CN103682959A - Er-Tm-Nd co-doped fiber ultra wideband light source - Google Patents

Abstract

The invention provides an Er-Tm-Nd co-doped fiber ultra wideband light source which comprises a pump laser, a pump coupler and an Er-Tm-Nd co-doped fiber. The Er-Tm-Nd co-doped fiber is the fiber mixed with three rare earth ions of Er, Tm and Nd. The pump laser, the pump coupler and the Er-Tm-Nd co-doped fiber are successively connected. Pump light sent from the pump laser enters the Er-Tm-Nd co-doped fiber through the pump coupler, and broadband light is emitted from an output end. The invention has beneficial effects as follows: the structure is simple and easy to realize; and through appropriate selection of copping concentration of the three rare earth ions of Er, Tm and Nd and fiber length, broadband optical fiber covering all wave optical fiber low-loss window can be obtained so as to bandwidth of all wave optical fiber.

Description

Ultra broadband light source based on erbium thulium neodymium co-doped fiber

Technical field

The invention belongs to optical transport technology field, be specifically related to a kind of ultra broadband light source based on erbium thulium neodymium co-doped fiber.

Background technology

At present, aspect optical transport technology, mainly application is the low loss window of optical fiber from 1280nm to 1625nm.Yet the wideband light source matching can't meet the demand that all-wave covers.Although we can realize wideband light source by coupler, follow the insertion loss of coupler, system power cost raises, and has reduced the transmission performance of whole system.Therefore study the key subject that Wideband light source is optical fiber communication and even biomedical imaging.

Summary of the invention

In order to solve wideband light source in prior art, can not meet the defect that all-wave covers demand, the present invention aims to provide a kind of ultra broadband light source based on erbium thulium neodymium co-doped fiber that can cover the low loss window of all-wave fiber, and concrete technical scheme is as follows:

Ultra broadband light source based on erbium thulium neodymium co-doped fiber, comprise some pump lasers, pumping coupler and erbium thulium neodymium co-doped fiber, and wherein, erbium thulium neodymium co-doped fiber refers to the optical fiber of the erbium that adulterated, thulium, three kinds of rare earth ions of neodymium; The output of some pump lasers is connected with the entrance of pumping coupler respectively, and the outlet of pumping coupler is connected with one end of erbium thulium neodymium co-doped fiber, and the other end of erbium thulium neodymium co-doped fiber is the output of the ultra broadband light source based on erbium thulium neodymium co-doped fiber;

Some pump lasers send the pump light of single wavelength or multi-wavelength, pump light enters erbium thulium neodymium co-doped fiber after being coupled by pumping coupler, pump light makes erbium ion, thulium ion, the neodymium ion in erbium thulium neodymium co-doped fiber launch respectively multiwave spontaneous radiation and the stimulated radiation centered by 1530nm, 1470nm, 1310nm, and producing thus broadband spontaneous emission light, broadband spontaneous emission light is launched by the output of ultra broadband light source.

As prioritization scheme, in described erbium thulium neodymium co-doped fiber, the doping content scope of erbium is 10 ²²-10 ²⁶individual/m ³, the doping content scope of thulium is 10 ²²-10 ²⁶individual/m ³, the doping content scope of neodymium is 10 ²²-10 ²⁶individual/m ³, the proportion between erbium thulium neodymium concentration is (1～10): (1～10): (1～10).

As prioritization scheme, the length of described erbium thulium neodymium co-doped fiber is 0.1-100m.

As prioritization scheme, it is the laser of 800nm or 793nm or 808nm or 980nm pump light that described pump laser adopts output wavelength.

As prioritization scheme, described pumping coupler adopts single-input single-output coupler or the single output of many inputs pumping coupler.

As prioritization scheme, the broadband spontaneous radiation light wavelength of described output transmitting is 1280nm to 1685nm.

Useful technique effect of the present invention is:

(1) of the present invention simple in structure, realize easily, by suitably choosing of parameter, the optical fiber source of the covering all-wave fiber low loss window in broadband can be obtained, thereby the bandwidth of all-wave fiber can be made full use of;

(2) the present invention relates to the selection of erbium, thulium, three kinds of doping concentration of rare earth ion of neodymium, by selecting the ratio of suitable doping content can guarantee that three emission peaks are in substantially concordant state, thereby make the broadband performance of light source more obvious;

(3) the invention still further relates to the power output of pump laser and choosing of fiber lengths, according to adjusting the power output of pump laser and the length of optical fiber, can obtain the different power output of light source.

