WO2001011735A1 - Amplificateur optique - Google Patents

Amplificateur optique Download PDF

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Publication number
WO2001011735A1
WO2001011735A1 PCT/JP2000/005233 JP0005233W WO0111735A1 WO 2001011735 A1 WO2001011735 A1 WO 2001011735A1 JP 0005233 W JP0005233 W JP 0005233W WO 0111735 A1 WO0111735 A1 WO 0111735A1
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WO
WIPO (PCT)
Prior art keywords
amplification
optical fiber
signal light
gain
band
Prior art date
Application number
PCT/JP2000/005233
Other languages
English (en)
Japanese (ja)
Inventor
Hisashi Sawada
Minoru Yoshida
Kazuo Imamura
Original Assignee
Mitsubishi Cable Industries, Ltd.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Mitsubishi Cable Industries, Ltd. filed Critical Mitsubishi Cable Industries, Ltd.
Publication of WO2001011735A1 publication Critical patent/WO2001011735A1/fr

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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
    • H01S3/06758—Tandem 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
    • H01S3/05—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
    • H01S3/06708—Constructional details of the fibre, e.g. compositions, cross-section, shape or tapering
    • H01S3/06716—Fibre compositions or doping with active elements

Definitions

  • the present invention relates to an optical amplifier provided with an amplifying optical fiber for directly amplifying signal light by the stimulated emission effect as an amplifying element, and particularly to a technique for smoothly performing amplification in wavelength division multiplex communication.
  • an optical amplifier is used to amplify the power of signal light attenuated in the middle of a transmission line and send the amplified signal light to the optical transmission line again.
  • amplification doped with A1 together with Er Optical fibers are effective because the amplification gain wavelength band has a relatively wide range (1531 ⁇ ! ⁇ 156 nm) centered at 150 nm. Academic Fall Meeting (see 199 2) C-263.
  • wavelength-division multiplexing communication especially when using a dispersion-shifted fiber (DSF) in which the zero dispersion is shifted to the 1550 nm band as a silica-based optical fiber for transmission, so-called light wave mixing is used.
  • DSF dispersion-shifted fiber
  • Light of an unnecessary wavelength component is generated, which becomes noise and signal degradation easily occurs. Therefore, in wavelength division multiplexing communication, 157 ⁇ !, which is slightly longer than the 1550 nm band!
  • L-band a wavelength range of up to 16 1 O nm
  • L-band has been studied to suppress the degradation of transmission characteristics due to light wave mixing as described above. Therefore, in order to amplify a signal whose wavelength range is multiplexed, it is necessary to extend the amplifiable range of the amplification optical fiber to the L-band.
  • wavelength gain difference A large gain is obtained in the wavelength band including L-band, • have gain characteristics that are flattened in the wavelength band including the L band so that no gain difference (hereinafter, referred to as wavelength gain difference) occurs in the amplification output of each signal light;
  • the present invention has been made to solve the above problems, and when performing amplification in the L-band, a large gain is obtained for each signal light included in the L-band, and The purpose is to reduce the wavelength gain difference of each signal light.
  • a front-stage amplifier and a rear-stage amplifier are connected in cascade, and each of the front-stage and rear-stage amplifiers includes an amplification optical fiber as an amplification element for amplifying signal light by the stimulated emission effect.
  • the product of the concentration length which is the product of the doping amount of Er and the length of the optical fiber for amplification of the preamplifier, is 4 to 8 kppm ⁇ m.
  • the concentration length product of the amplification optical fiber of the post-amplification section is set to 80 to 10 Oppm ⁇ m. Thereby, the wavelength gain difference of each signal light can be reduced.
  • the preamplifier and the postamplifier are connected via an isolator, and the preamplifier and the postamplifier are each provided with the amplifying optical fiber. It is preferable to provide an excitation light source for bombing.
  • FIG. 1 is a configuration diagram of an optical amplifier according to an embodiment of the present invention.
  • FIG. 2 is a diagram showing experimental results obtained by examining gain characteristics using the optical amplifier having the configuration of FIG.
  • FIG. 3 is a diagram showing an experimental result obtained by examining a gain characteristic using the optical amplifier having the configuration of FIG. BEST MODE FOR CARRYING OUT THE INVENTION
  • FIG. 1 is a diagram illustrating an overall configuration of an optical amplifier according to an embodiment of the present invention.
  • the optical amplifier 1 of this embodiment has a two-stage amplification configuration. That is, the optical amplifier 1 has a front-stage amplifier 2a and a rear-stage amplifier 2b, and the front and rear amplifiers 2a and 2b are connected to each other via the isolator 4.
