Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Priority
Acknowledgment is made of applicant’s claim for foreign priority under 35 U.S.C. 119 (a)-(d). The certified copy has been filed in parent Application No. CN-2023100986607, filed on 02/10/2023. Translation of the certified copy is required to perfect the priority claim made in this application.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 4-6 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 4 recites the limitation “the input port”. There is insufficient antecedent basis for this limitation in the claim. For purposes of examination, this limitation will be read as “an input port”.
Claim 4 recites the limitation “the inner cladding”. There is insufficient antecedent basis for this limitation in the claim. For purposes of examination, this limitation will be read as “an inner cladding”.
Claim 5 recites the limitation “ the of the first fiber Bragg grating”. It is unclear what of the first fiber Bragg grating is being referred to, additionally rendering the scope of the claim indefinite. For purposes of examination, this limitation will be read as “the reflectivity of the first fiber Bragg grating”.
Claim 5 recites the limitation “a certain wavelength within the emission band”. It is unclear which wavelength in the spectrum of the emission band is being referred to, rendering the scope of the claim indefinite. For purposes of examination, this limitation will be read as “any wavelength within the emission band”.
Claim 6 recites the limitation “the central wavelength”. There is insufficient antecedent basis for this limitation in the claim. For purposes of examination, this limitation will be read as “a central wavelength”.
Claim 6 recites the limitation “a certain wavelength within the emission band”. It is unclear which wavelength in the spectrum of the emission band is being referred to, rendering the scope of the claim indefinite. For purposes of examination, this limitation will be read as “any wavelength within the emission band”.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim(s) 1 is/are rejected under 35 U.S.C. 103 as being unpatentable over Liu et al., hereinafter Liu (Chinese Patent Application No. 110429461) in view of Henderson-Sapir et al. (NPL, “Recent Advances in 3.5 μm Erbium-Doped Mid-Infrared Fiber Lasers”) hereinafter Henderson-Sapir, in view of Shori (U.S. Patent Application No. 2007/0297482), in view of Ilday et al. (WO 2021/137810), hereinafter Ilday.
Regarding Claim 1, Liu teaches a 2.8 µm (see examiner provided translation, Abstract) and 1.6 µm (see examiner provided translation, Abstract) dual-wavelength mid-infrared fiber laser (see examiner provided translation, Abstract), comprising a first pump source (Fig 2, “21”; see translated except A below), a first fiber Bragg grating (Fig 2, “24”; see translated except A below), a second fiber Bragg grating (Fig 2, “26”; see translated except A below), a second pump source(Fig 2, “22”; see translated except A below), a fiber combiner (Fig 2, “23”; see translated except A below), a double cladding Er-doped fluoride fiber (Fig 2, “25”; see translated except A below); pump lights generated by the first pump source and the second pump source are combined by the fiber combiner and then injected into the double cladding Er-doped fluoride fiber to provide gain for both 2.8 µm and 1.6 µm transitions, as well as to suppress self-termination of 1.6 µm laser caused by long level lifetime (see translated excerpt B below), enabling 2.8 µm and 1.6 µm dual-wavelength transmission simultaneously based on a single piece of double cladding Er-doped fluoride fiber (see examiner provided translation, Abstract; Fig. 2, single Er-doped fiber “25”).
Liu does not teach: 3.5 µm as one of the dual-wavelengths; a long pass filter; that an output end of the double cladding Er-doped fluoride fiber is perpendicularly cleaved, the cleaved output end and the first fiber Bragg grating forms a 3.5 µm resonator, the cleaved output end and the second fiber Bragg grating forms a 2.8 µm resonator; the first pump source and the second pump source correspond to a ground state absorption with an Er ion
I
4
15
/
2
→
I
4
11
/
2
transition and an excited state absorption with an Er ion
I
4
13
/
2
→
F
4
9
/
2
respectively.
