CA2318675A1 - Tunable optical fiber light source - Google Patents
Tunable optical fiber light source Download PDFInfo
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- CA2318675A1 CA2318675A1 CA 2318675 CA2318675A CA2318675A1 CA 2318675 A1 CA2318675 A1 CA 2318675A1 CA 2318675 CA2318675 CA 2318675 CA 2318675 A CA2318675 A CA 2318675A CA 2318675 A1 CA2318675 A1 CA 2318675A1
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- fiber
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- 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
- H01S3/0675—Resonators including a grating structure, e.g. distributed Bragg reflectors [DBR] or distributed feedback [DFB] fibre lasers
-
- 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
- H01S3/005—Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping
- H01S3/0064—Anti-reflection devices, e.g. optical isolaters
-
- 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
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
- H01S3/10007—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating in optical amplifiers
- H01S3/10023—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating in optical amplifiers by functional association of additional optical elements, e.g. filters, gratings, reflectors
- H01S3/1003—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating in optical amplifiers by functional association of additional optical elements, e.g. filters, gratings, reflectors tunable optical elements, e.g. acousto-optic filters, tunable gratings
-
- 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
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
- H01S3/10084—Frequency control by seeding
-
- 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
- H01S3/30—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range using scattering effects, e.g. stimulated Brillouin or Raman effects
- H01S3/302—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range using scattering effects, e.g. stimulated Brillouin or Raman effects in an optical fibre
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- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Optics & Photonics (AREA)
- Lasers (AREA)
Description
Patent name: Tunable light source Background:
UV light can induce a permanent refractive index change in some kind optical fibers and optical wave-guides. The photosensitivity of the certain kind optical fiber waveguide can be used to make Bragg grating and long period gratings, which is a permanent, spatially periodic refractive index modulation along the length of the photosensitive core of the optical fiber or optic wave guide. Fiber Bragg gratings can selectively reflect specific wavelengths of light within an optical fiber. The selective reflected wavelength is equal to the twice the periods of the Bragg grating times the effective refractive index of the propagation mode. Fiber grating have many applications including band rejection filter, semiconductor laser stabilizer, fiber laser wavelength selector, fiber amplifier reflector, fiber dispersion compensation, DWDM filter, WDM add and drop multiplex, light pulse shape reforming, optical fiber switch, optical sensor. '~'-'6' Tunable fiber grating uses a piezoelectric element to strain the grating '~'.
G.A.Ball and W.W.Morey used compression-tuned approach to tune fiber Bragg grating over 32 nm range 'g'. This approach needs very precisely grounded ceramic ferrules, and very high accurate alignment.
Dr. Pin Long used a new approach to tune fiber grating to 20nm wavelength range. '9' This new tunable fiber grating has many advantages like easy to operation, simple structure, and long working life time.
There is a demand to change the wavelength of the light source for optical fiber telecommunication applications. Tunable light source provides the telecommunications industry with an important tool for the design of new network architecture.
Tunable light source can provide wavelength-routing capabilities, network backup protection, or dedicated wavelengths for business customers. Tunable light source is also an important tool used at laboratory for testing fiber optical components. Tunable light source can be used in experimental setup for replacing many different wavelength lasers in WDM
testing. Mr. Chris F. Clarke and Jin Hong from Nortel Networks have successfully make l5nm tuning range distributed feedback (DFB) lasers. But this kind tunable laser is difficult to fabricate. Another type of laser is a external-cavity laser with 80nm tuning range. But it must work in a stable environment, and sensitive to mechanical shock and movement.
Accordingly, there is a need for a tunable light source with wide tuning range, having simple tuning mechanism and low cost.
Invention In the present invention, a tunable light source comprises a tunable fiber grating, a wide band light source and a gain medium. The wide band light source and the gain medium can be a one unit or two separate units. The wide band light source is used as a wide band light signal input. The tunable fiber grating is used to select a wavelength signal from the wide bandwidth light source. And the gain medium amplifies the selected wavelength signal. To select a certain bandwidth from a wide band light source is called spectrum slicing by some people's°'-'~2'. The selected wavelength, after amplified, is as output light signal. The wavelength of the narrow band light source can be changed by changing tunable fiber grating wavelength. The output light signal is a narrow bandwidth, high power light source. Because the tunable fiber grating can tune the reflection light wavelength in a wide range, the output light wavelength will have a wide tuning range change. A tunable wide band light source is made with this device.
The wide band light source can be light emitting diode (LED) including surface light emitting diode (SLED) and edge light emitting diode (ELED). The wide band light source can also be amplified spontaneous emission (ASE) source from an Erbium doped fiber amplifier (EDFA). The wide band light source can also be ASE source from Raman amplifier. The wide band light source can also be ASE source from a semiconductor amplifier. The wide band light source can also be ASE source signal from other fiber amplifiers. 'The wide band light source can also be light signal from a white light source, like halogen lamp, mercury lamp, and deuterium lamp.
