AU640073B2 - Optical amplifier - Google Patents
Optical amplifier Download PDFInfo
- Publication number
- AU640073B2 AU640073B2 AU10374/92A AU1037492A AU640073B2 AU 640073 B2 AU640073 B2 AU 640073B2 AU 10374/92 A AU10374/92 A AU 10374/92A AU 1037492 A AU1037492 A AU 1037492A AU 640073 B2 AU640073 B2 AU 640073B2
- Authority
- AU
- Australia
- Prior art keywords
- fibre
- light
- length
- pump light
- signal amplifying
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Ceased
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
- H01S3/06—Construction or shape of active medium
- H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
- H01S3/067—Fibre lasers
- H01S3/06754—Fibre amplifiers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/09—Processes or apparatus for excitation, e.g. pumping
- H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
- H01S3/094—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
- H01S3/094003—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light the pumped medium being a fibre
- H01S3/094011—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light the pumped medium being a fibre with bidirectional pumping, i.e. with injection of the pump light from both two ends of the fibre
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Optics & Photonics (AREA)
- Lasers (AREA)
- Optical Communication System (AREA)
- Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)
- Light Guides In General And Applications Therefor (AREA)
- Optical Filters (AREA)
Abstract
Pumped light can cause disturbances in the transmission path in optical amplifiers for amplifying light signals which are transmitted in light waveguides (4, 8), are supplied via a light waveguide coupler (5) into a light-signal amplifying fibre element (3) and are not completely absorbed therein. According to the invention, there is a pumped-light absorption fibre element (7), containing a ytterbium, behind the light-signal amplifying fibre element (3), which has a large absorption cross-section in the wavelength band from 900-1050 nm, in which the wavelength of the pumped light, which comes from a laser, lies. <IMAGE>
Description
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ORIGINAL
COMPLETE SPECIFICATION STANDARD PATENT I inetion Title: "OPTICAL AMPLIFIER" The Following statement is a full deoscription of' this invention, including the bcst method of perorming it known to us:- 1 I 2 This invention relates to an optical amplifier for amplifying light signals wherein a first fibre optic coupler for coupling in a first pump light is followed by a light signal amplifying length of fibre in which the light signals are amplifiable by the pump light, and wherein the light signal amplifying length of fibre is followed by a filter for absorbing the pump light.
Optical amplifiers serve to amplify light signals that are transmitted in optical waveguides and are weakened by atten uation, so that they must be ampliJ-:.. To amplify the light signals, the optical amplifiers contain a light signal amplifying length of fibre. The light signal amplifying length of fibre contains a laser-active substance, eg., an erbium compound, which is excited by pump light from a laser, eg., a semiconductor laser.
An optical amplifier of this type with an erbium doped light signal amplifying length of fibre is known from Electronics Letters 26, (1990), pp. 532-33. In the direction of transmission of the light signals, the light signal amplifying length of fibre 15 of the optical amplifier is preceded by a fibre optic coupler, through which pump light is irradiated from a multi-quantum well semiconductor laser into the light signal amplifying length of fibre.
In the direction of transmission of the light signals, the light signal amplifying length of fibre is followed by a filter, which is designed as an interference filter. This 20 serves to absorb the pump light that was not absorbed in the light signal amplifying S length of fibre and whose transmission in the optical waveguide to a receiving device S is to be suppressed, because it can cause problems.
Optical amplifiers which, instead of an interferometric filter, contain an optical isolator are known from other publications, eg. Electronics Letters 26, (1990) pp.
25 66-67. The optical isolator serves, on t he one hand, for suppression of back reflections of the light signals but, on the other hand, it also absorbs light of other wavelengths, eg., the pump light. It thus also acts as a filter.
The interferometric filter and the optical isolator have the disadvantage of also causing an attenuation of the light signals, particularly of the light signals with a wavelength of 1300 nm.
