GB2344210A - A parallel optical fibre amplifier - Google Patents
A parallel optical fibre amplifier Download PDFInfo
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- GB2344210A GB2344210A GB9927613A GB9927613A GB2344210A GB 2344210 A GB2344210 A GB 2344210A GB 9927613 A GB9927613 A GB 9927613A GB 9927613 A GB9927613 A GB 9927613A GB 2344210 A GB2344210 A GB 2344210A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/29—Repeaters
- H04B10/291—Repeaters in which processing or amplification is carried out without conversion of the main signal from optical form
- H04B10/293—Signal power control
- H04B10/294—Signal power control in a multiwavelength system, e.g. gain equalisation
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
- H01R13/02—Contact members
- H01R13/10—Sockets for co-operation with pins or blades
- H01R13/11—Resilient sockets
-
- 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
- H01S2301/00—Functional characteristics
- H01S2301/02—ASE (amplified spontaneous emission), noise; Reduction thereof
-
- 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
- H01S3/06762—Fibre amplifiers having a specific amplification band
- H01S3/06766—C-band amplifiers, i.e. amplification in the range of about 1530 nm to 1560 nm
-
- 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
- H01S3/06762—Fibre amplifiers having a specific amplification band
- H01S3/0677—L-band amplifiers, i.e. amplification in the range of about 1560 nm to 1610 nm
-
- 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
-
- 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
- H01S3/23—Arrangements of two or more lasers not provided for in groups H01S3/02 - H01S3/22, e.g. tandem arrangements of separate active media
- H01S3/2383—Parallel arrangements
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- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Optics & Photonics (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Lasers (AREA)
- Connections By Means Of Piercing Elements, Nuts, Or Screws (AREA)
Abstract
A parallel optical fibre amplifier comprises first and second erbium-doped amplifier stages (EDFA) 110, 120. There is a means for re-using spontaneous emission light emitted from the first EDFA 110 stage as a secondary pumping source for the second EDFA stage 120. The second EDFA stage 120 may comprise; an optical pumping means 126, a first optical fibre portion 124 which is optically pumped, and a second optical fibre portion 122 which is not optically pumped. The spontaneous emission light from the first optical fibre portion 124 may be re-used as a pumping source for the second optical fibre portion 122. The first and second stage EDFA's may be either a C-band or an L-band EDFA. The re-using means may comprise; a circulator 150 for receiving spontaneous emission light from the first EFDA stage 110, a connecting optical fibre 160 for transmitting the received spontaneous emission light to the second EDFA stage, and an optical WDM coupler 170 connected between the connecting optical fibre 160 and the second EDFA stage 120. The optical fibres amplifiers may be silica-based. Preferably, amplified spontaneous emission (ASE) light from a C-band EDFA stage and reverse ASE light emitted from an L-band EDFA are re-used in the L-band EDFA stage.
Description
PARALLEL OPTICAL FIBRE AMPLIFIER
BACKGROUND OF THE INVENTION
The present invention relates to an optical device for optical communications, and more particularly in a preferred embodiment to a parallel optical fibre amplifier having a configuration capable of re-using amplified spontaneous emission (ASE) light as a secondary pumping source.
Recently, Er"-doped fibre amplifiers (EDFAs) having a wide gain band have been proposed to solve problems involved in wavelength division multiplexed (WDM) systems due to a continued increase in the capacity of such WDM systems.
For practical systems configured using such EDFAs, it has been regarded that it is inevitably necessary, in terms of the costs and applicability, to use silica-based EDFAs, of a typical C-band (a wavelength band of 1530 to 1560 nm) or an L-band of long wavelengths, coupled together in parallel, in spite of the fact that optical fibre amplifiers made of new materials, for example, telluritebased EDFAs, have been developed. There are many pending problems to be solved in association with L-band EDFAs because of the short historical development of L-band
EDFAs. For example, L-band EDFAs have a low power conversion efficiency resulting in a requirement for highpower pumps. Due to such a low pumping efficiency of Lband EDFAs, silica-based optical fibre amplifiers having an L-band EDFA parallel connection configuration have limited use in wide bands. In order to provide a means for achieving an improvement in the power conversion efficiency of L-band EDFAs, the inventors have developed a technique for re-using useless amplified spontaneous emission (ASE) light as a secondary pumping source for an
EDF region not pumped. In accordance with this technique, a considerable improvement in performance is exhibited.