The gain medium can be Erbium doped fiber amplifier (EDFA), Raman amplifier, semiconductor amplifier, waveguide amplifier, or other fiber amplifiers.
The optical fiber in gain medium can also be erbium doped fiber, Ytterbium doped fiber and other kind doped fiber for example, Thulium doped fiber, Praseodymium doped fiber and Neodymium doped fiber. The fiber in gain medium can be simple mode fiber, multi mode fiber, double cladding single mode fiber, double cladding polarization maintain single mode fiber, double cladding multi mode fiber, double cladding polarization maintain mufti mode fiber. The optical fiber can be silica fiber, telluride fiber, fluoride fiber.
The tunable filter can be tunable fiber grating. The tunable fiber grating can be mechanical tuning fiber grating, temperature tuning fiber grating. The tunable fiber grating can also be magnatostrictive strain tuning.
The tunable filter can also be F-P inteferent filter.
To get the flat top narrow band signal output, the gain block can incorporated with a gain flattening filter. The output narrow band signal is uniform within a wide wavelength range.
The bandwidth o~ the output light signal can be variable from 0.01 nm to more than 100nm depending on the bandwidth of the tunable fiber grating. For some applications, different bandwidth light source is needed. Different bandwidth tunable fiber grating can be made to get different bandwidth tunable light source output. It is a big advantage of the wide range tunable light source with the tunable semiconductor laser, which has fixed ue bandwidth of output signal.
Brief Description of the drawings The advantages, nature and additional features of the invention will appear more fully upon consideration of the illustrative embodiments described in the accompanying drawings. In the drawings
UV light can induce a permanent refractive index change in some kind optical fibers and optical wave-guides. The photosensitivity of the certain kind optical fiber waveguide can be used to make Bragg grating and long period gratings, which is a permanent, spatially periodic refractive index modulation along the length of the photosensitive core of the optical fiber or optic wave guide. Fiber Bragg gratings can selectively reflect specific wavelengths of light within an optical fiber. The selective reflected wavelength is equal to the twice the periods of the Bragg grating times the effective refractive index of the propagation mode. Fiber grating have many applications including band rejection filter, semiconductor laser stabilizer, fiber laser wavelength selector, fiber amplifier reflector, fiber dispersion compensation, DWDM filter, WDM add and drop multiplex, light pulse shape reforming, optical fiber switch, optical sensor. '~'-'6' Tunable fiber grating uses a piezoelectric element to strain the grating '~'.
G.A.Ball and W.W.Morey used compression-tuned approach to tune fiber Bragg grating over 32 nm range 'g'. This approach needs very precisely grounded ceramic ferrules, and very high accurate alignment.
Dr. Pin Long used a new approach to tune fiber grating to 20nm wavelength range. '9' This new tunable fiber grating has many advantages like easy to operation, simple structure, and long working life time.
There is a demand to change the wavelength of the light source for optical fiber telecommunication applications. Tunable light source provides the telecommunications industry with an important tool for the design of new network architecture.
Tunable light source can provide wavelength-routing capabilities, network backup protection, or dedicated wavelengths for business customers. Tunable light source is also an important tool used at laboratory for testing fiber optical components. Tunable light source can be used in experimental setup for replacing many different wavelength lasers in WDM
testing. Mr. Chris F. Clarke and Jin Hong from Nortel Networks have successfully make l5nm tuning range distributed feedback (DFB) lasers. But this kind tunable laser is difficult to fabricate. Another type of laser is a external-cavity laser with 80nm tuning range. But it must work in a stable environment, and sensitive to mechanical shock and movement.
Accordingly, there is a need for a tunable light source with wide tuning range, having simple tuning mechanism and low cost.
Invention In the present invention, a tunable light source comprises a tunable fiber grating, a wide band light source and a gain medium. The wide band light source and the gain medium can be a one unit or two separate units. The wide band light source is used as a wide band light signal input. The tunable fiber grating is used to select a wavelength signal from the wide bandwidth light source. And the gain medium amplifies the selected wavelength signal. To select a certain bandwidth from a wide band light source is called spectrum slicing by some people's°'-'~2'. The selected wavelength, after amplified, is as output light signal. The wavelength of the narrow band light source can be changed by changing tunable fiber grating wavelength. The output light signal is a narrow bandwidth, high power light source. Because the tunable fiber grating can tune the reflection light wavelength in a wide range, the output light wavelength will have a wide tuning range change. A tunable wide band light source is made with this device.
The wide band light source can be light emitting diode (LED) including surface light emitting diode (SLED) and edge light emitting diode (ELED). The wide band light source can also be amplified spontaneous emission (ASE) source from an Erbium doped fiber amplifier (EDFA). The wide band light source can also be ASE source from Raman amplifier. The wide band light source can also be ASE source from a semiconductor amplifier. The wide band light source can also be ASE source signal from other fiber amplifiers. 'The wide band light source can also be light signal from a white light source, like halogen lamp, mercury lamp, and deuterium lamp.
The gain medium can be Erbium doped fiber amplifier (EDFA), Raman amplifier, semiconductor amplifier, waveguide amplifier, or other fiber amplifiers.
