Er3+/Yb3+共掺双包层光纤放大器实验研究

对1550nm高功率窄线宽光纤放大器进行了实验研究。该放大器采用双级放大(MOPA)结构, 其中第一级预放采用5 m长的掺Er3+光纤, 将种子光信号放大到约90 mW; 采用15 m长的Er3+/Yb3+共掺双包层光纤放大器作为二级放大, 抽运源采用2支工作波长为980 nm的大功率激光二极管(LD), 抽运阈值功率约1.3 W。 当抽运功率为10.8 W时, 得到放大激光输出功率为1.97 W, 光-光转换效率为18 %, 斜率效率为21%, 增益大于13 dB。所采用的种子光源为1550 nm单频窄线宽(DFB)LD, 输出功率为10 mW; 采用延迟自外差方法对种子源及放大器输出的线宽进行测量, 测量结果显示该种子源及放大后的激光输出的3 dB线宽均约为220 kHz, 在目前的实验条件下, 没有观察到放大后的激光线宽展宽现象。     

A comparative study of an erbium doped fiber amplifier pumped at811 and 980 nm

The gain and saturation characteristics of an erbium doped fiber amplifier pumped in both the 800 nm and 980 nm pump bands are presented. The maximum gain coefficients are found to occur at the same fiber lengths for both 811 nm and 980 nm pumping. They are 1.2 dB/mW and 7.8 dB/mW, respectively. The amplifier thresholds at both pump wavelengths are quantitatively compared using a simple model and measured attenuation coefficients. Signal amplification at 1533 nm is found to suffer more from the effects of excited state absorption than signal amplification at 1553 nm     

Design considerations for an integrated 1.8GHz parametric amplifier

A hybrid-integrated parametric amplifier has been fabricated in a microstrip transmission-line configuration. General design considerations and their implementation in a microstrip medium are discussed. The amplifier exhibited a power gain of 10 dB and 50-MHz half-power bandwidth with a noise figure of 2.0 dB. It was pumped atX-band frequency and required only 10 mW of pump power. The integrated pump source consisted of the transistor oscillator and a varactor quadrupler stage.     

8-mV threshold Er/sup 3+/-doped planar waveguide amplifier

We report on the gain characteristics of a low threshold (8 mW) Er/sup 3+/-doped planar optical waveguide amplifier. Net fiber to fiber gain of 4.5 dB is achieved at a signal wavelength of 1536 nm with 80 mW of 980-nm pump power. This device represents significant progress toward a planar amplifier module pumped by a single laser diode.     

分布式光纤喇曼放大器实验研究

为了对后向抽运分布式宽带光纤喇曼放大器的特性进行实验研究,采用多波长1426nm,1440nm,1460nm,1475nm和1495nm的半导体激光器作为抽运源,实现了C+L波段近80nm带宽的信号光放大,获得了比较好的平坦增益、偏振相关增益,系统平均开关增益为10.7dB,增益平坦度为1.5dB,最大噪声指数为-1.96dB,偏振相关增益小于0.4dB。结果表明,光纤喇曼放大器的抽运源波长、功率选择比较合理,系统所有技术指标均满足光纤通信使用要求。这一结果将对通信产业化发展有着重要的指导作用。     

Diode-laser pumped erbium-doped fluorozirconate fibre amplifier for the 1530 nm communications window

An erbium-doped fluorozirconate fibre amplifier has been pumped at 1480 nm using a semiconductor diode laser. The small signal gain was 15 dB for 25 mW launched pump power. The ASE bandwidth was 45 nm and the predicted noise figure was 5 dB.<>     

Design Considerations for an Integrated 1.8-GHz Parametric Amplifier

A hybrid-integrated parametric amplifier has been fabricated in a microstrip transmission-line configuration. General design considerations and their implementation in a microstrip medium are discussed. The amplifier exhibited a power gain of 10 dB and 50-MHz half-power bandwidth with a noise figure of 2.0 dB. It was pumped at X-band frequency and required only 10 mW of pump power. The integrated pump source consisted of the transistor oscillator and a varactor quadrupler stage.     

Low-noise intelligent cladding-pumped L-band EDFA

We present results on a low-cost cladding-pumped L-band amplifier based on side pumping (GTWave) fiber technology and pumped by a single 980-nm multimode diode. We show that simultaneous noise reduction and transient suppression can be achieved by using gain clamping by a seed signal (/spl lambda/=1564 nm). In the gain-clamping regime, the amplifier exhibits 30-dB gain over 1570-1605-nm spectral band with noise figure below 7 dB. The noise figure can be further reduced to below 5 dB by utilizing a low power single-mode pump at 980 nm. The erbium-doped fiber amplifier is relatively insensitive to input signal variations with power excursions below 0.15 dB for a 10-dB channel add-drop.     

