CN100535730C

CN100535730C - L wave band bilateral backward pump erbium-doped optical fiber amplifier

Info

Publication number: CN100535730C
Application number: CNB2007100476802A
Authority: CN
Inventors: 邢亮; 詹黎; 义理林; 夏宇兴
Original assignee: Shanghai Jiaotong University
Current assignee: Shanghai Jiaotong University
Priority date: 2007-11-01
Filing date: 2007-11-01
Publication date: 2009-09-02
Anticipated expiration: 2027-11-01
Also published as: CN101144956A

Abstract

The present invention relates to a double-way backward pumped L-band erbium-doped optical fiber amplifier, and belongs to the optical communication technical field comprises a tunable laser, an optical circulator, a 980 / L-band-wavelength selecting coupler, an erbium-doped optical fiber, a pumped laser, a reflecting mirror of optical fiber ring and a optical spectrum analyzer, and are connected in the relationship that the optical circulator has three ports, one of the three ports is connected with the tunable laser, another one of the three ports is connected with one end of the erbium-doped optical fiber, the third port of the optical circulator is connected with the optical spectrum analyzer; and the other end of the erbium-doped optical fiber is connected with the public port of the 980 / L-band-wavelength selecting coupler; the 980nm port of the 980 / L-band-wavelength selecting coupler is connected with the pumped laser; the 1550 port of the 980 / L-band-wavelength selecting coupler is connected with the a reflecting mirror of optical fiber ring. The present invention can use lower pump power to achieve higher small-signal gain and low noise index.

Description

The L-band bilateral backward pump erbium-doped optical fiber amplifier

Technical field

What the present invention relates to is the device in a kind of optical communication technology field, specifically is a kind of L-band bilateral backward pump erbium-doped optical fiber amplifier.

Background technology

Along with the accelerated growth of internet data transmission bandwidth demand, traditional C-band (1530nm-1565nm) Erbium-Doped Fiber Amplifier (EDFA) (EDFA) can not meet the demands.Along with the widespread use of dense wavelength division multiplexing system (DWDM), in system, use L-band (1565nm-1610nm) to become more and more important, L-band EDFA has inherent flat gain performance.But owing to the radiation peak of operation wavelength away from erbium ion, the pumping efficiency of L-band Erbium-Doped Fiber Amplifier (EDFA) (EDFA) gain is quite low.Although some technology can effectively improve the L-band signal gain at present, because higher cost or relatively poor noise figure, effect in actual applications is also little.

Find through retrieval the prior art document, the Malaysia S.W.Harun of university, P.Poopalan, " Gain Enhancement in L-Band EDFA Through aDouble-Pass Technique (improving the gain of L-band EDFA with the bilateral technology) " publishes thesis with people such as H.Ahmad, IEEE Photon.Technol.Lett., vol.14, NO.3, MARCH 2002 (being published in the electric Engineering society of U.S. photoelectron technology wall bulletin in March, 2002).The document has reported that the raising of L-band signal gain can realize by the bilateral technology.Promptly the output terminal at Er-doped fiber (EDF) connects a circulator, and amplifying signal is carried out the secondary amplification along importing EDF in the other direction once more, and final amplifying signal utilizes the 3rd output port of first circulator to insert spectroanalysis instrument and measures.This structure uses the 980nm pump laser of 98mW and the long erbium ion concentration of 50m as the EDF of 400ppm, compares with the single-pass structure, when the 1570nm of input-20dBm flashlight, can improve the about 11dB of gain, the about 2dB of noise figure deterioration.Especially when pump power was lower, for example when pump power was 60mW, the noise figure of 1580nm signal was up to 10dB.

Summary of the invention

The present invention is directed to above-mentioned deficiency of the prior art, a kind of L-band bilateral backward pump erbium-doped optical fiber amplifier is provided, make its noise figure in the bilateral light channel structure by using backward pump to improve the gain of L-band signal and reduce signal, effectively improved the gain of L-band, because making, backward pump is recovered utilization to spontaneous radiation behind most C-bands, thereby become the back and be useful influence to the adverse effect of spontaneous radiation, can obtain lower noise figure, the more important thing is that only having changed the pumping direction does not increase any device, the cost of system can effectively be reduced.