This technique is discussed in Korean Patent Application
No. 98-34370.
SUMMARY OF THE INVENTION
The present invention provides a parallel optical fibre amplifier comprising a first EDFA stage, and a second EDFA stage connected to the first EDFA stage in parallel, further comprising means for re-using spontaneous emission light emitted from the first EDFA stage and/or the second
EDFA stage as a secondary pumping source for the second
EDFA stage.
The second EDFA stage may have a gain wavelength band different from that of the first EDFA stage.
The first EDFA stage may comprise a C-band EDFA, and the second EDFA stage may comprise an L-band EDFA. It has been found that, in this case, it is possible to embody a parallel optical fibre amplifier capable of exhibiting a high power conversion efficiency at relatively wide wavelength bands.
The re-using means may comprise a circulator for receiving the spontaneous emission light from the first EDFA stage, a connecting optical fibre for transmitting the received spontaneous emission light to the second EDFA stage, and a wavelength selective coupler connected between the connecting optical fibre and the second EDFA stage in such a fashion that the spontaneous emission light from the connecting optical fibre is transmitted to the second EDFA stage.
The second EDFA stage may comprise optical pumping means, and a first optical fibre portion adapted to be optically pumped by the optical pumping means. Optionally, a second optical fibre portion, adapted not to be pumped by the optical pumping means may be provided. The optical pumping means of the second EDFA stage may then be arranged between the first and second optical fibre portions.
The optical pumping means conducts a forward and/or backward pumping operation for the first optical fibre portion. In this case, a more efficient optical amplification for the second EDFA stage can be achieved because the second EDFA stage is supplied with useless reverse ASE light from its first optical fibre portion, in addition to useless reverse ASE light from the first EDFA stage.
Preferably, the first and/or second EDFA stages comprise silica-based optical fibre.
Preferably, the invention provides an optical fibre amplifier which exhibits a high power conversion efficiency in wide wavelength bands.
Improved efficiency is obtained in the optical fibre amplifier of the invention, even when no second optic fibre portion is provided in the second EDFA stage.
Improved efficiency is obtained, in any case, by using the reverse ASE light of the first stage EDFA as a subsidiary pump source for the second stage EDFA. The improvement is even more pronounced when an unpumped second optic fibre portion is included in the second EDFA stage.
The first EDFA stage may be adapted to operate in the Cband. The second EDFA stage may be adapted to operate in the L-band.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described, by way of example only, with reference to the accompanying drawings in which:
Fig. la is a schematic view illustrating a first parallel optical fibre amplifier according to an embodiment of the present invention;
Fig. lb is a schematic view illustrating a second parallel optical fibre amplifier according to an embodiment of the present invention;
Fig. 2 is a graph depicting an optical output spectrum of the general parallel optical fibre amplifier, shown in
Fig. la, for a saturated input signal of 0 dBm where the general parallel optical fibre amplifier has no EDF portion adapted not to be pumped;
Fig. 3 is a graph depicting reverse ASE spectrums respectively observed for C-band and L-band EDFAs when an input saturated signal of 0 dBm is input;
Fig. 4a is a graph depicting the measurement results for the 1595 nm saturated signal output intensity (along with the 1540 nm saturated signal output intensity) and the power conversion efficiency of the entire system obtained in the general parallel optical fibre amplifier of Fig. la and the parallel optical fibre amplifier according to the embodiment of the present invention while varying the length of the EDF portion adapted not to be pumped, respectively; and
Fig. 4b is a graph depicting noise factors respectively measured for the parallel optical fibre amplifiers of
Figs. la and lb.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Reference will now be made in greater detail to the preferred embodiments of the present invention.
The following description will be made while comparing different embodiments of parallel optical fibre amplifiers, in terms of the configuration and performance, for easy identification of the effects obtained by the present invention.