It is an object of the present invention to create an optical amplifier of the aforementioned type indicated with a filter that will strongly absorb the pump light without weakening the light signals.
It is another object of the present invention to create a process for the operation of an optical amplifier with a filter of this type.
i y- I~ lgY~. r According to a first aspect of the present invention there is provided an optical amplifier according to the invention having the further advantage that the pump light absorbing length of fibre contained in it and serving as a filter can be easily incorporated into the transmission section of the light signals, because it is a length of fibre, just like the light signal amplifying length of fibre. It can be spliced with this by means of the known splicing process, and also with the fibre optic coupler or with the optical waveguide for transmission of the light signals.
In an advantageous further development of the invention, two pump light absorbing lengths of fibre are present. In that case, pump light can be fed from two lasers into the light signal amplifying length of fibre. In this case, each of the two pump light absorbing lengths of fibre carries out two functions: it absorbs the pump light of the one laser in the forward direction and the pump light of the other laser, which has been back-reflected at a point with a jump in the refractive index, eg. at a .egg, splice point, in the reverse direction.
15 The invention will be described below in greater detail in examples, by means of drawings. Insofar as the invention relates to a process for operation of the optical amplifier, it is explained in connection with the description of the optical amplifier.
In the drawings: Figure 1 represents an optical amplifier with a single pump light absorbing 20 length of fibre, and Figure 2 shows an optical amplifier with two pump light absorbing lengths of fibre.
Described below is an optical amplifier (Figure 1) with an input I and an output 2, to provide an indication of the (lirection in which the light signals are transmitted 25 in the optical amplifier.
The light signals can, of course, also be transmitted in the optical amplifier in the "reverse direction". In this case, the input I becomes the output and the output 2 becomes the inout.
The optical amplifier (Figure behind the input I, shows a light signal amplifying length of fibre 3 which, for example contains an erbium compound as a laseractive substance. Between the input 1 and the light signal amplifying length of fibre 3, the light signals pass through a first optical waveguide 4 and a fibre optic coupler The light signal amplifying length of fibre 3 is spliced with the fibre optic coupler In order to achieve a particularly high optical amplification of the light signals, it is of advantage if its core has a smaller cross section than the core of the fibre optic coupler 5. On the basis of this, the light signal amplifying length of fibre 3 has a smaller overall cross section than the fibre optic coupler 5. The latter connects the light signal amplifying length of fibre 3 with a laser 6, which is preferably a semiconductor laser, eg., an InGaAs/AIGaAs laser, which ent's pump light with a wavelength within the range of 960-l000nm.
Behind the light signal amplifying length of fibre 3 in the direction of light propagation, a pump light absorbing length of fibre 7 is spliced to the length of fibre 3. The length of fibre 7 contains an ytterbium (Yb 3 compound, which strongly absorbs in the wavelength range of 900-1050 nm, ie., in the wavelength range of the pump light. In this process, an excitation from the energy level 2
F
7 2 to the energy level 2 F5/2 takes place.
Behind the pump light absorbing length of fibre 7 there follows a second optical waveguide 8, which the light signals leave through the output 2. In accordance with the optical amplifier explained with reference to Figure 1, the pump light absorbing 15 length of fibre 7 has the same cross section as the optical waveguide 8 that follows it.
However, the pump light absorbing length of fibre 7 can also have the same cross section as the light signal amplifying length of fibre 3.
According to a further developmert, which is explained with reference to Figure 2, in addition to the components already contained in Figure 1, there is also present 20 another fibre optic coupler 9, which is disposed between the light signal amplifying length of fibre 3 and the pump light absorbing length of fibre 7. Through this, pump light coming from a laser 10 is fed into the light signal amplifying length of fibre 3 between the optical waveguide 4 and the fibre optic coupler 5, in a direction opposite to that of the pump light coming from the lascr 6. The laser 10 is preferably designed 25 in exactly the same way as the laser 6.