The present invention is achieved by the following technical solutions, the present invention includes: tunable laser, optical circulator, 980/L wave band wavelength selective coupler (WSC), Er-doped fiber (EDF), pump laser, fiber optic loop catoptron (FRM), spectroanalysis instrument (OSA), optical circulator has three ports, a port of optical circulator links to each other with tunable laser, another port of optical circulator links to each other with Er-doped fiber one end, the 3rd port of optical circulator links to each other with spectroanalysis instrument, the other end of Er-doped fiber links to each other with the public port of 980/L wave band wavelength selective coupler, the 980nm port of 980/L wave band wavelength selective coupler links to each other with pump laser, and 1550 ports of 980/L wave band wavelength selective coupler link to each other with the fiber optic loop catoptron.

Described tunable laser, its output terminal can connect attenuator, can reduce signal power.

Described pump laser, the pumping light wavelength of its output is 980nm or 1480nm.

Described pump laser, the power of the pump light of its output are 31.8-148.8mW.

Described pump laser can be a pump laser or a plurality of pump laser cascade.

Described fiber optic loop catoptron is that optical circulator or employing are at the terminal plating of Er-doped fiber highly reflecting films.

When the present invention works, the L-band flashlight that is provided by tunable laser is input to a port of optical circulator, the L-band flashlight enters from the output of b end from a end of circulator, the pump laser output power is the pump light of 0-160mw, 980/L wave band wavelength selective coupler is coupled L-band flashlight and pump light and is input to Er-doped fiber, pump light enter will produce behind the Er-doped fiber back to the spontaneous radiation (ASE) of C-band, the fiber optic loop catoptron is with C-band spontaneous emission light and the L-band flashlight reflected back Er-doped fiber that is exaggerated, as the secondary pumping L-band flashlight being carried out secondary amplifies, final amplifying signal light enters the output of c end from the b end of optical circulator, spectroanalysis instrument test input/output signal luminous power, gain and noise figure.

Compared with prior art, the present invention has following beneficial effect: the present invention has changed the position and the direction of 980/L wave band wavelength selective coupler, change the pumping direction, recycle the back to spontaneous radiation as diode pumping, thereby improved pumping efficiency greatly, improve the gain of L-band signal, obtain lower noise figure; The present invention has only changed the pumping direction and has not increased any device, and it is about 60% just to have improved pumping efficiency, and the cost of system can reduce about 50%.

Description of drawings

Fig. 1 structural representation of the present invention

Embodiment

Below in conjunction with accompanying drawing embodiments of the invention are elaborated: present embodiment is being to implement under the prerequisite with the technical solution of the present invention, provided detailed embodiment and concrete operating process, but protection scope of the present invention is not limited to following embodiment.

As shown in Figure 1, present embodiment comprises: tunable laser 1, optical circulator 2, Er-doped fiber 3,980/L wave band wavelength selective coupler 4, pump laser 5, fiber optic loop catoptron 6, spectroanalysis instrument 7, connected mode is: optical circulator 2 has three ports, a port a of optical circulator 2 links to each other with tunable laser 1, the another port b of optical circulator 2 links to each other with Er-doped fiber 3 one ends, the 3rd port c of optical circulator 2 links to each other with spectroanalysis instrument 7, the other end of Er-doped fiber 3 links to each other with the common port of 980/L wave band wavelength selective coupler 4, the 980nm port of 980/L wave band wavelength selective coupler 4 links to each other with pump laser 5, and 1550 ports of 980/L wave band wavelength selective coupler 4 link to each other with fiber optic loop catoptron 6.

Described tunable laser 1, its output terminal can connect attenuator.

Described Er-doped fiber 3, its length are 70m, and its concentration of Er is 240ppm.

Described pump laser 5, the pumping light wavelength of its output is 980nm or 1480nm.

Described pump laser 5, the power of the pump light of its output are 31.8-148.8mW.

Described pump laser 5 can be a pump laser or a plurality of pump laser cascade.

Described fiber optic loop catoptron 6 is that optical circulator or employing are at the terminal plating of Er-doped fiber highly reflecting films.

Described spectroanalysis instrument 7 is the EXFO spectroanalysis instrument.