  • the preamplifier 2a includes an amplification optical fiber 6a as an amplification element for amplifying signal light by the stimulated emission effect, an excitation light source 7a such as a laser diode for pumping the amplification optical fiber 6a, and An optical power bra 8a for introducing the excitation light from the excitation light source 7a to the amplification optical fiber 6a is provided.
  • the preamplifier 2a is of a forward pump type in which the signal light and the pump light enter the amplification optical fiber 6a from the same direction.
  • the post-amplifying unit 2b includes an amplification optical fiber 6b as an amplification element for amplifying signal light by the stimulated emission effect, an excitation light source 7b such as a laser diode for pumping the amplification optical fiber 6b, and an excitation light source 7b.
  • An optical power bra 8b for introducing the excitation light from the light source 7b into the amplification optical fiber 6b.
  • the post-amplifier 2b is of a post-pump type in which pump light is incident on the amplification optical fiber 6b from the opposite direction with respect to the signal light.
  • Er and A1 are co-doped in the core or in the outer periphery thereof.
  • the amplification optical fiber 6b is set so that the concentration length product, which is the product of the Dop amount of Er in the optical fiber 6b and the length of the optical fiber 6b, is 80 to 10 Oppm ppm. It has been done.
  • the pump light sources 7 that bomb both optical fibers 6a and 6b are used.
  • Appropriate conditions for the pump light powers of a and 7b are also different from each other. For this reason, there is a concern that the excitation light and the fluorescence from the excitation light source 7b of the rear amplification unit 2b may affect the front amplification unit 2a.
  • the isolator 4 is provided between the two amplifying sections 2a and 2b, the excitation light and the fluorescent light from the excitation light source 7b of the subsequent amplifying section 2b are not separated by the isolator 4.
  • the pump light of the former-stage amplifier 2a passes through the isolator 4 and enters, so that the power of the pump light source 7b of the latter-stage optical fiber 6b is changed from the former-stage amplifier 2a.
  • the setting may be made in consideration of the power of the exciting pump light.
  • 10a and 1 Ob are polarization-independent isolators that pass signal light only in one direction to suppress parasitic oscillation and reduce noise
  • 12a and 12b are input / output connectors.
  • Numeral 14 denotes a coupling optical fiber for coupling these elements.
  • the gain wavelength for the front and rear wavelength bands including the L-band is determined. The results of examining the characteristics are shown below.
  • the Er doping amount of 90 0 ⁇ A1 is 10000 ppm
  • the power-off wavelength is 0.92 ⁇
  • the mode field diameter is 4.5 m.
  • the concentration length product CL1 is set to 4 kppm'm, 6 kppm ⁇ m, and 8 kppm ⁇ m, respectively.
  • the pumping light wavelength of the preamplifier 2a is set to 1.48 / m
  • the pumping light power is set to 5 OmW.
  • the amplification optical fiber 6b in the rear amplification section 2b has the same characteristics as the amplification optical fiber 6a in the front amplification section 2a. However, the length of the optical fiber 6b is lengthened, and the concentration length product CL 2 is fixedly set to 4 Okppm ⁇ m. Also, the pumping light wavelength of the post-amplifier 2 b is set to 1.48 And the pump light power is 15 OmW.
  • the concentration-length product CL1 of the amplification optical fiber 6a in the preamplifier 2a in Fig. 1 was set to 4 kppmm, 6 kppm-m, and 8 kppmm.
  • the band where the gain is larger spreads to the longer wavelength side.t
  • the concentration-length product CL 1 is increased, the rising part of the characteristic curve is slightly shifted to the longer wavelength side.
  • the maximum gain is almost unchanged regardless of the signal light input of 1 OdBm, -40 dBm, regardless of the concentration length product CL1.
  • the portion where the gain is flat is in the range of 1550 to 158 Onm, and the gain in that case is about 3 ldB.
  • the maximum gain does not change even if CL 1 is changed even if the concentration length product CL 1 of the amplification optical fiber 6 a in the pre-amplification section 2 a is changed by the concentration length product of the amplification optical fiber 6 b in the post-amplification section 2 b.
  • the reason is that because the CL 2 is large and has a sufficient amplification factor, the amplification effect of the amplification optical fiber 6a in the pre-amplification section 2a does not appear significantly to the gain. Conceivable.
  • Table 1 shows the wavelength band where the amount of decrease in the gain from its maximum value is less than 1 dB when the signal light input is -1 OdBm.
  • the wavelength band in this case is approximately 28 nm when the concentration-length product CL 1 of the amplification optical fiber 6 a is 4 kppmm, 6 kppm-m, or 8 kppnim.
  • Table 2 shows the wavelength band where the gain is 30 dB or more when the signal light input is 11 OdBm. As shown in Table 2, the wavelength band in this case is approximately equal when the concentration-length product CL1 of the amplification optical fiber 6a is 4 kppmm, 6 kppm-m, or 8 kppmm. It has a width of 32 nm.
