GB2377814A - Optical amplifier with tunable pump laser - Google Patents

Optical amplifier with tunable pump laser Download PDF

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Publication number
GB2377814A
GB2377814A GB0106769A GB0106769A GB2377814A GB 2377814 A GB2377814 A GB 2377814A GB 0106769 A GB0106769 A GB 0106769A GB 0106769 A GB0106769 A GB 0106769A GB 2377814 A GB2377814 A GB 2377814A
Authority
GB
United Kingdom
Prior art keywords
laser
pump laser
pump
optical
amplifier
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.)
Withdrawn
Application number
GB0106769A
Other versions
GB0106769D0 (en
Inventor
Lloyd Langley
Stephen Taylor
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Lumentum Technology UK Ltd
Teledyne UK Ltd
Original Assignee
Bookham Technology PLC
Marconi Applied Technologies 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 Bookham Technology PLC, Marconi Applied Technologies Ltd filed Critical Bookham Technology PLC
Priority to GB0106769A priority Critical patent/GB2377814A/en
Publication of GB0106769D0 publication Critical patent/GB0106769D0/en
Priority to PCT/GB2002/001301 priority patent/WO2002075976A1/en
Publication of GB2377814A publication Critical patent/GB2377814A/en
Withdrawn legal-status Critical Current

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Classifications

    • 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

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Lasers (AREA)

Abstract

The optical amplifier includes a tunable pump laser, <B>5</B>, adapted to pump an optical fibre in an optical circuit via a coupler, <B>3</B>. The fibre amplifier, <B>4</B>, is preferably doped with erbium and the pump laser may be a tunable III-V semiconductor laser. Gratings can be used to tune the pump laser, the preferred type being a segmented grating DBR.

Description

23778 1 4
Optical Amplifier The present invention relates to an optical amplifier, in particular an erblum doped fibre amplifier (EDFA), having control means to compensate for non optimum performance.
In an optical amplifier, such as an EDFA, for a given pump power, to obtain the maximum amount of gain for a given erbium concentration in the fibre core, the fibre length should be increased to the point at which the pump power becomes equal to the intrinsic pump threshold. This determines the optimum length of the fbre to maximise the signal gain for the amplifier. However, for other applications, the fibre length may need to be optimised for other parameters such as the noise figure or output saturation power. For a number of reasons, when an optical amplifier has been assembled, the fibre length may prove to be sub-optimal. It is known to compensate for sub-optimal performance of an optical amplifier by increasing the pump power. It is also known to tailor the gain of a WDM amplifier by an appropriate choice of the fibre length.
However, the known approaches suffer from the problem that the pump laser is often working near its maximum power for performance reasons and it is also clearly not ideal to have to re-splice optical fibre more than is necessary.
The present invention seeks to provide an optical amplifier with control means which control means is adapted to modify the gain in situ.
According to the invention, there is provided an optical amplifier having a pump laser, which pump laser is adapted to pump an optical fibre in an optical circuit via an opto-
coupler, wherein the pump laser is a tuneable laser.
Preferably, the amplifier is an erbium doped fibre amplifier. Preferably the pump laser is a m-v semiconductor tuneable laser.
This has the advantage that the length of fibre is no longer critical to the optimum performance and the amplifier performance can be compensated for by tuning the pump laser. The ability to tune the wavelength of the pump laser allows the laser wavelength to be matched to the assembled components. This is particularly advantageous as it is simpler to tune the laser than to change the length of fibre in the amplifier once the amplifier has been assembled.
An exemplary embodiment of the invention will now be described in greater detail with reference to the drawings, in which: Fig. 1 shows a schematic representation of an EDFA The amplifier is connected between an optical fibre input line 1 and an output line 2, the fibres being formed of a silica core of 7nm diameter surrounded by an outer sleeve of silica having a different refractive index of approximately 120nm. The amplifier is intended for the transmission of optical signals at a frequency of approximately 1530nm to form a telecommunication transmission signal. The input line 1 is optically connected to a dichroic coupler 3, which, in turn, is connected to the output line 2 via a fibre coil 4.
The fibre coil 4 is doped with erbium which, when excited by an applied signal at the right frequency, is amplified. A tuneable laser 5 is connected optically to the dichroic coupler 3 so that when an electrical signal is applied to the laser 5, a light signalis transmitted to the fibre coil 4 through the dichroic coupler 3. The erblum ions in the erbium doped optical fibre coil 4 are inverted by the pumped signal to generate a signal gam. The pump laser 5 is a wavelength tuneable laser having sampled gratings at the front and rear of its gain region. The gratings produce slightly different reflection combs which provide feedback into the device. The gratings can be current tuned in wavelength with respect to each other. Co-incidence of a maximum from each of the front and rear gratings is referred to as a supermode. To switch the device between super modes requires a small electrical current into one of the gratings to cause a different pair of maxima to co-incide in the manner of a vernier. By applying different electrical currents to the two gratings, continuous tuning within a supermode can be achieved.
The use of a tuneable laser as a pump laser enables the pump laser to also fulfil a function as a control means not simply for power. This enables the wavelength of the pump laser to be matched to the assembled components in the EDFA to optimise performance rather than having to re- splice the fibre with the concomitant risks of fibre damage and further deterioration in amplifier performance.
Although the laser 5 has been described as a Segmented Grating-DBR, it would be possible to use other types of tuneable laser such as a Phase Shift Grating Distributed Bragg Reflector laser. It would also be possible to use non current driven tuneable lasers in appropriate circumstances.