Referring to Fig. la, a C-band silica-based EDFA stage 110 and an L-band silica-based EDFA stage 120 are connected to each other in parallel by C-band/L-band WDM couplers 130 and 132. The C-band EDFA stage 110 includes a C-band EDF 112 having a desired length, and a first laser diode 114 for outputting pumping light of 980 nm adapted to pump the
C-band EDF 112. The first laser diode 114 is coupled to the C-band EDF 112 by a first WDM coupler 116.
On the other hand, the L-band EDFA stage 120 includes two
EDFs 122 and 124 connected together in series, and a second laser diode 126 coupled between the EDFs 122 and 124 and adapted to output pumping light of 980 nm. The second laser diode 126 is coupled to the EDF 124 by a second WDM coupler 128 so that it forwardly pumps the EDF 124. By virtue of such an arrangement of the second laser diode 126, the EDF 122 is not pumped by the second laser diode 126.
In order to guide the travel of optical signals in one direction in the optical fibre amplifier, optical isolators 140,142, and 144 are arranged at the input terminal of the optical fibre amplifier, the output terminal of the C-band EDFA stage 110, and the output terminal of the L-band EDFA stage 120, respectively. The reason why the optical fibre amplifier is configured as mentioned above is not only to obtain gains in wide wavelength bands by virtue of the use of the C-band and Lband EDFA stages 110 and 120, but also to allow reverse
ASE light emitted from the EDF 124 back towards EDF 122, being pumped, in the L-band EDFA state 120 to serve as a secondary pumping source for the EDF 122, thereby achieving an enhancement in power conversion efficiency.
Fig. lb is a schematic view illustrating a further parallel optical fibre amplifier according to an embodiment of the present invention. In Fig. lb, elements respectively corresponding to those in Fig. la are denoted by the same reference numerals.
Referring to Fig. lb, reverse ASE light emerging from the
C-band EDFA stage 110 is supplied to the EDF 122, which is not pumped by the second laser diode 126, via an optical circulator 150, a connecting optical fibre 160, and a Cband/L-band WDM coupler 170. In accordance with this configuration according to an embodiment of the present invention, therefore, the EDF 122, which is not pumped by the second laser diode 126, uses both the useless reverse
ASE light emitted from the EDF 124 which is pumped by the second laser diode 126 and the useless reverse ASE light emitted from the C-band EDFA stage 110, thereby achieving an improvement in power conversion efficiency.
Although the EDF 122, not to be pumped, has been described as being included in the L-band EDFA stage 120 in the illustrated embodiment of the present invention, the optical fibre amplifier of the present invention is not limited to this configuration. This is apparent from the following description, made in conjunction with Figs. 4a and 4b, describing the fact that the intended effects of the present invention are obtained even when the length of the EDF 122 is zero.
The reverse ASE light from the C-band EDFA 110 provides a subsidiary pumping effect, which improves the efficiency of the L-band EDFA 120 regardless of its own pumping state.
Now, a comparison between the optical fibre amplifiers of
Figs. la and lb, in terms of the operation, will be made.
For comparison, EDFs having the same configuration are used in both cases of Fig. la and lb. Each of the EDFs used is comprised of a commercially available Al-codoped optical fibre exhibiting a maximum absorption coefficient of 4.5 dB/m at a wavelength of 1530 nm. In order to observe a variation in power conversion efficiency depending on the length of the EDF 122 adapted not to be pumped by the second laser diode 126, a measurement was made for the power conversion efficiency under condition in which respective lengths of the C-band EDF 112 and Lband EDF 124, which are adapted to be pumped by their own pumps, respectively, are fixed to 20 m and 135 m, while varying the length of EDF 122 to 0 m, 5 m, 15 m, 20 m, 25 m, and 35 m, respectively. The first and second laser diodes 114 and 126, which conduct a pumping operation at a wavelength of 980 nm, had output power of 85 mW. Two external resonating lasers, which are tuned to 1540 nm and 1595 nm respectively, were also used along with an optical spectrum analyser in order to evaluate respective gains of the optical amplifiers. Input signals having an intensity of 0 dBm at the two wavelengths are input to each optical fibre amplifier, respectively, so as to measure the small signal gain, noise factor, intensity of saturated power, and power conversion efficiency. Loss resulting from the circulator and loss resulting from the C-band/L-band
WDM coupler were 0.6 dB and 0.3 dB, respectively.