Accompanying drawing explanation

By reference to the accompanying drawings, by the detailed description of stating below, can more clearly understand above-mentioned and other feature and advantage of the present invention, wherein:

Fig. 1 is structural representation of the present invention;

Fig. 2 is the broadband spontaneous radiation luminous intensity of embodiment 1 output and the graph of a relation of erbium thulium neodymium co-doped fiber length;

Fig. 3 is the broadband spontaneous radiation luminous intensity of embodiment 1 output and the spectrum peak figure of wavelength.

In upper figure, sequence number is:

1-pump laser, 2-pumping coupler, 3-erbium thulium neodymium co-doped fiber.

Embodiment

Below in conjunction with drawings and Examples, the present invention is further illustrated.

Embodiment 1:

As shown in Figure 1, the ultra broadband light source based on erbium thulium neodymium co-doped fiber, comprises pump laser 1, pumping coupler 2 and erbium thulium neodymium co-doped fiber 3, and erbium thulium neodymium co-doped fiber 3 refers to the optical fiber of the erbium that adulterated, thulium, three kinds of rare earth ions of neodymium; The output of pump laser 1 is connected with the entrance of pumping coupler 2, and the outlet of pumping coupler 2 is connected with one end of erbium thulium neodymium co-doped fiber 3, and the other end of erbium thulium neodymium co-doped fiber 3 is the output of the ultra broadband light source based on erbium thulium neodymium co-doped fiber 3.

Pump laser 1 sends the pump light of a single wavelength, pump light enters erbium thulium neodymium co-doped fiber 3 after being coupled by pumping coupler 2, pump light makes erbium ion, thulium ion, the neodymium ion in erbium thulium neodymium co-doped fiber 3 launch respectively multiwave spontaneous radiation and the stimulated radiation centered by 1530nm, 1470nm, 1310nm, and producing thus broadband spontaneous emission light, broadband spontaneous emission light is launched by the output of ultra broadband light source.

Wherein, in erbium thulium neodymium co-doped fiber 3, the doping content of erbium is 1.2 * 10 ²⁵/ m ³, the doping content of thulium is 1.5 * 10 ²⁵/ m ³, the doping content scope of neodymium is 1.2 * 10 ²⁵/ m ³, the length of erbium thulium neodymium co-doped fiber 3 is 7m; It is the laser of 808nm pump light that pump laser 1 adopts output wavelength; Pumping coupler 2 adopts single-input single-output coupler; The broadband light wavelength of output transmitting is 1280nm to 1685nm.In the present embodiment, because 808nm pump light can be absorbed by erbium, thulium, neodymium, and launch respectively the spectrum with certain bandwidth centered by 1530nm, 1470nm and tri-wavelength of 1310nm, when fiber lengths is 7m, three emission center wavelength intensity sizes are substantially equal as can see from Figure 2.As shown in Figure 3, peak strength size is substantially the same for outgoing spectrum now, and bandwidth can cover the overlength bandwidth of 1280～1685nm.

For erbium, thulium, the different levels of doping of three kinds of ions of neodymium and the selection of light length in erbium thulium neodymium co-doped fiber 3, can select according to following method:

First, according to the rare earth ion energy level that emission wavelength is corresponding, set up rate equation, shown in (1)～formula (9);

$\frac{\&PartialD;N_1}{\&PartialD;t}=-W_{13}\&times;N_1+W_{31}\&times;{\mathrm{<figure-callout\; id="3"\; label="N"\; filenames="131112140042.png"\; state="\{\{state\}\}">N</figure-callout>}}_3+A_{31}\&times;N_3-{\mathrm{<figure-callout\; id="2"\; label="C\; cr"\; filenames="131112140042.png"\; state="\{\{state\}\}">C</figure-callout>}}_{\mathrm{cr}}\&times;N_1\&times;N_6-C_{\mathrm{cr}5}\&times;N_1\&times;N_9-C_{\mathrm{et}1}\&times;N_1\&times;N_6-C_{\mathrm{et}2}{\&times;N}_1\&times;N_8---\left(1\right)$