Performances of Erbium‐Doped Fiber Amplifier Using 1530nm‐Band Pump for Long Wavelength Multichannel Amplification

The performance of a long wavelength‐band erbium‐doped fiber amplifier (L‐band EDFA) using 1530nm‐band pumping has been studied. A 1530nm‐band pump source is built using a tunable light source and two C‐band EDFAs in cascaded configuration, which is able to deliver a maximum output power of 23dBm. Gain coefficient and noise figure (NF) of the L‐band EDFA are measured for pump wavelengths between 1530nm and 1560nm. The gain coefficient with a 1545nm pump is more than twice as large as with a 1480nm pump. It indicates that the L‐band EDFA consumes low power. The noise figure of 1530nm pump is 6.36dB at worst, which is 0.75dB higher than that of 1480nm pumped EDFA. The optimum pump wavelength range to obtain high gain and low NF in the 1530nm band appears to be between 1530nm and 1540nm. Gain spectra as a function of a pump wavelength have bandwidth of more than 10nm so that a broadband pump source can be used as 1530nm‐band pump. The L‐band EDFA is also tested for WDM signals. Flat Gain bandwidth is 32nm from 1571.5 to 1603.5nm within 1dB excursion at input signal of –10dBm/ch. These results demonstrate that 1530nm‐band pump can be used as a new efficient pump source for L‐band EDFAs.     

Design Considerations for an Integrated 1.8-GHz Parametric Amplifier

A hybrid-integrated parametric amplifier has been fabricated in a microstrip transmission-line configuration. General design considerations and their implementation in a microstrip medium are discussed. The amplifier exhibited a power gain of 10 dB and 50-MHz half-power bandwidth with a noise figure of 2.0 dB. It was pumped at X-band frequency and required only 10 mW of pump power.The integrated pump source consisted of the transistor oscillator and a varactor quadruple stage.     

Use of LD-pumped erbium-doped fiber preamplifiers with optimalnoise filtering in a FDMA-FSK 1 Gb/s star network

An erbium-doped fiber amplifier was implemented in a closely spaced FDMA-FSK (frequency-division-multiple-access-frequency-shift-keyed) optical star network with a signaling rate of 1 Gb/s per channel. The fiber preamplifier, which is laser-diode pumped, increases the sensitivity of the direct-detection avalanche photodiode (APD) receiver by 14 dB, allowing for an increased number of network users. This enhanced sensitivity nearly corresponds to all of the available gain of the amplifier. Furthermore, the amplifier noise is optimally filtered by means of a wide band interference filter cascaded with a narrow band fiber Fabry-Perot filter     

用于S波段光纤拉曼放大器增益平坦的长周期光纤光栅设计

根据实际所测得的S波段光纤拉曼放大器的信号增益谱,通过对长周期光纤光栅具体参数的选定,由两个长周期光纤光栅级联滤波的组合,可以使增益图谱在50 nm(1485-1535 nm)带宽内,增益平坦度达到±0.6dB以内.由三个长周期光纤光栅级联滤波组合,可以使增益图谱在49 nm(1490-1539 nm)带宽内,增益平坦度达到0.5 dB, 55 nm(1485-1540 nm)带宽内,增益平坦度达到1 dB.这对扩大长周期光纤光栅增益平坦滤波器的运用范围,扩大单泵浦S波段光纤拉曼放大器的有效增益带宽有着积极的意义.     

Diode pumped operation of thulium doped fluoride fibre amplifiersuitable for first window systems

A fully connectorised diode laser pumped first window amplifier has been constructed, for the first time, around a thulium doped fluoride fibre. For a 780/806 nm combination of pump and signal wavelengths, small signal gains of 25-26 dB and gain efficiencies of 2.4 dB/mW have been achieved. In addition, output powers approaching +13 dBm are possible for a launched pump power of 31 mW, which corresponds to a conversion efficiency of around 650%     

Er3+-doped fiber amplifier pumped by 0.98 μm laserdiodes

The performance of an Er³⁺-doped fiber amplifier pumped by 0.98 μm InGaAs laser diodes (LDs) is reported. By using a fiber with low Er³⁺ content and optimizing the fiber length, a maximum signal gain of 37.8 dB at 30-mW pump power was realized at a signal wavelength of 1.536 μm. A maximum gain coefficient of 1.9 dB/mW at 14 mW pump power was achieved. It was found that the fiber amplifier pumped by the 0.98-μm LDs is twice as efficient as that pumped by 1.48-μm LDs, from the viewpoint of both required fiber length and the attained gain     