Henderson-Sapir teaches: an erbium doped fiber laser with 3.5 µm operating wavelength in the mid-infrared (Fig. 1: “
E
r
3
+
[18, 19]” development since 2012; “
E
r
3
+
[20]”; “
E
r
3
+
[21]” development since 2012); an erbium doped fiber laser with 1.6 µm operating wavelength in the near-infrared (Fig. 1,“
E
r
3
+
[10]”) , an erbium doped fiber laser with 2.8 µm operating wavelength in the near-infrared (Fig. 1,“
E
r
3
+
[13]”); 3.5 µm lasing with Er ion
F
4
9
/
2
→
I
4
9
/
2
transition (Fig. 3)); 2.8 µm lasing with Er ion
I
4
11
/
2
→
I
13
/
2
transition (Fig. 3); that an output end of the double cladding Er-doped fluoride fiber is perpendicularly cleaved (Fig. 6 see “ZBLAN fibre” with straight ends ; Section IV, first paragraph, ends are “butted against dichroic mirrors”). It can be necessarily understood by someone having ordinary skill that a normal-cleaved, flat-cleaved, or butt-coupled fiber has an output end which is perpendicularly cleaved, in the sense that normal-cleaved and flat-cleaved are synonymous to perpendicularly cleaved, and that perpendicularly cleaved optical fibers are used for butt-coupling. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to: emit at 2.8 µm and 3.5 µm as taught by Henderson-Sapir in the dual-wavelength mid-infrared fiber laser as taught by Liu for the benefit of emitting longer mid-infrared spectrum while maintaining population inversion as taught by Henderson-Sapir (Fig. 5, see 2.8 µm and 3.5 µm lasing transitions each end above the ground state
I
4
15
/
2
); to perpendicularly cleave the fiber so that it can be butt-coupled for maximizing light transmission; utilize the cleaved output end and the first fiber Bragg grating as a 3.5 µm resonator, the cleaved output end and the first fiber Bragg grating forms a 2.8 µm resonator in the device of Liu and Henderson-Sapir so that each pump light is absorbed completely in the Er-doped fiber to improve the output fiber slope efficiency as taught by Liu (see excerpts C and D of Liu below).
Liu and Henderson-Sapir do not teach: a long pass filter; the first pump source and the second pump source correspond to a ground state absorption with an Er ion
I
4
15
/
2
→
I
4
11
/
2
transition and an excited state absorption with an Er ion
I
4
13
/
2
→
F
4
9
/
2
respectively.
Shori teaches a ground state absorption with an Er ion
I
4
15
/
2
→
I
4
11
/
2
transition (Fig. 2; paragraph [0014]-[0015]) and an excited state absorption with an Er ion
I
4
13
/
2
→
I
4
9
/
2
(Fig. 2). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to: correspond the first and second pump in the device of Liu and Henderson-Sapir with the ground state
I
4
15
/
2
→
I
4
11
/
2
and excited state
I
4
13
/
2
→
I
4
9
/
2
transitions of Shori, for the benefit of lasing with a virtual ground state to maintain population inversion; modify the second pump of Shori with the excited state
F
4
9
/
2
, such that the second pump in the device of Liu and Henderson-Sapir corresponds to the excited state absorption with an Er ion
I
4
13
/
2
→
F
4
9
/
2
, for the benefit of pumping to the energy state necessary for a 3.5 µm lasing as taught by Henderson-Sapir above. Liu, Henderson-Sapir, and Shori, do not teach a long pass filter.
Ilday teaches a long pass filter (page 4, line 21). Therefore, it would have been obvious before the effective filing date of the claimed invention to add a long pass filter as taught by Ilday in the device of Liu, Henderson-Sapir, and Shori for the benefit of selectively emitting the mid-infrared spectrum which the device is lasing.
Claim 2 is rejected under 35 U.S.C 103 as being unpatentable by Liu, Henderson-Sapir, Shori, and Ilday, in view of Wang et al. (U.S. Patent Application 2023/0038367), hereinafter Wang,
Regarding Claim 2, Liu, Henderson-Sapir, Shori, and Ilday, teaches the device of Claim 1.
Liu as modified does not teach: the first pump source is a multimode laser with an output wavelength of 0.98 μm.