The optical fiber in gain medium can also be erbium doped fiber, Ytterbium doped fiber and other kind doped fiber for example, Thulium doped fiber, Praseodymium doped fiber and Neodymium doped fiber. The fiber in gain medium can be simple mode fiber, multi mode fiber, double cladding single mode fiber, double cladding polarization maintain single mode fiber, double cladding multi mode fiber, double cladding polarization maintain mufti mode fiber. The optical fiber can be silica fiber, telluride fiber, fluoride fiber.
The tunable filter can be tunable fiber grating. The tunable fiber grating can be mechanical tuning fiber grating, temperature tuning fiber grating. The tunable fiber grating can also be magnatostrictive strain tuning.
The tunable filter can also be F-P inteferent filter.
To get the flat top narrow band signal output, the gain block can incorporated with a gain flattening filter. The output narrow band signal is uniform within a wide wavelength range.
The bandwidth o~ the output light signal can be variable from 0.01 nm to more than 100nm depending on the bandwidth of the tunable fiber grating. For some applications, different bandwidth light source is needed. Different bandwidth tunable fiber grating can be made to get different bandwidth tunable light source output. It is a big advantage of the wide range tunable light source with the tunable semiconductor laser, which has fixed ue bandwidth of output signal.
Brief Description of the drawings The advantages, nature and additional features of the invention will appear more fully upon consideration of the illustrative embodiments described in the accompanying drawings. In the drawings
2.
Figure I schematically illustrates an embodiment of a tunable light source.
The 980nm pumping laser, WDM coupler and Erbium doped fiber are used as gain medium (or called amplified block). The ASE source coming from IJrbium doped fiber pumped by 980nm pumping laser is used as wide band light source. The tunable fiber grating can be mechanical tuning fiber grating, electrical tuning fiber grating or other kind tunable fiber grating.
Figure 2 schematically illustrates another embodiment of a tunable light source. The light emitting diode(LED) is used as a wide band light source. The circulator is used to put the narrow band light signal reflected from tunable fiber grating into the gain block. 980nm pumping laser, WDM coupler and Erbium doped fiber are used as gain medium. The tunable fiber grating can be mechanical tuning fiber grating, electrical tuning fiber grating or other kind tunable fiber grating.
Figure 3 schematically illustrates another embodiment of a tunable light source. The ASE
source coming from Erbium doped fiber pumped by 980nm pumping laser is used as wide band source. The 980nm pumping laser, WDM coupler and Erbium doped fiber is also used as gain medium at same time. The back transmitted ASE signal from the Erbium doped fiber is used as wide band light source. The tunable fiber grating can be mechanical tuning fiber grating, electrical tuning fiber grating or other kind tunable fiber grating.
Figure 4 schematically illustrates another embodiment of a tunable light source. The light emitting diode (L>vD) is used as a wide band light source. The circulator is used to put the narrow band light signal reflected from the tunable fiber grating into the gain medium (or amplified block) for being amplified. The semiconductor amplifier is used as gain medium (or called amplified medium). The tunable fiber grating can be mechanical tuning fiber grating, electrical tuning fiber grating or other kind tunable fiber grating.
Figure 5 schematically illustrates another embodiment of a tunable light source. The halogen lamp white light source is used as a wide band light source. The circulator is used to input the narrow band light signal reflected from tunable fiber grating into the gain medium (or called amplified block). 980nm pumping laser, WDM coupler and Erbium doped fiber are used as gain block. The tunable fiber grating can be mechanical tuning fiber grating, electrical tuning fiber grating or other kind tunable fiber grating.
Figure 6 schematically illustrates an embodiment of another tunable light source. It is very similar with the setup as in figure 1. One more 980/1550 WDM is used at the front of the tunable fiber grating to separate the 980nm wavelength and ISSOnm wavelength into two different channels. The 980nm wavelength signal will no come back to the gain medium (or called amplified block). Only 1550nm wavelength signal reflected by the tunable fiber grating will come back and will be amplified by the gain medium.
The tunable fiber gra;ing can be mechanical tuning fiber grating, electrical tuning fiber grating or other kind tunable fiber grating.
Figure 7 schematically illustrates another embodiment of a tunable light source. The light emitting diode (LED) is used as a wide band light source. The circulator is used to input the narrow band light signal reflected from the tunable fiber grating into the gain block.
The Raman amplifier is as gain block. The tunable fiber grating can be mechanical tuning fiber grating, electrical tuning fiber grating or other kind tunable fiber grating.
It is to be understood that these drawings are for purpose of illustrating the concepts of the invention and are not to scale.
