S-band erbium-doped silica fibre amplifier with flattened-gain ofover 21 dB

A gain-flattened erbium-doped silica fibre amplifier (EDSFA) has been developed for amplifying WDM signals in the S-band. The EDSFA exhibits a signal gain of over 21 dB, a gain excursion of less than 1.9 dB, and a noise figure of less than 6.7 dB in the 1491-1518 nm wavelength range     

High gain limiting erbium-doped fibre amplifier with over 30 dB dynamic range

A limiting optical amplifier is demonstrated using three cascaded stages of erbium-doped fibre amplifiers. A constant output power of +12.9 dBm was obtained for an input power ranging from -30 to 1.5 dBm. The optical noise figure of the amplifier has been measured over the >30 dB dynamic range. Design guidelines for optical limiting amplifiers are also presented.<>     

Repeaterless transmission with 62.9 dB power budget using a highly efficient erbium-doped fibre amplifier module

A 565 Mbit/s DPSK heterodyne transmission experiment has been demonstrated using a fibre post-amplifier. Over +12 dBm output powers were obtained in a both end pumping configuration for 35 mW total launched pump power, leading to a repeaterless link budget of 62.9 dB.<>     

Efficient pump wavelengths of erbium-doped fibre optical amplifier

By choosing pump wavelengths at which excited state absorption does not occur, efficient high gain operation of erbium-doped fibre amplifiers is possible. Practical pump wavelengths of 532 nm and 980 nm are identified as optimal, giving gains as high as 1.35 dB/mW and 2.2 dB/mW of pump at the two wavelengths, respectively.<>     

High-gain broad spectral bandwidth erbium-doped fibre amplifier pumped near 1.5 mu m

A small-signal gain exceeding 25 dB, and a 3 dB spectral bandwidth of 35 nm around 1.545 mu m are obtained for an erbium-doped silica fibre amplifier pumped in the short wavelength wing of the 1.5 mu m absorption band.<>     

Bidirectional erbium-doped fibre amplifier with non-reciprocaloptical filter

A 24 dB gain bidirectional erbium-doped fibre amplifier (EDFA) using a new non-reciprocal optical filter is demonstrated. Using the amplifier 2.5 Gbit/s×8 channel WDM signals were transmitted over 160 km long singlemode fibre. The measured penalty caused by multiple optical reflection was negligible     

Wavelength-locked, two-stage fibre Fabry-Perot filter for dense wavelength division demultiplexing in erbium-doped fibre amplifier spectrum

Insertion loss of 5.6 dB and finesse greater than 2000 within a 40 nm tuning range are demonstrated in a wavelength-locked, two-stage fibre Fabry-Perot filter capable of separating 1000 channels in an erbium-doped fibre amplifier spectrum.<>     

W波段增益为25.7 dB两级cascode放大器

AW-bandtwo-stageamplifierMMIChasbeendevelopedusingafullypassivated 2 × 20 μm gate-width and 0.15 μm gate-length InP-based high electron mobility transistor （HEMT） technology. The two-stage amplifier has been realized in combination with a coplanar waveguide technique and cascode topology, thus leading to a compact chip-size of 1.85 × 0.932 mm^2 and an excellent small-signal gain of 25.7 dB at 106 GHz. Additionally, an inter-digital coupling capacitor blocks low-frequency signal, thereby enhancing the stability of the amplifier. The successful design of the two-stage amplifier MMIC indicates that InP HEMT technology has a great potential for W-band applications.     

Characteristics of regenerative erbium-doped fibre ring amplifier

A study is presented into the dynamic characteristics of a unidirectional regenerative erbium-doped fibre ring amplifier at below laser threshold. A considerable improvement in gain and noise figure performance was observed due to the suppression of amplified spontaneous emission in the regenerative amplification process. It was found that lower feedback power provides higher optical gain. An optical signal of -33.5 dB was found to experience a gain of ⩾35 dB at and near the resonance wavelength using 1% feedback by an optical fibre coupler for an optical pump (1480 nm) power as low as 10 mW     

Twincore erbium-doped fibre amplifier with passive spectral gain equalisation

Automatic spectral gain equalisation is demonstrated using controlled spatial hole-burning in an erbium-doped twincore fibre. Gain equalisation rates up to 0.11 dB difference between input signal levels are demonstrated and should increase the useful bandwidth of cascaded amplifiers.<>     