$\frac{\&PartialD;{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="131112140042.png"\; state="\{\{state\}\}">N</figure-callout>}}_2}{\&PartialD;t}=W_{32}\&times;{\mathrm{<figure-callout\; id="3"\; label="N"\; filenames="131112140042.png"\; state="\{\{state\}\}">N</figure-callout>}}_3+A_{32}\&times;N_3-W_{23}\&times;{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="131112140042.png"\; state="\{\{state\}\}">N</figure-callout>}}_2{+\mathrm{<figure-callout\; id="2"\; label="C\; cr"\; filenames="131112140042.png"\; state="\{\{state\}\}">C</figure-callout>}}_{\mathrm{cr}}\&times;N_1\&times;N_6+C_{\mathrm{cr}5}\&times;N_1\&times;N_9---\left(2\right)$

$\frac{\&PartialD;{\mathrm{<figure-callout\; id="3"\; label="N"\; filenames="131112140042.png"\; state="\{\{state\}\}">N</figure-callout>}}_3}{\&PartialD;t}=W_{13}\&times;N_1-W_{31}\&times;N_3-A_{31}\&times;N_3-W_{32}\&times;N_3-A_{32}\&times;{\mathrm{<figure-callout\; id="3"\; label="N"\; filenames="131112140042.png"\; state="\{\{state\}\}">N</figure-callout>}}_3+W_{23}\&times;{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="131112140042.png"\; state="\{\{state\}\}">N</figure-callout>}}_2+C_{\mathrm{et}1}{\&times;N}_1\&times;N_6---\left(3\right)$

$\frac{\&PartialD;N_4}{\&PartialD;t}=-W_{46}\&times;N_4+W_{64}\&times;N_6+A_{64}\&times;N_6-C_{\mathrm{cr}1}\&times;N_4\&times;N_6+C_{\mathrm{et}1}\&times;N_1\&times;N_6-C_{\mathrm{et}3}\&times;N_4\&times;N_8---\left(4\right)$

$\frac{\&PartialD;N_5}{\&PartialD;t}=W_{65}\&times;N_6+A_{65}\&times;N_6-W_{56}\&times;N_5-{2C}_{\mathrm{cr}1}\&times;N_4\&times;N_6+{\mathrm{<figure-callout\; id="3"\; label="C\; cr"\; filenames="131112140042.png"\; state="\{\{state\}\}">C</figure-callout>}}_{\mathrm{cr}}\&times;N_6\&times;{\mathrm{<figure-callout\; id="7"\; label="N"\; filenames="131112140046.png"\; state="\{\{state\}\}">N</figure-callout>}}_7+C_{\mathrm{et}3}\&times;N_4\&times;N_8---\left(5\right)$

$\frac{\&PartialD;N_6}{\&PartialD;t}=W_{46}\&times;N_4-W_{64}\&times;N_6+A_{64}\&times;N_6-W_{65}\&times;N_6+A_{65}\&times;N_6+W_{56}\&times;N_5+C_{\mathrm{cr}1}\&times;N_4\&times;N_6{-\mathrm{<figure-callout\; id="3"\; label="C\; cr"\; filenames="131112140042.png"\; state="\{\{state\}\}">C</figure-callout>}}_{\mathrm{cr}}\&times;N_6\&times;N_7-C_{\mathrm{et}3}\&times;N_4\&times;N_8-C_{\mathrm{et}1}\&times;N_1\&times;N_6---\left(6\right)$

$\frac{\&PartialD;{\mathrm{<figure-callout\; id="7"\; label="N"\; filenames="131112140046.png"\; state="\{\{state\}\}">N</figure-callout>}}_7}{\&PartialD;t}={-W}_{79}\&times;{\mathrm{<figure-callout\; id="7"\; label="N"\; filenames="131112140046.png"\; state="\{\{state\}\}">N</figure-callout>}}_7+W_{97}\&times;{\mathrm{<figure-callout\; id="9"\; label="N"\; filenames="131112140046.png"\; state="\{\{state\}\}">N</figure-callout>}}_9+A_{97}\&times;N_9-W_{78}\&times;{\mathrm{<figure-callout\; id="7"\; label="N"\; filenames="131112140046.png"\; state="\{\{state\}\}">N</figure-callout>}}_7+W_{87}\&times;{\mathrm{<figure-callout\; id="8"\; label="N"\; filenames="131112140046.png"\; state="\{\{state\}\}">N</figure-callout>}}_8+A_{87}\&times;N_8{-\mathrm{<figure-callout\; id="3"\; label="C\; cr"\; filenames="131112140042.png"\; state="\{\{state\}\}">C</figure-callout>}}_{\mathrm{cr}}\&times;N_6\&times;{\mathrm{<figure-callout\; id="7"\; label="N"\; filenames="131112140046.png"\; state="\{\{state\}\}">N</figure-callout>}}_7+C_{\mathrm{et}2}\&times;N_1\&times;{\mathrm{<figure-callout\; id="8"\; label="N"\; filenames="131112140046.png"\; state="\{\{state\}\}">N</figure-callout>}}_8+C_{\mathrm{et}3}\&times;N_4\&times;N_8---\left(7\right)$