Detailed description Referring to the drawings, figure 1 schematically illustrates a tunable light source 8 comprising a tunable fiber grating 3, one segment of Erbium doped fiber 4 as gain medium, one WDM coupler 2 to combine 1550nm signal and 980nm pumping laser, a 980nm pumping laser 1 is used to pump the Erbium doped fiber to generate a wide band ASE source. Most of the forward propagated wide band ASE source is transmitted. Only a narrow band signal is reflected by the tunable fiber grating. The narrow band reflected signal is reamplified by the Erbium doped fiber 4 and the output signal is a narrow band, amplified signal. The center wavelength of the tunable fiber grating 3 can be changed and tile wavelength of the output narrow band signal can also be changed. A
tunable light source is therefore generated. An isolator 5 at the end of the output port is used to prevent the back reflected light into the erbium doped fiber. At the end of tunable fiber grating pigtail, an angled facet 6 is used to prevent back reflected light into the system.
The tunable fiber grating in figure 1 can be mechanical tuning fiber grating.
The tunable fiber grating in figure 1 can also be temperature tunable fiber grating. The tunable fiber grating in figure 1 can also be electrical tuning fiber grating. The tunable fiber grating in figure 1 can also be magnetic tunable fiber grating.
The tunable fiber grating 3 in figure 1 can also be replaced by other kind tunable filters.
Like Fabry-Pero tunable filter.
The gain medium 4 can be the Erbium doped fiber. It can also be other kind doped material fiber. The gain medium can also be Ytterbium doped fiber or Erbium and ytterbium codoped fiber. The gain medium can also be Thulium doped fiber, Praseodymium doped fiber and Neodymium doped fiber. The doped fiber can be simple mode fiber, mufti mode fiber, double cladding single mode fiber, double cladding polarization maintain single mode fiber, double cladding mufti mode fiber, double cladding polarization maintain mufti mode fiber. The doped fiber can be silica fiber, telluride fiber, fluoride fiber, plastic fiber, polymer fiber or other kind fibers.
The pumping laser 1 can be 980nm single mode laser, 1480nm single mode laser, and 980nm mufti mode laser, 1480nm mufti mode laser. The pumping laser can also be other wavelength single mode or mufti mode laser. The pumping method can be directly pumping, side pumping, double cladding pumping.
t The wide band ASE source generated by erbium doped fiber can be replaced with a light emitting .diode (LED) as in figure 2. The LED can be edge light emitting diode (ELED) or superluminescent laser diode (SLD). The LED produces a wide range light signal source. A circulator is used here to only put the reflected narrow band light signal reflected by the tunable fiber grating into gain medium. A segment of erbium doped fiber is pumped by a 980ivm laser as gain medium to amplify the narrow band signal reflected from the tunable fiber grating. A WDM coupler is used to combine 980nm and 1 SSOnm wavelength together. An amplified narrow band signal is generated by the system. At the end of output port an isolator is used to prevent back reflected signal.
We also can use the backward propagating ASE source in Erbium doped fiber pumping with a 980nm pumping laser or 1480nm pumping laser as wide band light source.
Referring to the drawings of figure 3, a tunable light source 8 comprising a tunable fiber grating 3, one segment of Erbium doped fiber 4 as gain medium, one WDM coupler 2 to combine 1550nm signal and 980nm pumping laser, a 980nm pumping laser 1 is used to pump the Erbium doped fiber to generate a wide band ASE source. An isolator 5 is used to prevent the output back into the system. 6 is angled facet. In figure 3, the wide band backward propagated ASE source is reflected by the tunable fiber grating. The small portion of the wide band light reflected is amplified by the Erbium doped fiber pumped with a 980nm or 1480nm laser. A WDM 2 is used to combine the 980nm pumping laser and signal light before into Erbium doped fiber 4. At the end of the output port, an isolator 5 is used to prevent the signal coming back into the system.
The gain medium can also be a semiconductor amplifier as shown in figure 4.
The wide band light source is LED and a circulator is used to redirect the light signal reflected by tunable fiber grating into a semiconductor amplifier in figure 4. The semiconductor amplifier is used to amplify the signal. An isolator at the output port is used to prevent the output signal coming back into the system.
The wide band light source can also be a halogen lamp, mercury lamp or other white light source as shown in figure 5. Because the white light source has a very wide band spectrum, it is also very suitable as wide band light source. A tunable fiber grating is used to reflect a narrow band signal into the circulator and the circulator redirect the light signal into Erbium doped fiber. A WDM is used to combine the 980nm pump laser and signal into the Erbium doped fiber. At the end of the output port, an isolator is used to prevent the output signal back to the system. Angled facet is used at the another end of tunable fiber grating to reduce the reflection from the end of the fiber.
To enhance the output signal power, we can use two pumping lasers as shown in figure 6.
Two 980nm pumping lasers are used to get a stronger wide band source and more powerful pumping capability than a single pumping laser system. Two pumping lasers are two 980nm pumping lasers in figure 6. It could be one 980nm pumping laser and one 1480nm pumping laser. Or two 1480nm pumping lasers can be used in the system.
In the figure 6, I and 6 are two 980nm pumping lasers. 2 and 5 are two WDM couplers to combine the 980nm and signal. 4 is Erbium doped fiber and 3 is tunable fiber grating.