L-band erbium-doped fibre amplifier with clamped- and flattened-gain using FBG

A gain clamped long wavelength band erbium-doped fibre amplifier (L-band EDFA) based on a ring laser cavity is demonstrated using a fibre Bragg grating (FBG) at the output end of the amplifier. This new design provides a good gain clamping as well as a gain flattening. The gain is clamped at 16.9 dB with gain variation of less than 0.1 dB from input signal power of -40 to -18 dBm by setting the VOA=5 dB. Also, the amplifier has the flattest gain spectrum at VOA=5. The gain variation is less than 1.0 dB within the wavelength range from 1570 to 1600 nm. This gain clamped amplifier also can support a 12 channel WDM system.     

Low threshold optical differential amplification using a fibre amplifier in a nonlinear ring resonator

The basis for low threshold differential amplification in a nonlinear fibre resonator by incorporating an in-line fibre amplifier in the cavity is reported.<>     

两段级联宽带碲基掺铒光纤放大器特性研究

利用四能级结构速率方程组和光功率传输方程组,研究了在碲基掺铒光纤(EDTF)中内插一个光隔离器、形成两段级联的碲基掺铒光纤放大器(EDTFA)后对EDTFA性能的改善.结果表明,在给定泵浦方式、泵浦功率、纤芯掺杂浓度和输入信号功率条件下,两段级联EDTFA可以有效的抑制光纤中反向传输放大自发辐射(ASE)噪声,降低反转粒子数的消耗,从而提高信号增益、输出功率,并且降低了噪声系数.对不同光纤长度和光隔离器内插在光纤中不同位置的研究表明,当光纤为最佳长度和光隔离器在最佳位置处时,可使短波长信号增益增加10 dB,噪声系数减小1 dB,并进一步增加了放大带宽以及功率转换效率.     

High-sensitivity low coherence reflectometer using erbium-doped superfluorescent fibre source and erbium-doped power amplifier

A broadband light source with an output of 150 mW at 1536 nm is constructed by using an erbium-doped power amplifier coupled to an erbium-doped superfluorescent fibre source. A nearly shot-noise-limited sensitivity of -161 dB and a dynamic range of 54 dB are achieved with an optical low coherence reflector using this source.<>     

9 dB gain improvement of 1300 nm optical amplifier by amplified spontaneous emission suppressing fibre design

A new design of a Nd-doped fluoride fibre for 1300 nm small-signal amplification is presented. By placing the active material so that the 1050 nm amplified spontaneous emission is discriminated, a gain improvement of up to 6.6 dB is predicted. By including higher order pump modes an extra 2.1 dB gain improvement is achieved.<>     

Temperature dependent gain and noise characteristics of a 1480 nm-pumped erbium-doped fibre amplifier

The gain of a 1480 nm pumped erbium-doped fibre amplifier has been measured over the temperature range -40 degrees C to 60 degrees C. The characteristics can be modelled using emission and absorption cross-section data determined for this temperature range. The temperature dependence of the gain spectrum and noise figure are also predicted.<>     

Evanescent amplification in a single-mode optical fibre

By replacing a portion of the cladding of a single-mode fibre with a laser dye, amplification can be achieved by means of an evanescent field interaction. External gains as high as 22 dB have been measured by guiding both a pulsed pump and CW signal within the single-mode fibre.     

Coherent lightwave amplification and stimulated Brillouinscattering in an erbium-doped fiber amplifier

The stimulated Brillouin scattering (SBS) of coherent light pulses launched into an erbium-doped fiber (EDF) is reported. In a 50 m EDF, the SBS peak power reaches about 40 dBm for input powers higher than the threshold power of about 6 dBm. SBS and its amplification in an erbium-doped fiber amplifier (EDFA) result in the deformation of a forward-amplified pulse due to the Brillouin power conversion and deterioration of the EDFA population inversion. It is also shown that very short EDF is effective in suppressing the SBS     

0.1-15 GHz AM and FM response of erbium-doped fibre amplifier

The AM and FM response of an erbium-doped fibre amplifier has been characterised for signal modulation frequencies in the range 130 MHz to 15 GHz. Both the amplifier gain and phase are found to be constant for both amplitude-modulated and frequency-modulated signals.<>