During present embodiment work, the L-band flashlight that is provided by tunable laser 1 is input to the port a of optical circulator 2, the L-band flashlight enters from port b from the port a of optical circulator 2 and exports, pump laser 5 output powers are the pump light of 31.8-148.8mW, 980/L wave band wavelength selective coupler 4 is coupled L-band flashlight and pump light and is input to Er-doped fiber 3, pump light enter will produce behind the Er-doped fiber 3 back to the spontaneous radiation (ASE) of C-band, fiber optic loop catoptron 6 is with C-band spontaneous emission light and the L-band flashlight reflected back Er-doped fiber 3 that is exaggerated, as the secondary pumping L-band flashlight being carried out secondary amplifies, final amplifying signal light is from the port b entry port c output of optical circulator 2, and spectroanalysis instrument 7 is tested the input/output signal luminous powers, gain and noise figure.

The 1585nm signal of tunable laser 1 input 0.01mW, concrete analysis pump laser 5 output pumping light powers are to the influence of gain and noise reduction, when the power of pump laser 5 output pump lights is 85.8mW, owing to adopted backward pump, the C-band spontaneous radiation can be used as diode pumping after by the fiber optic loop mirror reflects, strengthen pumping efficiency, and because the spontaneous emission light of C-band can be reflected back toward Er-doped fiber 3 is absorbed once more as the secondary pumping of L-band, the power of comparing C-band in output spectrum with prior art will reduce greatly, because most of back is utilized once more to the C-band spontaneous radiation, the output power of 1585nm is 4.4dBm, gain has improved 21.3dB, has also obtained lower noise figure simultaneously; When the power of pump laser 5 output pump lights was 31.8mW, gain had improved 32.4dB, and noise figure is compared with prior art and reduced 21.7dB simultaneously; Along with pump power increases, under the 53.9mw pump power beginning saturated, gain has improved 30.7dB, noise figure has reduced 11.6dB; When the power of pump laser 5 output pump lights was 64.8mw, gain had improved 26.86dB, and noise figure is compared with prior art and reduced 11.6dB simultaneously; When the power of pump laser 5 output pump lights was 148.8mw, saturated gain had improved 6.29dB, and noise figure has increased 2.2dB.

In addition, when tunable laser 1 input signal power is set at 0.01mW, respectively under 85.8mw and 148.8mw pump power condition, investigate signal gain and noise figure variation relation with the signal wavelength of tunable laser 1, under 85.8mw pump power condition, on average, relatively the prior art gain has 20dB to improve and noise figure has 10dB to reduce, obtain maximum gain at 1575nm and promote 27.21dB, noise figure has reduced 15.45dB simultaneously; Under the 148.8mw pumping condition, because gain saturation, the performance boost of gain and noise figure is also not obvious, and the gain that obtains maximum 8.58dB at 1590nm promotes.

Claims

1, a kind of L-band bilateral backward pump erbium-doped optical fiber amplifier, comprise: tunable laser, optical circulator, Er-doped fiber, pump laser, spectroanalysis instrument, optical circulator has three ports, a port of optical circulator links to each other with tunable laser, it is characterized in that, also comprise: 980nm/L wave band wavelength selective coupler, the fiber optic loop catoptron, another port of optical circulator links to each other with Er-doped fiber one end, the 3rd port of optical circulator links to each other with spectroanalysis instrument, the other end of Er-doped fiber links to each other with the public port of 980nm/L wave band wavelength selective coupler, the 980nm port of 980nm/L wave band wavelength selective coupler links to each other with pump laser, and the 1550nm port of 980nm/L wave band wavelength selective coupler links to each other with the fiber optic loop catoptron.

2, L-band bilateral backward pump erbium-doped optical fiber amplifier according to claim 1 is characterized in that, the output terminal of described tunable laser connects attenuator.

3, L-band bilateral backward pump erbium-doped optical fiber amplifier according to claim 1 is characterized in that, the pumping light wavelength of described pump laser is 980nm.

4, according to claim 1 or 3 described L-band bilateral backward pump erbium-doped optical fiber amplifiers, it is characterized in that the power of the pump light of the output of described pump laser is 31.8-148.8mW.

According to claim 1 or 3 described L-band bilateral backward pump erbium-doped optical fiber amplifiers, it is characterized in that 5, described pump laser is a pump laser or a plurality of pump laser cascade.

6, L-band bilateral backward pump erbium-doped optical fiber amplifier according to claim 1 is characterized in that, described fiber optic loop catoptron is an optical circulator.