The gain medium can also be Raman amplifier as shown in figure 7. The wide band light source is LED and a circulator is used to redirect the light signal reflected by tunable fiber grating into a Raman amplifier in figure 7. A Raman amplifier is used to amplify the signal. An isolator at the output port is used to prevent the output signal coming back into the system.
In the invention a tunable optical fiber light source device comprising:
A tunable optical grating fiber, a gain medium, a wide band light source.
In the invention, said tunable optical grating is a tunable Bragg grating;
In the invention, said tunable optical grating is a tunable tilted Bragg grating;
In the invention, said tunable optical grating is a tunable long period grating;
In the invention, said tunable optical grating is a Febry-Perot interference filter, In the invention, said gain medium is segment of Erbium doped fiber, a pumping laser, and a WDM coupler.
In the invention, said gain medium is semiconductor amplifier.
In the invention, said gain medium is Raman amplifier.
'_n ~he invention, said wide band light source is ASE source produced by the gain medium composed of Erbium doped fiber, pumping laser, WDM coupler.
In the invention, said wide band light source is a light emitting diode (LED) including surface light emitting diode (SLED) and edge light emitting diode (ELED).
In the invention, said wide band light source is the noise signal from Raman amplifier.
In the invention, said wide band light source is the noise signal from semiconductor amplifier.
In the invention, said wide band light is a white light source, like halogen lamp, mercury lamp, and deuterium lamp.
In the invention, WDM couplers are used to combine the signal and pump laser.
In the invention, isolators are used to prevent the light coming back into the system.
In the invention, circulators are used to redirect the light reflected by the tunable fiber grating into the gain medium.
In the invention, Erbium doped fiber can be replaced with other doped fibers like Ytterbium doped fiber, Ytterbium and Erbium codoped fiber.
In the invention, Erbium doped fiber can be replaced with Thulium doped fiber, Praseodymium doped fiber and Neodymium doped fiber.
In the invention, the doped fiber can be simple mode doped fiber, multi mode doped fiber.
In the invention, the doped fiber can be double cladding single mode doped fiber, double cladding polarization maintaining single mode doped fiber, double cladding multi mode doped fiber, double cladding polarization maintain multi mode doped fiber.
In the invention, the doped fiber can be silica fiber, telluride fiber, fluoride fiber, plastic fiber, polymer fiber or other kind fibers.
In.the invention, the pumping laser can be 980nm single mode laser, 1480nm single mode laser, and 980nm multi mode laser, 1480nm multi mode laser.
In the invention, the pumping laser can also be other wavelength single mode or multi mode laser. The pumping method can be directly pumping, side pumping, double cladding pumping.
In the invention, a gain flattening tilter can be used to flat the output light source in a wide band range.
References:
<1>. Morey W.M., Ball G.A., and Metlz G.:" Photoinduced Bragg Gratings in Optical fibers", Optics and Photonics News, February 1994, pp.8-14 <2>. G.A. Ball, W.W.Morey, and W.H. Glenn, :"Standing-Wave Monomode Erbium Fiber Laser", IEEE Photonics Technology Letters, vol. 3, pp.613-615(1991) <3>. K. O. Hill and G. Meltz, "Fiber Bragg Grating Technology Fundamentals and Overview", Journal of Lightwave Technology, vol. 1 S, pp. 1263-1276(1997) <4>. K.O. Hill, Y. Fujii, D.C. Hohnson, and B.S. Kawasaki, "photo-sensitivity in optical fiber waveguides: Application to reflection filter fabrication, " Appl. Phys.
Lett., Vol. 32, pp. 647-649( 1978).
<5>. G. Meltz, W. W. Morey and W.H. Glenn, "Formation of Bragg Gratings in optical fibers by transverse holographic method", Optics Letters, vol. 14, pp.823-825(1989) <6>. Mark Krol and Jaymin Amin, "Components and architectures for fixed and reconfigurable optical add/drop multiplexers", Bragg Gratings, Photosensitivity, and Poling in Glass Waveguides'99, Stuart, Florida, p. 4( 1999) <7>. Quetel et al., 1996 Technical Digest Series, Conf. on Optical Fiber Communication, San Jose, Calif., Feb. 25-Mar. 1, 1996, Vol. 2, p. 120, paper No. WF6.
<8>. G.A.Ball and W.W.Morey Optics Letters, Vol. 19, pp. 1979(1994).
<9>. Pin Long, patent in pending(April, 2000) <10>. M.H.Reeve, A.R.Hunwicks, W.Zhao, S.G.Methley, L.Bickers, and S.Hornung, "LED spectral slicing for single-mode local loop applications," Electronics Letters, vol.
24, pp.389-390(1988) <11>. J.S. Lee, Y.C. Chuang, and D.J.DiGiovanni, ''Spectrum-sliced fiber amplifier light source for multi~hannel WDM applications, " IEEE Photon. Technol. Lett., vol.5, pp 1458-1461 ( 1993) <12>. D.K.Jung, S.K.Shin, C.H.Lee, and Y.C.Chung, "Wavelength-division-multiplexed passive optical network based on spectrum-slicing techniques," IEEE Photon.