An additional pump light absorbing length of fibre 11 is therefore present, by means of which the pump light coming from the laser 10 is essentially absorbed. A small part of this pump light is reflected at the boundary surfaces between the pump light absorbing length of fibr I11, the fibre optic couplers 5, 9, and the light signal amplifying length of fibre 3 and passes into the pump light absorbing length of fibre 7, where it is then absorbed.
Correspondingly, a small part of the pump light coming from the laser 6 is reflected at the boundary surfaces between the pump light absorbing length of fibre 7, the fibre optic couplers 5, 9, and the tight signal amplifying length of fibre 3 and passes into the pump light absorbing length of fibre 11, where it is then absorbed.
the ibr opic oupers 9 an th iiht sgna amlifinglengh o fire an I II Icl The pump light absorbing length of fibre 7 advantageously has the same cross section as the adjoining optical waveguide 8 and optical coupler 9, The pump light absorbing length of fibre 11 preferably has the same cross section as the adjoining optical waveguide 4 and optical coupler In this manner, the pump light absorbing lengths of fibre 7, 11 can be simply spliced with the optical waveguides 4, 8 and the fibre optic couplers 5, 9.
It also applies for the optical amplifier according to Figure 2 that the light signals can be transmitted in both directions in the light signal amplifying length of fibre 3, the fibre optic couplers 5, 9, and the optical waveguides 4, 8.
0 2 **4 0
*O
Claims (8)
1. An optical amplifier for amplifying light signals wherein a first fibre optic coupler for coupling in a first pump light is followed by a light signal amplifying length of fibre in which the light signals arc amplifiable by the pump light, and wherein the light signal amplifying Icngth of fibre is followed by a filter for absorbing the pump light, and wherein the filter is arranged as a pump light absorbing length of fibre which contains ytterbium.
2. An optical amplifier as claimed in claim I, wherein the pump light absorbing length of fibre is preceded by a second fibre optic coupler for coupling a second pump 10 light into the light signal amplifying length of fibre, and that the first fibre optic coupler is preceded by an additional pump light absorbing length of fibre.
3. An optical amplifier as claimed in claim 1, wherein the pump light absorbing length of fibre has the same cross section as the light signal amplifying length of fibre.
4. An optical, amplifier as claimed in claim 1, wherein the pump light absorbing 15 length of fibre has the same cross section as an optical waveguide disposed behind the pump light absorbing length of fibre.
An optical amplifier as claimed in claim 2, wherein the pump light absorbing lengths of fibre have the same cross section as the adjoining optical waveguides and the adjoining fibre optic couplers, 20
6. A method of operating an optical amplifier for amplifying light signals wherein the: light signals are amplified in a light signal amplifying length of fibre by a first to**: pump light, and wherein the first pump light not used in the light signal amplifying length of fibre is absorbed in a first ytterbium-containing pump light absorbing length S of fibre. 25
7. A method of operating an optical almplifier for amplifying light signals as claimed in claim 6, wherein in the light signal amplifying length of fibre, the light signals are also ampli'ied by a second pump light, and that the second pump light not used in the light signal amplifying length of fibre is absorbed in a second ytterbium- containing pump light absorbing length of fibre.