Erbium-doped fiber amplifier with 54 dB gain and 3.1 dB noisefigures

It is shown that for practical pump powers (<100 mW) a combination of high gain (>33 dB) and low noise figure (3 dB) cannot simultaneously be achieved with a conventional codirectionally pumped EDFA. However, using a codirectionally pumped composite EDFA incorporating an isolator overcomes the problem, and an amplifier with 51 dB (54 dB) gain and 3.1 dB noise figure (NF) for only 45 mW (93 mW) of pump power is demonstrated     

Erbium-doped optical fiber amplifiers pumped in the 660- and 820-nmbands

State-of-the-art erbium (Er)-doped optical fiber amplifiers (EDFA's) pumped in the 660- and 820-nm bands are described. We have demonstrated highly efficient EDFA's incorporating optimized 664- and 827-nm pump wavelengths and an Er-doped high numerical aperture (NA) fiber with thermally diffused expanded core (TEC) fiber ends. Gain coefficients of 3.8 and 1.3 dB/mW at respective wavelengths of 664 and 827 nm were achieved at a signal wavelength of 1535 nm. Noise figures of 3.1 and 4.1 dB at respective pump wavelengths of 670 and 827 nm were obtained at a signal wavelength of 1535 nm. A highly efficient Er-doped fiber amplifier module, in which an AlGaInP visible laser diode (LD) was used as the pump source, was successfully developed as a practical application of this technology. A maximum overall gain coefficient of 3.0 dB/mW was achieved at a signal wavelength of 1535 nm. The EDFA module realized a maximum overall signal gain of 33 dB at 1535 nm with a saturated output power of -1 dBm. A maximum saturated output power of 3.9 dBm was obtained at a signal wavelength of 1552 nm. The present EDFA design using a low-cost laser diode for optical disk memory use and a high NA Er-doped fiber has great potential for providing inexpensive, high-performance EDFA's     

Performance limitations of high-power DFB fiber lasers

In this letter, we experimentally study several different configurations of high-power single-frequency sources based on distributed-feedback fiber laser (DFB FL). In particular, we have compared two schemes in terms of pumping efficiency, relative intensity noise (RIN) and optical signal-to-noise ratio (OSNR): directly pumped DFB FLs pumped by a high-power fiber-based pump source (stand-alone DFB FL) and a combination of a DFB FL and a power amplifier (amplified DFB FL). At the output powers below 40 mW, a stand-alone DFB FL has the highest OSNR (> 63 dB) and the lowest RIN (< -165 dB/Hz). The net efficiency of a stand-alone DFB FL can be doubled by using an amplified DFB FL at the expense of degraded OSNR and RIN. It is also shown that RIN below -160 dB/Hz and OSNR > 60 dB can be achieved by an amplified DFB with output power greater than 1 W.     

反射式L波段掺铒光纤放大器增益与噪声指数改善

提出了一种改善反射式L波段掺铒光纤放大器增益和噪声指数的方法,即在放大器的输入端插入一泵浦源,通过提高信号输入端的粒子数反转率实现提高增益和降低噪声指数的目的.通过仔细调整两个泵浦源的输出功率,与单泵浦结构相比,在相同条件下,在1565～1615 nm波长范围内,小信号增益提高了1.5～9.9 dB,噪声指数下降了1.3～9.4 dB.     

Erbium-doped single- and double-pass Ti:LiNbO3 waveguideamplifiers

Single-pass and double-pass Er-diffused Z- and X-cut Ti:LiNbO₃ waveguide amplifiers, optically pumped at λ _p≈1484 nm, have been investigated. With a 48 mm long Z-cut amplifier device, Er-diffusion doped at 1100°C, 6.7 dB (coupled pump power P_p,c=170 mW) and 14.7 dB (P_p,c=90 mW) net small-signal gain have been achieved with a single-pass and a double-pass configuration, respectively, at the signal wavelength λ_s=1531 nm. A Z-cut sample doped at 1135°C showed a considerably improved behavior. 11.3 dB single-pass net small-signal gain has been obtained (P_p,c=170 mW; sample length 5.7 cm). Theoretical calculations predict gain figures up to 20 dB in single-pass and 40 dB in double-pass Er:Ti:LiNbO₃ amplifiers with increased (realistic) lengths of 10 cm     

Operation of erbium-doped fiber amplifiers and lasers pumped withfrequency-doubled Nd:YAG lasers

An optical amplifier consisting of an erbium-doped germanosilicate fiber optically pumped at 532 nm is described. Negligible excited-state absorption at 532 nm allows efficient pumping, enabling a gain of 34 dB at 1536 nm to be obtained for only 25 mW of pump power. The pulsed pump source produces negligible noise on the small signal if the pump repetition rate is above 10 kHz. Pulsed laser operation is achieved by pumping a Fabry-Perot erbium-doped fiber laser with a frequency-doubled Q-switched Nd:YAG laser. Pulses of 0.9-W peak power and 280-ns duration at 1.538-μm were obtained