Fig. 2 is a graph depicting an optical output spectrum of the general parallel optical fibre amplifier, shown in
Fig. la, for a saturated input signal of 0 dBm where the general parallel optical fibre amplifier has no EDF portion adapted not to be pumped. Referring to Fig. 2, it can be found that the bandwidth of the optical gain resulting from the ASE spectrum is wide, i. e., 80 nm or more. For signals of 1540 nm and 1595 nm, the intensities of saturated outputs were 14.75 dBm and 10.66 dBm, respectively, as illustrated.
In order to identify the fact that there is reverse ASE light having an intensity enough to provide an improvement in power conversion efficiency, the intensity of the reverse ASE light emitted from each of the C-band EDFA and
L-band EDFA was measured using another circulator. Fig. 3 is a graph depicting reverse ASE spectrums respectively observed for the above two EDFAs when an input saturated signal of 0 dBm is input. The spectrum measurement was conducted using an optical spectrum analyser with a resolution of 0.2 nm. Each of the spectra exhibited a peak, in the vicinity of wavelengths of 1540 nm and 1595 nm, respectively, as shown in Fig. 3. These peaks may result from a Rayleigh back-scattering of each input signal. The intensity of the reverse ASE light emitted from the C-band EDFA was 1.5 mW. This value is relatively low, as compared to the intensity of the reverse ASE light emitted from the L-band EDFA, that is, 17 mW. However, the ASE intensity of about 1.5 mW provides an improvement in L-band amplification efficiency. This may be identified by referring to the article issued by A. Mori and entitled"Tellurite-Based EDFA for Wide-Band
Communications"in OFC Technical Summery wAl, 1998, pp 97.
The article discloses use of signals of 1550 nm having an intensity lower than 1. 5 mW as a pumping source for Lband amplification.
Fig. 4a depicts the measurement results for the 1595 nm saturated signal output intensity (along with the 1540 nm saturated signal output intensity) and the power conversion efficiency of the entire system obtained in the parallel optical fibre amplifier of Fig. la (hereinafter, referred to as a"first type parallel configuration") and the parallel optical fibre amplifier of Fig. lb (hereinafter, referred to as a"second type parallel configuration") while varying the length of the
EDF portion adapted not to be pumped, respectively.
Referring to Fig. 4a, it can be found that the output intensity in the first type parallel configuration exhibits a high dependency on the length of the EDF portion adapted not to be pumped in such a fashion that it increases as the length of the EDF portion adapted not to be pumped increases. In the first type parallel configuration, an improvement in the overall pumping efficiency ranging from 24.4 W to 31.3 % was obtained.
This improvement results from the fact that the useless reverse ASE light emitted from the EDF portion, being pumped, of the L-band EDFA stage is re-used in the EDF portion adapted not to be pumped. On the other hand, in the second type parallel configuration, a higher 1595 nm saturated signal output intensity and a higher power conversion efficiency were exhibited, as compared to the first type parallel configuration. In the case of the second type parallel configuration, the 1595 nm saturated signal output intensity was enhanced to 16. 8 mW even when there is no EDF portion adapted not to be pumped. Under the same condition, the first type parallel configuration exhibited 11.6 mW.
The reason why the second type parallel configuration exhibits superior results over the first type parallel configuration is because the reverse ASE light emitted from the C-band EDFA stage is effectively re-used in the second type parallel configuration, in addition to the reverse ASE light from the pumped portion 124 of the second EDFA stage 120.. It is to be noted in Fig. 4a that the power conversion efficiency increasing effect obtained by the additional re-use of the reverse ASE light emitted from the C-band EDFA stage decreases gradually as the length of the EDF portion adapted not to be pumped increases. This phenomenon results from the fact that the intensity of the reverse ASE light emitted from the C-band
EDFA is lower than that from the L-band EDFA. On the basis of the above mentioned results, it is possible to design a parallel optical fibre amplifier configuration capable of achieving a most efficient use of pump intensity. In accordance with the present invention, therefore, the EDF portion adapted not to be pumped is arranged upstream from the pumping laser diode in such a fashion that it re-uses the intensity of reverse ASE light resulting from the pumping operation of the pumping laser diode 126.