8. An optical amplifier substantially as herein described with reference to Figures 1 2 of the accompanying drawings. DATED THIS SIXTEENTH DAY OF JANUARY 1992 ALCATEL N.V. _e t t ABSTRACT Pump light which, in optical amplifiers for amplifying light signals that are transmitted in optical waveguides 8) is fed through a fibre optic coupler into a light signal amplifying length of fibre and is not completely absorbed therein, can cause problems in the transmission section. According to the invention, the light signal amplifying length of fibre is fol- lowed by an ytterbium-containing pump light absorbing length of fibre which has a large absorption cross-section in the wavelength range of 900-1050 nm, in which the wavelength of the pump light coming from a laser is located. Figure 1. S *S me S 0 I ti t 't
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4102648A DE4102648A1 (en) | 1991-01-30 | 1991-01-30 | OPTICAL AMPLIFIER |
| DE4102648 | 1991-01-30 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU1037492A AU1037492A (en) | 1992-08-06 |
| AU640073B2 true AU640073B2 (en) | 1993-08-12 |
Family
ID=6423958
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU10374/92A Ceased AU640073B2 (en) | 1991-01-30 | 1992-01-21 | Optical amplifier |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0497140B1 (en) |
| JP (1) | JP3252148B2 (en) |
| AT (1) | ATE104094T1 (en) |
| AU (1) | AU640073B2 (en) |
| CA (1) | CA2060287C (en) |
| DE (2) | DE4102648A1 (en) |
| ES (1) | ES2055621T3 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5216728A (en) * | 1991-06-14 | 1993-06-01 | Corning Incorporated | Optical fiber amplifier with filter |
| DE4446524A1 (en) * | 1994-12-24 | 1996-06-27 | Sel Alcatel Ag | Fiber optic amplifier |
| DE19647488A1 (en) * | 1996-11-16 | 1998-05-20 | Alsthom Cge Alcatel | Optical amplifier for optical transmission system |
| DE19723267A1 (en) | 1997-06-03 | 1998-12-10 | Heidelberger Druckmasch Ag | Method and arrangement for reducing the pump light at the exit of a fiber laser |
| WO2003084007A1 (en) * | 2002-03-28 | 2003-10-09 | Fujitsu Limited | Optical device having loss compensation function and optical amplifier for loss compensation |
| US7940453B2 (en) | 2006-08-07 | 2011-05-10 | Pyrophotonics Lasers Inc. | Fiber amplifiers and fiber lasers with reduced out-of-band gain |
| CN109038189B (en) * | 2018-07-27 | 2019-12-31 | 武汉光迅科技股份有限公司 | Double 980 pump laser pair pump structure for EDFA |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU2571292A (en) * | 1991-09-02 | 1993-04-05 | Nkt Research Center A/S | A method of suppressing relative intensity noise in coherent optical systems, such as communication receivers |
-
1991
- 1991-01-30 DE DE4102648A patent/DE4102648A1/en not_active Withdrawn
-
1992
- 1992-01-15 EP EP92100571A patent/EP0497140B1/en not_active Expired - Lifetime
- 1992-01-15 DE DE92100571T patent/DE59200103D1/en not_active Expired - Fee Related
- 1992-01-15 ES ES92100571T patent/ES2055621T3/en not_active Expired - Lifetime
- 1992-01-15 AT AT92100571T patent/ATE104094T1/en not_active IP Right Cessation
- 1992-01-21 AU AU10374/92A patent/AU640073B2/en not_active Ceased
- 1992-01-27 JP JP01183092A patent/JP3252148B2/en not_active Expired - Fee Related
- 1992-01-29 CA CA002060287A patent/CA2060287C/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU2571292A (en) * | 1991-09-02 | 1993-04-05 | Nkt Research Center A/S | A method of suppressing relative intensity noise in coherent optical systems, such as communication receivers |
Also Published As
| Publication number | Publication date |
|---|---|
| DE59200103D1 (en) | 1994-05-11 |
| AU1037492A (en) | 1992-08-06 |
| ATE104094T1 (en) | 1994-04-15 |
| CA2060287C (en) | 2001-07-24 |
| CA2060287A1 (en) | 1992-07-31 |
| JP3252148B2 (en) | 2002-01-28 |
| DE4102648A1 (en) | 1992-08-06 |
| JPH04303980A (en) | 1992-10-27 |
| EP0497140A1 (en) | 1992-08-05 |
| EP0497140B1 (en) | 1994-04-06 |
| ES2055621T3 (en) | 1994-08-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MK14 | Patent ceased section 143(a) (annual fees not paid) or expired |