amplification was realized at 1300 nm wavelength when excited at 808 and 980 nm, respectively.

Novel Bi-doped glasses for broadband optical amplification

Broadband infrared luminescence is observed in various Bi-doped oxide glasses prepared by conventional melting-quenching technique. The absorption spectrum of the Bi-doped germanium oxide glass consists of five broad peaks at below 370, 500, 700, 800 and 1000 nm. The fluorescence spectrum exhibits a broad peak at about 1300 nm with full width at half maximum (FWHM) of more than 300 nm when excited by an 808 nm laser diode. The fluorescence lifetime at room temperature decreases with increasing Bi2O3 concentration. Influence of the glass composition and melting atmosphere on the fluorescence lifetime and luminescent intensity is investigated. The mechanism of the broadband infrared luminescence is suggested. The product of stimulated emission cross-section and lifetime of the Bi-doped aluminophosphate glass is about 5.0 X 10(-24) cm(2) s. The glasses might be promising for applications in broadband optical fiber amplifiers and tunable lasers. (c) 2007 Elsevier B.V. All rights reserved.

Investigations on bismuth and aluminum co-doped germanium oxide glasses for ultra-broadband optical amplification

The broadband luminescence covering 1.2-1.6 mu m was observed from bismuth and aluminum co-doped germanium oxide glasses pumped by 808 nm laser at room temperature. The spectroscopic properties of GeO2:Bi,Al glasses strongly depend on the glass compositions and the pumping sources. To a certain extent, the Al3+ ions play as dispersing reagent for the infrared-emission centers in the GeO2:Bi,Al glasses. The broad infrared luminescence with a full width at half maximum larger than 200 nm and a lifetime longer than 200 mu s possesses these glasses with the potential applications in broadly tunable laser sources and ultra-broadband fiber amplifiers in optical communication field. (c) 2005 Elsevier B.V. All rights reserved.

Harmonic Millimeter Wave Generation and Frequency Up-Conversion Using Optical Injection Locking and Brillouin Selective Sideband Amplification

Harmonic millimeter wave (mm-wave) generation and frequency up-conversion are experimentally demonstrated using optical injection locking and Brillouin selective sideband amplification (BSSA) induced by stimulated Brillouin scattering in a 10-km single-mode fiber. By using this method, we successfully generate third-harmonic mm-wave at 27 GHz (f(LO) - 9 GHz) with single sideband (SSB) modulation and up-convert the 2GHz intermediate frequency signal into the mm-wave band with single mode modulation of the SSB modes. In addition, the mm-wave carrier obtains more than 23 dB power gain due to the BSSA. The transmission experiments show that the generated mm-wave and up-converted signals indicate strong immunity against the chromatic dispersion of the fibers.

Parametric Analysis for Monitoring 2D Kinetics of Receptor-Ligand binding

Thermal fluctuation approach is widely used to monitor association kinetics of surface-bound receptor-ligand interactions. Various protocols such as sliding standard deviation (SD) analysis (SSA) and Page's test analysis (PTA) have been used to estimate two-dimensional (2D) kinetic rates from the time course of displacement of molecular carrier. In the current work, we compared the estimations from both SSA and modified PTA using measured data from an optical trap assay and simulated data from a random number generator. Our results indicated that both SSA and PTA were reliable in estimating 2D kinetic rates. Parametric analysis also demonstrated that such the estimations were sensitive to parameters such as sampling rate, sliding window size, and threshold. These results furthered the understandings in quantifying the biophysics of receptor-ligand interactions.

Optical gain at 1550 nm from colloidal solution of Er3+-Yb3+ codoped NaYF4 nanocubes

We demonstrated optical amplification at 1550 nm with a carbon tetrachloride solution of Er3+-Yb3+ codoped NaYF4 nanocubes synthesized with solvo-thermal route. Upon excitation with a 980 nm laser diode, the nanocube solution exhibited strong near-infrared emission by the I-4(13/2) -> I-4(15/2) transition of Er3+ ions due to energy transfer from Yb3+ ions. We obtained the highest optical gain coefficient at 1550 nm of 0.58 cm(-1) for the solution with the pumping power of 200 mW. This colloidal solution might be a promising candidate as a liquid medium for optical amplifier and laser at the optical communication wavelength. (C) 2009 Optical Society of America

Pulse compression by filamentation in argon with an acoustic optical programmable dispersive filter for predispersion compensation

We have experimentally demonstrated pulses 0.4 mJ in duration smaller than 12 fs; with an excellent spatial beam profile by self-guided propagation in argon. The original 52 fs pulses from the chirped pulsed amplification laser system are first precompressed to 32 fs by inserting an acoustic optical programmable dispersive filter instrument into the laser system for spectrum reshaping and dispersion compensation, and the pulse spectrum is subsequently broadened by filamentation in an argon cell. By using chirped mirrors for post-dispersion compensation, the pulses are successfully compressed to smaller than 12 fs.