  • the concentration-length product CL 2 of the amplification optical fiber 6 b in the post-amplifying section 2 b is set to 4 Okppm ⁇ m
  • the gain is L—band (1570 M! ⁇ 16 1 Onm) It is hard to say that it is flat throughout. Therefore, it can be understood that the above conditions alone are not enough to obtain sufficient gain flatness for the L-band.
  • the doping amount of Er is 900 Opm
  • the doping amount of A1 is 100 Oppm
  • the cut-off wavelength is 0.92 ⁇ mode field diameter 4.5. It has the features of 1 and uses the product of concentration length product CL 1 of 8 kppm ⁇ m.
  • the pump light wavelength of the preamplifier 2a is 1.48 // m, and the pump light power is 5 OmW.
  • the amplification optical fiber 6b in the rear amplification unit 2b has the same characteristics as the amplification optical fiber 6b in the front amplification unit 2a. However, for the optical fiber 6b, use four types of optical fiber 6b whose length is made longer and the concentration length product CL2 is 4 Okppmm, 80 kppm-m, 90 kppm-m, 10 Okppm-m. ing. Also, the pump light of the post-amplifier 2b The wavelength is 1.48 zm and the pump light power is 15 OmW.
  • the concentration length product CL 2 of the amplification optical fiber 6 b in the post-amplifier 2 b is set to 40 kppm-m, the signal light wavelength exceeds 158 58 ⁇ .
  • the gain of the characteristic curve gradually decreases, which is insufficient for flattening the gain over the entire L-band (1570 nm to 1610M).
  • the signal light input is -1 OdBm
  • the concentration length product CL 2 of the amplification optical fiber 6b is 8 Okppm ⁇ ⁇ !
  • the gain is flat over the entire L-band, and the gain in that case is about 3 I dB.
  • Table 3 shows the wavelength band where the amount of decrease in the gain from its maximum value is less than 1 dB when the signal light input is 11 OdBm.
  • the wavelength band in this case is as follows:
  • the concentration-length product CL2 of the optical fiber 6b for amplification is 8 Okppm ⁇ m, 90 kppm-in, and 100 kppm ⁇ m. It has a width of about 46 nm including the band.
  • Table 4 shows the wavelength band where the gain is 30 dB or more when the signal light input is 11 OdBm.
  • the wavelength band in this case is either when the concentration length product CL2 of the optical fiber for amplification 6b is 80 kppm ⁇ m, 90 kppm-m, or 100 kppm ⁇ m. Also has a width of about 48 nm including the L-band.
  • Table 5 shows the wavelength band where the gain is 30 dB or more when the signal light input is 4 OdBm. As shown in Table 5, in this case, the concentration band product of the optical fiber for amplification 6b, CL2, is 8 Okppm ⁇ m, 90 kppm-m, and 100 kppm-m. —It has a width of about 56 nm including the band.
  • the conversion efficiency from pump light to signal light in a wavelength band in which the amount by which the gain decreased from the maximum value was less than 1 dB was examined. It was 50-60%. Although this conversion efficiency does not reach the conversion efficiency of 74% in the case of the conventional example, it is a practically sufficient value.
  • the concentration length product CL of the amplification optical fiber 6a in the front amplification unit 2a is set to 8 kppmm
  • the concentration length product CL of the amplification optical fiber 6b in the rear amplification unit 2b is set to 8 kppmm
  • the concentration length product CL of the amplification optical fiber 6b in the rear amplification unit 2b is set to 8 kppmm
  • gain flattening over the entire L-band 570-161 Onm
  • the concentration-length product CL 2 was set to 80 to 10 Okppm ⁇ m, the gain over the entire L-band could be sufficiently flattened.
  • the concentration-length product CL1 of the amplification optical fiber 6a in the preamplifier 2a was fixed at 8 kppmm, and CL1 was set to 4 kppmm or 6 kppmm and CL2 was set to 6 kppmm. Were not changed to 8 Okppm ⁇ m, 90 kppm-in, 100 kppm ⁇ m.
  • the flattening of the gain requires more than the influence of the concentration-length product CL1 of the amplification optical fiber 6a in the pre-amplification section 2a, rather than the influence of the amplification optical fiber 6b in the post-amplification section 2b.
  • the CL 1 force is 8 kppm ⁇ m even if (: 1 is set to 41 ⁇ 111 '111 ⁇ It is considered that a curve having a gain characteristic similar to that of is obtained.
  • the preamplifier 2a is a forward pump type
  • the rear amplifier 2b is a backward pump type.
  • the present invention is not limited to this. It is also possible to use an excitation type, the rear amplification unit 2b is a forward excitation type, or both the front and rear amplification units 2a and 2b are both a forward excitation type, or both are a backward excitation type.
  • the present invention when amplification is performed in the L-band (l 570 nn! To 1610 nm), a large gain can be obtained for the signal light of each wavelength included in the L-band. Further, the wavelength gain difference of the signal light can be reduced.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Optics & Photonics (AREA)
  • Lasers (AREA)
  • Light Guides In General And Applications Therefor (AREA)
  • Optical Communication System (AREA)