Technol.
T °~~.., vo1.10, pp.1334-1336(1998)
Figure I schematically illustrates an embodiment of a tunable light source.
The 980nm pumping laser, WDM coupler and Erbium doped fiber are used as gain medium (or called amplified block). The ASE source coming from IJrbium doped fiber pumped by 980nm pumping laser is used as wide band light source. The tunable fiber grating can be mechanical tuning fiber grating, electrical tuning fiber grating or other kind tunable fiber grating.
Figure 2 schematically illustrates another embodiment of a tunable light source. The light emitting diode(LED) is used as a wide band light source. The circulator is used to put the narrow band light signal reflected from tunable fiber grating into the gain block. 980nm pumping laser, WDM coupler and Erbium doped fiber are used as gain medium. The tunable fiber grating can be mechanical tuning fiber grating, electrical tuning fiber grating or other kind tunable fiber grating.
Figure 3 schematically illustrates another embodiment of a tunable light source. The ASE
source coming from Erbium doped fiber pumped by 980nm pumping laser is used as wide band source. The 980nm pumping laser, WDM coupler and Erbium doped fiber is also used as gain medium at same time. The back transmitted ASE signal from the Erbium doped fiber is used as wide band light source. The tunable fiber grating can be mechanical tuning fiber grating, electrical tuning fiber grating or other kind tunable fiber grating.
Figure 4 schematically illustrates another embodiment of a tunable light source. The light emitting diode (L>vD) is used as a wide band light source. The circulator is used to put the narrow band light signal reflected from the tunable fiber grating into the gain medium (or amplified block) for being amplified. The semiconductor amplifier is used as gain medium (or called amplified medium). The tunable fiber grating can be mechanical tuning fiber grating, electrical tuning fiber grating or other kind tunable fiber grating.
Figure 5 schematically illustrates another embodiment of a tunable light source. The halogen lamp white light source is used as a wide band light source. The circulator is used to input the narrow band light signal reflected from tunable fiber grating into the gain medium (or called amplified block). 980nm pumping laser, WDM coupler and Erbium doped fiber are used as gain block. The tunable fiber grating can be mechanical tuning fiber grating, electrical tuning fiber grating or other kind tunable fiber grating.
Figure 6 schematically illustrates an embodiment of another tunable light source. It is very similar with the setup as in figure 1. One more 980/1550 WDM is used at the front of the tunable fiber grating to separate the 980nm wavelength and ISSOnm wavelength into two different channels. The 980nm wavelength signal will no come back to the gain medium (or called amplified block). Only 1550nm wavelength signal reflected by the tunable fiber grating will come back and will be amplified by the gain medium.
The tunable fiber gra;ing can be mechanical tuning fiber grating, electrical tuning fiber grating or other kind tunable fiber grating.
Figure 7 schematically illustrates another embodiment of a tunable light source. The light emitting diode (LED) is used as a wide band light source. The circulator is used to input the narrow band light signal reflected from the tunable fiber grating into the gain block.
The Raman amplifier is as gain block. The tunable fiber grating can be mechanical tuning fiber grating, electrical tuning fiber grating or other kind tunable fiber grating.
It is to be understood that these drawings are for purpose of illustrating the concepts of the invention and are not to scale.
Detailed description Referring to the drawings, figure 1 schematically illustrates a tunable light source 8 comprising a tunable fiber grating 3, one segment of Erbium doped fiber 4 as gain medium, one WDM coupler 2 to combine 1550nm signal and 980nm pumping laser, a 980nm pumping laser 1 is used to pump the Erbium doped fiber to generate a wide band ASE source. Most of the forward propagated wide band ASE source is transmitted. Only a narrow band signal is reflected by the tunable fiber grating. The narrow band reflected signal is reamplified by the Erbium doped fiber 4 and the output signal is a narrow band, amplified signal. The center wavelength of the tunable fiber grating 3 can be changed and tile wavelength of the output narrow band signal can also be changed. A
tunable light source is therefore generated. An isolator 5 at the end of the output port is used to prevent the back reflected light into the erbium doped fiber. At the end of tunable fiber grating pigtail, an angled facet 6 is used to prevent back reflected light into the system.
The tunable fiber grating in figure 1 can be mechanical tuning fiber grating.
The tunable fiber grating in figure 1 can also be temperature tunable fiber grating. The tunable fiber grating in figure 1 can also be electrical tuning fiber grating. The tunable fiber grating in figure 1 can also be magnetic tunable fiber grating.
The tunable fiber grating 3 in figure 1 can also be replaced by other kind tunable filters.
Like Fabry-Pero tunable filter.
The gain medium 4 can be the Erbium doped fiber. It can also be other kind doped material fiber. The gain medium can also be Ytterbium doped fiber or Erbium and ytterbium codoped fiber. The gain medium can also be Thulium doped fiber, Praseodymium doped fiber and Neodymium doped fiber. The doped fiber can be simple mode fiber, mufti mode fiber, double cladding single mode fiber, double cladding polarization maintain single mode fiber, double cladding mufti mode fiber, double cladding polarization maintain mufti mode fiber. The doped fiber can be silica fiber, telluride fiber, fluoride fiber, plastic fiber, polymer fiber or other kind fibers.