According to certain features of an embodiment of the present invention, a circulator and a WDM coupler are introduced, in order to inject reverse ASE light of the first (C-band) EDFA to the second (L-band) EDFA, so that reverse ASE light can be used as a secondary (subsidiary) pumping light source.
In order to measure the changes of noise factor resulting from the low and limited intensity of the reverse ASE light emitted from the C-band EDFA stage, respective noise factors of the first and second type parallel configurations were measured. The measured results are depicted in Fig. 4b. Referring to Fig. 4b, it can be found that the second type parallel configuration exhibits an internal noise factor lower than that of the first type parallel configuration by about 0.3 dB. This low noise factor of the second type parallel configuration may result from the fact that the reverse ASE light emitted from the C-band EDFA stage not only serves as a pumping source for amplifying the signal of 1600 nm, but also serves as photon seeds for ASE light of 1600 nm. It was also observed, for both parallel configurations, that an increase in noise factor occurs as the length of the EDF portion adapted not to be pumped increases. This may result from a decrease in average population inversion occurring due to a decrease in the intensity of the ASE light per length in the EDF portion adapted not to be pumped.
As apparent from the above description, the present invention applies the technique for re-using useless reverse ASE light to a parallel optical fibre amplifier.
In a particular embodiment, the two parallel stages of such a parallel optical fibre amplifier have different gain bands, that is, C-band and L-band, thereby allowing the parallel optical fibre amplifier to operate in a very wide wavelength band while exhibiting a high power conversion efficiency.
In a particular embodiment, disclosed is a technique for providing an optical fibre amplifier having a configuration in which a C-band silica-based erbium-doped fibre amplifier (EDFA) stage and an L-band EDFA stage are coupled together in parallel in such a fashion that a reverse amplified spontaneous emission (ASE) light emitted from the C-band and/or L-band EDFA stage is re-used as a secondary pumping source for amplification in the L-band
EDFA stage.
In a preferred optical fibre amplifier of the invention, reverse ASE light emitted from the C-band EDFA stage and reverse ASE light emitted from the L-band EDFA stages are inserted into the L-band EDFA stage so that they are reused in the L-band EDFA stage. After testing the performance of an optical fibre amplifier according to the present invention, it could be found that when a pumping operation is conducted using light having a wavelength of 980 nm, a remarkable increase in the power conversion efficiency of the entire system is exhibited. Better performances in terms of the noise factor was also exhibited. Thus, an optical fibre amplifier having a greatly improved performance can be provided in accordance with the present invention.
While this invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiment, but, on the contrary, it is intended to cover various modifications within the spirit and scope of the appended claims.
Claims (11)
- CLAIMS: 1. A parallel optical fibre amplifier comprising a first erbium-doped fibre amplifier (EDFA) stage, and a second EDFA stage connected to the first EDFA stage in parallel, further comprising: means for re-using spontaneous emission light emitted from the first EDFA stage as a secondary pumping source for the second EDFA stage.
- 2. A parallel optical fibre amplifier according to claim 1, the second EDFA stage having a gain wavelength band different from that of the first EDFA stage,
- 3. A parallel optical fibre amplifier in accordance with claim 2, wherein the first EDFA stage comprises a C band EDFA, and the second EDFA stage comprises an L band EDFA and/or vice versa.
- 4. A parallel optical fibre amplifier in accordance with any of claims 1 to 3 wherein the re-using means comprises : a circulator for receiving the spontaneous emission light from the first EDFA stage; a connecting optical fibre for transmitting the received spontaneous emission light to the second EDFA stage; and an optical coupler connected between the connecting optical fibre and the second EDFA stage in such a fashion that the spontaneous emission light from the connecting optical fibre is transmitted to the second EDFA stage.
- 5. A parallel optical fibre amplifier in accordance with any of claims lto 4, wherein: the second EDFA stage comprises optical pumping means, a first optical fibre portion adapted to be optically pumped by the optical pumping means, and a second optical fibre portion adapted not to be pumped by the optical pumping means.