Abstract

L'invention concerne un amplificateur optique qui comprend : un élément amplificateur comportant un amplificateur à fibres optiques qui amplifie directement la lumière de signal par émission stimulée. En vue de l'amplification dans la bande L (entre 1570nm et 1610nm), un gain étendu est obtenu pour toute la lumière de signal située dans la bande L, alors que la différence de gain entre les longueurs d'onde de la lumière de signal est réduite. L'amplificateur optique est composé d'un étage frontal (2a) et d'un étage final (2b), qui comportent des amplificateurs à fibres optiques (6a, 6b) permettant d'amplifier la lumière de signal par émission stimulée. Le produit de la dose Er et de la longueur de fibre varie entre 4 et 8 kppm-m pour l'amplificateur à fibres optiques (6a) situé dans l'étage frontal (2a), et entre 80 et 100 kppm-m pour l'amplificateur à fibres optiques (6b) situé dans l'étage final (26).
PCT/JP2000/005233 1999-08-04 2000-08-03 Amplificateur optique WO2001011735A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP11/220982 1999-08-04
JP22098299A JP3787045B2 (ja) 1999-08-04 1999-08-04 光増幅器

Publications (1)

Publication Number Publication Date
WO2001011735A1 true WO2001011735A1 (fr) 2001-02-15

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Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4281245B2 (ja) * 2000-12-15 2009-06-17 富士通株式会社 光増幅器
JP2003092449A (ja) * 2001-09-17 2003-03-28 Fujikura Ltd 光ファイバ増幅器
JP2007288124A (ja) * 2006-03-22 2007-11-01 Nippon Telegr & Teleph Corp <Ntt> 光ファイバ増幅器

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06224511A (ja) * 1993-01-27 1994-08-12 Mitsubishi Cable Ind Ltd 増幅用光ファイバ
EP0803944A2 (fr) * 1996-04-22 1997-10-29 Lucent Technologies Inc. Article comprenant un amplificateur hybride à plusieurs étages à fibre optique
US5920424A (en) * 1997-02-18 1999-07-06 Lucent Technologies Inc. Article comprising a broadband optical fiber amplifier
JPH11307851A (ja) * 1998-04-24 1999-11-05 Nippon Telegr & Teleph Corp <Ntt> 光ファイバ増幅器

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06224511A (ja) * 1993-01-27 1994-08-12 Mitsubishi Cable Ind Ltd 増幅用光ファイバ
EP0803944A2 (fr) * 1996-04-22 1997-10-29 Lucent Technologies Inc. Article comprenant un amplificateur hybride à plusieurs étages à fibre optique
US5920424A (en) * 1997-02-18 1999-07-06 Lucent Technologies Inc. Article comprising a broadband optical fiber amplifier
JPH11307851A (ja) * 1998-04-24 1999-11-05 Nippon Telegr & Teleph Corp <Ntt> 光ファイバ増幅器

Non-Patent Citations (7)

* Cited by examiner, † Cited by third party
Title
ELECTRONICS LETTERS, vol. 28, no. 20, 24 September 1992 (1992-09-24), pages 1924 - 1925, XP002933190 *
ELECTRONICS LETTERS, vol. 33, no. 8, 10 April 1997 (1997-04-10), pages 710 - 711, XP002933188 *
ELECTRONICS LETTERS, vol. 34, no. 15, 23 July 1998 (1998-07-23), pages 1490 - 1491, XP002933184 *
ELECTRONICS LETTERS, vol. 34, no. 18, 3 September 1998 (1998-09-03), pages 1747 - 1748, XP002933185 *
IEEE PHOTONICS TECHNOLOGY LETTERS, vol. 10, no. 9, September 1998 (1998-09-01), pages 1244 - 1246, XP002933187 *
IEEE PHOTONICS TECHNOLOGY LETTERS, vol. 9, no. 5, May 1997 (1997-05-01), pages 596 - 598, XP002933189 *
IEEE PHOTONICS TECHNOLOGY, vol. 8, no. 5, May 1996 (1996-05-01), pages 620 - 622, XP002933186 *

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JP2001044551A (ja) 2001-02-16
JP3787045B2 (ja) 2006-06-21

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