The pumping laser 1 can be 980nm single mode laser, 1480nm single mode laser, and 980nm mufti mode laser, 1480nm mufti mode laser. The pumping laser can also be other wavelength single mode or mufti mode laser. The pumping method can be directly pumping, side pumping, double cladding pumping.
t The wide band ASE source generated by erbium doped fiber can be replaced with a light emitting .diode (LED) as in figure 2. The LED can be edge light emitting diode (ELED) or superluminescent laser diode (SLD). The LED produces a wide range light signal source. A circulator is used here to only put the reflected narrow band light signal reflected by the tunable fiber grating into gain medium. A segment of erbium doped fiber is pumped by a 980ivm laser as gain medium to amplify the narrow band signal reflected from the tunable fiber grating. A WDM coupler is used to combine 980nm and 1 SSOnm wavelength together. An amplified narrow band signal is generated by the system. At the end of output port an isolator is used to prevent back reflected signal.
We also can use the backward propagating ASE source in Erbium doped fiber pumping with a 980nm pumping laser or 1480nm pumping laser as wide band light source.
Referring to the drawings of figure 3, a tunable light source 8 comprising a tunable fiber grating 3, one segment of Erbium doped fiber 4 as gain medium, one WDM coupler 2 to combine 1550nm signal and 980nm pumping laser, a 980nm pumping laser 1 is used to pump the Erbium doped fiber to generate a wide band ASE source. An isolator 5 is used to prevent the output back into the system. 6 is angled facet. In figure 3, the wide band backward propagated ASE source is reflected by the tunable fiber grating. The small portion of the wide band light reflected is amplified by the Erbium doped fiber pumped with a 980nm or 1480nm laser. A WDM 2 is used to combine the 980nm pumping laser and signal light before into Erbium doped fiber 4. At the end of the output port, an isolator 5 is used to prevent the signal coming back into the system.
The gain medium can also be a semiconductor amplifier as shown in figure 4.
The wide band light source is LED and a circulator is used to redirect the light signal reflected by tunable fiber grating into a semiconductor amplifier in figure 4. The semiconductor amplifier is used to amplify the signal. An isolator at the output port is used to prevent the output signal coming back into the system.
The wide band light source can also be a halogen lamp, mercury lamp or other white light source as shown in figure 5. Because the white light source has a very wide band spectrum, it is also very suitable as wide band light source. A tunable fiber grating is used to reflect a narrow band signal into the circulator and the circulator redirect the light signal into Erbium doped fiber. A WDM is used to combine the 980nm pump laser and signal into the Erbium doped fiber. At the end of the output port, an isolator is used to prevent the output signal back to the system. Angled facet is used at the another end of tunable fiber grating to reduce the reflection from the end of the fiber.
To enhance the output signal power, we can use two pumping lasers as shown in figure 6.
Two 980nm pumping lasers are used to get a stronger wide band source and more powerful pumping capability than a single pumping laser system. Two pumping lasers are two 980nm pumping lasers in figure 6. It could be one 980nm pumping laser and one 1480nm pumping laser. Or two 1480nm pumping lasers can be used in the system.
In the figure 6, I and 6 are two 980nm pumping lasers. 2 and 5 are two WDM couplers to combine the 980nm and signal. 4 is Erbium doped fiber and 3 is tunable fiber grating.
The gain medium can also be Raman amplifier as shown in figure 7. The wide band light source is LED and a circulator is used to redirect the light signal reflected by tunable fiber grating into a Raman amplifier in figure 7. A Raman amplifier is used to amplify the signal. An isolator at the output port is used to prevent the output signal coming back into the system.
In the invention a tunable optical fiber light source device comprising:
A tunable optical grating fiber, a gain medium, a wide band light source.
In the invention, said tunable optical grating is a tunable Bragg grating;
In the invention, said tunable optical grating is a tunable tilted Bragg grating;
In the invention, said tunable optical grating is a tunable long period grating;
In the invention, said tunable optical grating is a Febry-Perot interference filter, In the invention, said gain medium is segment of Erbium doped fiber, a pumping laser, and a WDM coupler.
In the invention, said gain medium is semiconductor amplifier.
In the invention, said gain medium is Raman amplifier.
'_n ~he invention, said wide band light source is ASE source produced by the gain medium composed of Erbium doped fiber, pumping laser, WDM coupler.
In the invention, said wide band light source is a light emitting diode (LED) including surface light emitting diode (SLED) and edge light emitting diode (ELED).
In the invention, said wide band light source is the noise signal from Raman amplifier.
In the invention, said wide band light source is the noise signal from semiconductor amplifier.
In the invention, said wide band light is a white light source, like halogen lamp, mercury lamp, and deuterium lamp.
In the invention, WDM couplers are used to combine the signal and pump laser.