Optical properties of transparent alkali gallium silicate glass-ceramics containing Ni2+-doped beta-Ga2O3 nanocrystals

Broadband near-infrared (IR) luminescence in transparent alkali gallium silicate glass-ceramics containing N2+-doped beta-Ga2O3 nanocrystals was observed. This broadband emission could be attributed to the T-3(2g) (F-3) -> (3)A(2g) (F-3) transition of octahedral Ni2+ ions in glass-ceramics. The full width at half-maximum (FWHM) of the near-IR luminescence and fluorescent lifetime of the glass-ceramic doped with 0.10 mol% NiO were 260 nm and similar to 1220 mu s, respectively. It is expected that transparent Ni2+-doped beta-Ga2O3 glass-ceramics with this broad near-IR emission and long fluorescent lifetime have potential applications as super-broadband optical amplification media.

CW-pumped evanescent amplification based on side-polished fiber with heavily Er3+-doped glass overlay

A novel diffractive-pumping scheme is proposed to improve the evanescent amplification using blazed fiber grating for the first time. We also investigate the cw-pumped-evanescent amplification at 1.55 mu m wavelength with the relative optical gain pumped at 1480 nm of around 2 dB based on side-polished fiber with the effective interaction length as long as 16 mm and with a heavily Er3+-doped (N-Er(3+) > 1.19 x 10(21) ions/cm(3)), low refractive index (n(1550) < 1.47) glass overlay, which has no concentration quenching (tau(f) = 9.0 ms).

Spectroscopic properties of Er3+ doped TeO2-BaO (Li2O, Na2O)-La2O3 glasses for 1.5-mu m optical amplifiers

This paper reports on the optical spectroscopic properties and thermal stability of Er3+-doped TeO2-BaO (Li2O,NaO)-La2O3 glasses for developing 1.5-mu m fiber amplifiers. Upon excitation at 977 nm laser diode, an intense 1.53-mu m infrared fluorescence has been observed with a broad full width at half maximum (FWHM) of about 60 nm for the Er3+-doped TeO2-BaO (Li2O, Na2O)-La2O3 glass with 10 mol% of BaO. The calculated fluorescence lifetime and the emission cross-sections of the 1.53-mu m transition are 2.91 ms and similar to 9.97 x 10(-21) cm(2), respectively. It is noted that the gain bandwidth, a, x FWHM, of the TeO2-BaO-La2O3Er2O3 glass is about 600, which is significantly higher than that in silicate and phosphate glasses. Meanwhile, it is interesting to note that the TeO2-BaO-La2O3-Er2O3 glass has shown a high glass thermal stability and good infrared transmittance. As a result, TeO2-BaO (Li2O, Na2O)-La2O3 glass with 10 mol% of BaO has been considered to be more useful as a host for broadband optical fiber amplifier. (c) 2005 Elsevier B.V. All rights reserved.

NUMERICAL ANALYSIS OF A NOVEL 980nm MICROCAVITY SEMICONDUCTOR OPTICAL AMPLIFIER WITH HIGH GAIN AND LOW NOISE

A novel microcavity semiconductor optical amplifier ( MCSOA) was proposed by incorporating top and bottom distributed Bragg reflectors ( DBRs) into the waveguide structure of conventional traveling-wave semiconductor optical amplifiers(TW-SOAs). The incoming( outgoing) light beam incidented onto (escaped from) the waveguide structure at a oblique angle through two optical windows, where the top DBR was etched away, and anti-reflection coating was deposited. The light beams inside the optical cavity were reflected repeatedly between two DBRs and propagated along waveguide in a zigzag optical path. The performance of the MCSOA was systematically investigated by extensive numerical simulation based on a traveling-wave model by taking into account the comprehensive effects of DBRs on both the amplification of signals and the filtering of spontaneous emission( SE). Our results show that the MCSOA is capable of achieving a fiber-to-fiber gain as high as 40dB and a low noise figure is less than 3.5dB.

A COMMON-CAVITY 2-SECTION INGAASP/INP BISTABLE LASER WITH A LOW OPTICAL SWITCHING POWER

The characteristics of the steady-state and the transient response to external light excitation of a common-cavity two-section (CCTS) bistable semiconductor laser is investigated. The results on the relation of light output versus light input, the wavelength match, optical amplification and optical switching are presented. Experimental results are compared to the results of a computer simulation.