$\frac{\&PartialD;{\mathrm{<figure-callout\; id="8"\; label="N"\; filenames="131112140046.png"\; state="\{\{state\}\}">N</figure-callout>}}_8}{\&PartialD;t}=W_{78}\&times;N_7-W_{87}\&times;N_8-A_{87}\&times;{\mathrm{<figure-callout\; id="8"\; label="N"\; filenames="131112140046.png"\; state="\{\{state\}\}">N</figure-callout>}}_8+{2\mathrm{<figure-callout\; id="3"\; label="C\; cr"\; filenames="131112140042.png"\; state="\{\{state\}\}">C</figure-callout>}}_{\mathrm{cr}}\&times;N_6\&times;N_7-C_{\mathrm{et}3}\&times;N_4\&times;{\mathrm{<figure-callout\; id="8"\; label="N"\; filenames="131112140046.png"\; state="\{\{state\}\}">N</figure-callout>}}_8{+C}_{\mathrm{cr}5}{\&times;N}_1\&times;N_9---\left(8\right)$

$\frac{\&PartialD;{\mathrm{<figure-callout\; id="9"\; label="N"\; filenames="131112140046.png"\; state="\{\{state\}\}">N</figure-callout>}}_9}{\&PartialD;t}=W_{79}\&times;N_7-W_{97}\&times;N_9-A_{97}\&times;N_9{-C}_{\mathrm{cr}5}\&times;N_1\&times;N_9---\left(9\right)$

Wherein, N ₁～N ₉for the number of ions on different energy levels, W _ijfor induced transition coefficient, A _ijfor spontaneous transition coefficient, C _etfor energy transfer coefficient, C _crfor cross relaxation coefficient.

N ₁+N ₂+N ₃-N _Nd3+＝0 （10）

N ₄+N ₅+N ₆-N _Tm3+＝0 （11）

N ₇+N ₈+N ₉-N _Er3+＝0 （12）

Formula (10)～formula (12) has guaranteed total number of ions conservation of rare earth ion.

Secondly, set up light along the power delivery equation of spread fiber; Shown in (13)～formula (16):

$\frac{{\mathrm{dP}}_{808}\left(z\right)}{\mathrm{dz}}=[{\mathrm{\&sigma;}}_{31}{N}_3-{\mathrm{\&sigma;}}_{13}{N}_1+{\mathrm{\&sigma;}}_{64}{N}_6-{\mathrm{\&sigma;}}_{46}{N}_4+{\mathrm{\&sigma;}}_{97}{N}_9-{\mathrm{\&sigma;}}_{79}{N}_7-{\mathrm{\&alpha;}}_{808}\left({\mathrm{\&upsi;}}_{808}\right)]P_{808}\left(z\right)---\left(13\right)$

$\frac{{\mathrm{dP}}_{1340}\left(z\right)}{\mathrm{dz}}=[{\mathrm{\&sigma;}}_{32}{N}_3-{\mathrm{\&sigma;}}_{23}{N}_2-{\mathrm{\&alpha;}}_{1340}\left({\mathrm{\&upsi;}}_{1340}\right)]P_{1340}\left(z\right)---\left(14\right)$

$\frac{{\mathrm{dP}}_{1470}\left(z\right)}{\mathrm{dz}}=[{\mathrm{\&sigma;}}_{65}{N}_6-{\mathrm{\&sigma;}}_{56}{N}_5-{\mathrm{\&alpha;}}_{1470}\left({\mathrm{\&upsi;}}_{1470}\right)]P_{1470}\left(z\right)---\left(15\right)$

$\frac{{\mathrm{dP}}_{1530}\left(z\right)}{\mathrm{dz}}=[{\mathrm{\&sigma;}}_{87}{N}_8-{\mathrm{\&sigma;}}_{78}{N}_7-{\mathrm{\&alpha;}}_{1530}\left({\mathrm{\&upsi;}}_{1530}\right)]P_{1530}\left(z\right)---\left(16\right)$

Wherein, P ₈₀₈for pumping light power, P ₁₃₁₀, P ₁₄₇₀, P ₁₅₃₀for the superfluorescence power of different-waveband, α _xfor the attenuation coefficient of different-waveband in optical fiber.