In the invention, isolators are used to prevent the light coming back into the system.
In the invention, circulators are used to redirect the light reflected by the tunable fiber grating into the gain medium.
In the invention, Erbium doped fiber can be replaced with other doped fibers like Ytterbium doped fiber, Ytterbium and Erbium codoped fiber.
In the invention, Erbium doped fiber can be replaced with Thulium doped fiber, Praseodymium doped fiber and Neodymium doped fiber.
In the invention, the doped fiber can be simple mode doped fiber, multi mode doped fiber.
In the invention, the doped fiber can be double cladding single mode doped fiber, double cladding polarization maintaining single mode doped fiber, double cladding multi mode doped fiber, double cladding polarization maintain multi mode doped fiber.
In the invention, the doped fiber can be silica fiber, telluride fiber, fluoride fiber, plastic fiber, polymer fiber or other kind fibers.
In.the invention, the pumping laser can be 980nm single mode laser, 1480nm single mode laser, and 980nm multi mode laser, 1480nm multi mode laser.
In the invention, the pumping laser can also be other wavelength single mode or multi mode laser. The pumping method can be directly pumping, side pumping, double cladding pumping.
In the invention, a gain flattening tilter can be used to flat the output light source in a wide band range.
References:
<1>. Morey W.M., Ball G.A., and Metlz G.:" Photoinduced Bragg Gratings in Optical fibers", Optics and Photonics News, February 1994, pp.8-14 <2>. G.A. Ball, W.W.Morey, and W.H. Glenn, :"Standing-Wave Monomode Erbium Fiber Laser", IEEE Photonics Technology Letters, vol. 3, pp.613-615(1991) <3>. K. O. Hill and G. Meltz, "Fiber Bragg Grating Technology Fundamentals and Overview", Journal of Lightwave Technology, vol. 1 S, pp. 1263-1276(1997) <4>. K.O. Hill, Y. Fujii, D.C. Hohnson, and B.S. Kawasaki, "photo-sensitivity in optical fiber waveguides: Application to reflection filter fabrication, " Appl. Phys.
Lett., Vol. 32, pp. 647-649( 1978).
<5>. G. Meltz, W. W. Morey and W.H. Glenn, "Formation of Bragg Gratings in optical fibers by transverse holographic method", Optics Letters, vol. 14, pp.823-825(1989) <6>. Mark Krol and Jaymin Amin, "Components and architectures for fixed and reconfigurable optical add/drop multiplexers", Bragg Gratings, Photosensitivity, and Poling in Glass Waveguides'99, Stuart, Florida, p. 4( 1999) <7>. Quetel et al., 1996 Technical Digest Series, Conf. on Optical Fiber Communication, San Jose, Calif., Feb. 25-Mar. 1, 1996, Vol. 2, p. 120, paper No. WF6.
<8>. G.A.Ball and W.W.Morey Optics Letters, Vol. 19, pp. 1979(1994).
<9>. Pin Long, patent in pending(April, 2000) <10>. M.H.Reeve, A.R.Hunwicks, W.Zhao, S.G.Methley, L.Bickers, and S.Hornung, "LED spectral slicing for single-mode local loop applications," Electronics Letters, vol.
24, pp.389-390(1988) <11>. J.S. Lee, Y.C. Chuang, and D.J.DiGiovanni, ''Spectrum-sliced fiber amplifier light source for multi~hannel WDM applications, " IEEE Photon. Technol. Lett., vol.5, pp 1458-1461 ( 1993) <12>. D.K.Jung, S.K.Shin, C.H.Lee, and Y.C.Chung, "Wavelength-division-multiplexed passive optical network based on spectrum-slicing techniques," IEEE Photon.
Technol.
T °~~.., vo1.10, pp.1334-1336(1998)
Claims
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2318675 CA2318675A1 (en) | 2000-09-19 | 2000-09-19 | Tunable optical fiber light source |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2318675 CA2318675A1 (en) | 2000-09-19 | 2000-09-19 | Tunable optical fiber light source |
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| CA2318675A1 true CA2318675A1 (en) | 2002-03-19 |
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| CA 2318675 Abandoned CA2318675A1 (en) | 2000-09-19 | 2000-09-19 | Tunable optical fiber light source |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012072217A1 (en) * | 2010-12-01 | 2012-06-07 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Fiber amplifier system |
| CN102761048A (en) * | 2012-05-16 | 2012-10-31 | 中国科学院上海光学精密机械研究所 | Tunable Raman fiber laser |
-
2000
- 2000-09-19 CA CA 2318675 patent/CA2318675A1/en not_active Abandoned
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012072217A1 (en) * | 2010-12-01 | 2012-06-07 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Fiber amplifier system |
| CN102761048A (en) * | 2012-05-16 | 2012-10-31 | 中国科学院上海光学精密机械研究所 | Tunable Raman fiber laser |
| CN102761048B (en) * | 2012-05-16 | 2014-04-09 | 中国科学院上海光学精密机械研究所 | Tunable Raman fiber laser |
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