Claims (5)

Claims
1. An optical amplifier having a pump laser, which pump laser is adapted to pump an optical fibre in an optical circuit via a coupler, wherein the pump laser is a tuneable laser.
2. An optical amplifier according to Claim 1, wherein the amplifier is an erbium doped fibre amplifier
3. An optical amplifier according to Claim 1 or Claim 2, wherein the pump laser is a m-v semiconductor tuneable laser.
4. An optical amplifier according to any one of Claims 1 to 3, wherein the pump laser is a segmented grating distributed Bragg reflector laser.
5. An optical amplifier substantially as described herein, with reference to and as illustrated in the accompanying drawing.
GB0106769A 2001-03-19 2001-03-19 Optical amplifier with tunable pump laser Withdrawn GB2377814A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB0106769A GB2377814A (en) 2001-03-19 2001-03-19 Optical amplifier with tunable pump laser
PCT/GB2002/001301 WO2002075976A1 (en) 2001-03-19 2002-03-19 Erbium doped fibre amplifier having a tuneable pump laser

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB0106769A GB2377814A (en) 2001-03-19 2001-03-19 Optical amplifier with tunable pump laser

Publications (2)

Publication Number Publication Date
GB0106769D0 GB0106769D0 (en) 2001-05-09
GB2377814A true GB2377814A (en) 2003-01-22

Family

ID=9911012

Family Applications (1)

Application Number Title Priority Date Filing Date
GB0106769A Withdrawn GB2377814A (en) 2001-03-19 2001-03-19 Optical amplifier with tunable pump laser

Country Status (2)

Country Link
GB (1) GB2377814A (en)
WO (1) WO2002075976A1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1848073A1 (en) 2006-04-19 2007-10-24 Multitel ASBL Switchable laser device and method for operating said device

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5539571A (en) * 1992-09-21 1996-07-23 Sdl, Inc. Differentially pumped optical amplifer and mopa device
US5912910A (en) * 1996-05-17 1999-06-15 Sdl, Inc. High power pumped mid-IR wavelength systems using nonlinear frequency mixing (NFM) devices
US6144486A (en) * 1998-01-30 2000-11-07 Corning Incorporated Pump wavelength tuning of optical amplifiers and use of same in wavelength division multiplexed systems
US6178036B1 (en) * 1997-01-14 2001-01-23 California Institute Of Technology Opto-electronic devices and systems based on brillouin selective sideband amplification
WO2001016642A2 (en) * 1999-09-02 2001-03-08 Agility Communications, Inc. Integrated opto-electronic wavelength converter assembly

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5574589A (en) * 1995-01-09 1996-11-12 Lucent Technologies Inc. Self-amplified networks
US6509987B1 (en) * 1999-08-10 2003-01-21 Lucent Technologies Channel band conversion apparatus for optical transmission systems

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5539571A (en) * 1992-09-21 1996-07-23 Sdl, Inc. Differentially pumped optical amplifer and mopa device
US5912910A (en) * 1996-05-17 1999-06-15 Sdl, Inc. High power pumped mid-IR wavelength systems using nonlinear frequency mixing (NFM) devices
US6178036B1 (en) * 1997-01-14 2001-01-23 California Institute Of Technology Opto-electronic devices and systems based on brillouin selective sideband amplification
US6144486A (en) * 1998-01-30 2000-11-07 Corning Incorporated Pump wavelength tuning of optical amplifiers and use of same in wavelength division multiplexed systems
WO2001016642A2 (en) * 1999-09-02 2001-03-08 Agility Communications, Inc. Integrated opto-electronic wavelength converter assembly

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Advanced Semiconductor Lasers at Marconi Materials Technology, Caswell, GEC Review, Vol.14, No. 2, 1999 *

Also Published As

Publication number Publication date
GB0106769D0 (en) 2001-05-09
WO2002075976A1 (en) 2002-09-26

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WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)