- 6. A parallel optical fibre amplifier according to claim 5, in which the means for re-using spontaneous emission light emitted from the first EDFA stage is arranged to pump the second optical fibre portion of the second EDFA.
- 7. A parallel optical fibre amplifier according to claim 5 or 6, in which the optical pumping means of the second EDFA stage is arranged between the first and second optical fibre portions and conducts a forward pumping operation for the first optical fibre portion.
- 8. A parallel optical fibre amplifier according to claim 5,6 or 7 in which reverse spontaneous emission light from the first optical fibre portion is re-used as a pumping source for the second optical fibre portion.
- 9. A parallel optical fibre amplifier in accordance with any one of claims 1 to 8, wherein the first and/or second EDFA stages each comprise one or more silica based optical fibre (s).
- 10. A parallel optical fibre amplifier comprising a first erbium doped fibre amplifier (EDFA) stage, and a second EDFA stage connected to the first EDFA stage in parallel, wherein the second EDFA stage comprises optical pumping means, a first optical fibre portion adapted to be optically pumpted by the optical pumping means, and a second optical fibre portion adapted not to be pumped by the optical pumping means, in which spontaneous emission light from the first optical fibre portion is re-used as a pumping source for the second optical fibre portion.
- 11. A parallel optical fibre amplifier substantially as described herein with reference to the figures.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1019980050479A KR20000033570A (en) | 1998-11-24 | 1998-11-24 | Connection terminal of terminal block and mounting structure of the same |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9927613D0 GB9927613D0 (en) | 2000-01-19 |
| GB2344210A true GB2344210A (en) | 2000-05-31 |
| GB2344210B GB2344210B (en) | 2001-04-04 |
Family
ID=19559515
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9927613A Expired - Fee Related GB2344210B (en) | 1998-11-24 | 1999-11-23 | Parallel optical fibre amplifier |
Country Status (2)
| Country | Link |
|---|---|
| KR (1) | KR20000033570A (en) |
| GB (1) | GB2344210B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2363675A (en) * | 2000-01-19 | 2002-01-02 | Advantest Corp | Wideband optical amplifier and wideband optical source |
| US7061667B2 (en) | 2002-04-08 | 2006-06-13 | Marconi Uk Intellectual Property Ltd. | Optical amplifiers |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116960714B (en) * | 2023-09-20 | 2024-01-30 | 武汉长进光子技术股份有限公司 | Optical fiber amplifier |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5117196A (en) * | 1989-04-22 | 1992-05-26 | Stc Plc | Optical amplifier gain control |
| US5604627A (en) * | 1995-05-18 | 1997-02-18 | Robert Bosch Gmbh | Optical amplifier device |
-
1998
- 1998-11-24 KR KR1019980050479A patent/KR20000033570A/en not_active Application Discontinuation
-
1999
- 1999-11-23 GB GB9927613A patent/GB2344210B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5117196A (en) * | 1989-04-22 | 1992-05-26 | Stc Plc | Optical amplifier gain control |
| US5604627A (en) * | 1995-05-18 | 1997-02-18 | Robert Bosch Gmbh | Optical amplifier device |
Non-Patent Citations (1)
| Title |
|---|
| OSA TECH.SERIES VOL6,1997,"ULTRA-BROADBAND & GAIN FLATTENED EDFAS FOR WDM SIGNALS" A. MORI PP371-374 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2363675A (en) * | 2000-01-19 | 2002-01-02 | Advantest Corp | Wideband optical amplifier and wideband optical source |
| GB2363675B (en) * | 2000-01-19 | 2004-05-26 | Advantest Corp | Wideband optical amplifier and wideband variable wavelength optical source |
| US7061667B2 (en) | 2002-04-08 | 2006-06-13 | Marconi Uk Intellectual Property Ltd. | Optical amplifiers |
Also Published As
| Publication number | Publication date |
|---|---|
| KR20000033570A (en) | 2000-06-15 |
| GB2344210B (en) | 2001-04-04 |
| GB9927613D0 (en) | 2000-01-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20061123 |