The simultaneous of through-rate equation and power delivery equation calculates, and can obtain the spectrum in different fiber length.Select suitable fiber lengths and make the intensity difference of three emission peaks as far as possible little, the spectrum peak at this moment obtaining is substantially concordant, and bandwidth ratio is larger.In this example, when fiber lengths is 7m, spectrum peak is substantially concordant, as shown in Figure 3.

In the present embodiment, only adopt a pump laser 1, but be not limited to this, also can adopt a plurality of pump lasers, and a plurality of pump laser can be the laser of different wave length, corresponding, pumping coupler adopts the single output of many inputs pumping couplers; After being coupled by pumping coupler, the pump light of some multi-wavelengths of a plurality of pump laser outputs enters erbium thulium neodymium co-doped fiber, make erbium ion, thulium ion, neodymium ion launch respectively multiwave spontaneous radiation and the stimulated radiation centered by 1530nm, 1470nm, 1310nm, and producing thus broadband spontaneous emission light, its operation principle is substantially the same manner as Example 1.

Beneficial effect of the present invention is:

Of the present invention can be by suitable doping concentration of rare earth ion and the fiber lengths chosen, obtain the broadband spectral that bandwidth covers all-wave fiber low loss window, thereby can make full use of the bandwidth of all-wave fiber, promote the development of optical fiber telecommunications system and correlation technique.

The present invention can be with many multi-form realizations, and should not be construed as the restriction of the embodiment being subject in this proposition.

Claims (6)

1. the ultra broadband light source based on erbium thulium neodymium co-doped fiber, is characterized in that, comprise some pump lasers, pumping coupler and erbium thulium neodymium co-doped fiber, and wherein, described erbium thulium neodymium co-doped fiber refers to the optical fiber of the erbium that adulterated, thulium, three kinds of rare earth ions of neodymium; The output of some described pump lasers is connected with the entrance of described pumping coupler respectively, the outlet of described pumping coupler is connected with one end of described erbium thulium neodymium co-doped fiber, and the other end of described erbium thulium neodymium co-doped fiber is the output of the described ultra broadband light source based on erbium thulium neodymium co-doped fiber;

Some described pump lasers send the pump light of single wavelength or multi-wavelength, described pump light enters described erbium thulium neodymium co-doped fiber after being coupled by described pumping coupler, described pump light makes erbium ion, thulium ion, the neodymium ion in described erbium thulium neodymium co-doped fiber launch respectively multiwave spontaneous radiation and the stimulated radiation centered by 1530nm, 1470nm, 1310nm, and producing thus broadband spontaneous emission light, described broadband spontaneous emission light is launched by the output of described ultra broadband light source.

2. the ultra broadband light source based on erbium thulium neodymium co-doped fiber according to claim 1, is characterized in that, in described erbium thulium neodymium co-doped fiber, the doping content scope of erbium is 10 ²²-10 ²⁶individual/m ³, the doping content scope of thulium is 10 ²²-10 ²⁶individual/m ³, the doping content scope of neodymium is 10 ²²-10 ²⁶individual/m ³, the proportion between erbium thulium neodymium concentration is (1 ~ 10): (1 ~ 10): (1 ~ 10).

3. the ultra broadband light source based on erbium thulium neodymium co-doped fiber according to claim 2, is characterized in that, the length of described erbium thulium neodymium co-doped fiber is 0.1-100m.

4. the ultra broadband light source based on erbium thulium neodymium co-doped fiber according to claim 1, is characterized in that, it is the laser of 800nm or 793nm or 808nm or 980nm pump light that described pump laser adopts output wavelength.

5. the ultra broadband light source based on erbium thulium neodymium co-doped fiber according to claim 1, is characterized in that, described pumping coupler adopts single-input single-output coupler or the single output of many inputs pumping coupler.

6. the ultra broadband light source based on erbium thulium neodymium co-doped fiber according to claim 1, is characterized in that, the wave-length coverage of the broadband spontaneous emission light of the output transmitting of described ultra broadband light source is 1280nm to 1625nm.

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