Liu further teaches that the first pump source has an output wavelength of 0.98 μm (see translated except E below; 976 nm = 0.98 μm when converted to μm and rounded to the same number of significant figures as the applicant’s output wavelength). Therefore, it would have been obvious to someone having ordinary skill in the art before the effective filing date of the claimed invention for the first pump source to have an output wavelength of 0.98 μm as taught by Liu in the device of Liu, Henderson-Sapir, Shori, and Ilday, for sufficient population inversion of the ground state to occur for mid-infrared lasing. Liu, Henderson-Sapir, Shori, and Ilday, do not teach that the first pump source is a multimode laser.
Wang teaches a multimode pump source (Abstract). Therefore, it would have been obvious to someone having ordinary skill in the art before the effective filing date of the claimed invention to utilize a multimode laser as taught by Liu as the first pump source in the device of Liu, Henderson-Sapir, Shori, and Ilday, for the benefit of increasing the device’s pump conversion efficiency as taught by Wang (paragraph [0004]) to compensate for the higher quantum defect of the shorter pump wavelength.
Claim 3 is rejected under 35 U.S.C 103 as being unpatentable by Liu, Henderson-Sapir, Shori, and Ilday, in view of Kurkov et al. (NPL, “All-fiber holmium lasers pumped at
λ
=1.15 μm”), hereinafter Kurkov, in view of Wang et al. (U.S. Patent Application 2023/0038367), hereinafter Wang.
Regarding Claim 3, Liu, Henderson-Sapir, Shori, and Ilday, teaches the device of Claim 1.
Liu as modified does not teach: the second pump source is a single-transverse mode Yb-doped fiber laser with an output wavelength of 1.15 µm.
Kurkov teaches a pump source as a Yb-doped fiber laser (Abstract) with an output wavelength of 1.15 µm (Abstract, 1147 nm = 1.15 μm when converted to μm and rounded to the same number of significant figures as the applicant’s output wavelength). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to: utilize a Yb-doped fiber laser with an output wavelength of 1.15 µm as taught by Kurkov as the second pump source in the device of Liu, Henderson-Sapir, Shori, and Ilday to prevent bottlenecking at the lower lasing state, for the benefit of increasing conversion efficiency in the device. Liu, Henderson-Sapir, Shori, Ilday, and Kurkov do not teach that the second pump source is a single transverse-mode fiber.
Wang teaches a single transverse-mode fiber (paragraph [0004]). It would have been obvious to someone having ordinary skill in the art before the effective filing date of the claimed invention to: utilize a single-transverse mode fiber laser for the second pump source as taught by Wang in the device of Liu, Henderson-Sapir, Shori, Ilday, and Kurkov to increase the pump conversion efficiency of the device by reducing pump power loss as taught by Wang (paragraph [0101], comparison of type C in Fig. 6C to type A in Fig. 6A).
Claim 4 is rejected under 35 U.S.C 103 as being unpatentable by Liu, Henderson-Sapir, Shori, and Ilday, further in view of Liu, in view of Kurkov, in view of Wang.
Regarding Claim 4, Liu, Henderson-Sapir, Shori, and Ilday teaches the device of Claim 1.
Liu as modified does not teach: an input port of the fiber combiner is a double-cladding fiber which is capable of propagating 1.15 μm single-mode pump inside the core and propagating 0.98 μm multimode pump laser inside the inner cladding.
Liu further teaches: the input port of the fiber combiner includes the two pump source fibers (Fig. 2, see inputs on the left of the fiber combiner “23”); that the output fiber is a double cladding fiber; that the first pump source has an output wavelength of 0.98 μm (see translated except E; 976 nm = 0.98 μm when converted to μm and rounded to the same number of significant figures as the applicant’s output wavelength); that the first pump source is coupled into the inner cladding of the double cladding fiber (see examiner provided translation, Abstract); that the second pump source is coupled inside the core of the double-cladding fiber (see examiner provided translation, Abstract). Thus, it is necessarily understood by someone having ordinary skill in the art that the output fiber is capable of propagating second pump source in the inner core and propagating 0.98 μm pump source inside the inner cladding, in the sense that the first pump forms the inner cladding and outputs 0.98 μm. Liu, Henderson-Sapir, Shori, and Ilday do not teach: a multimode pump laser; a 1.15 μm single-mode pump laser.
Kurkov teaches a 1.15 µm pump laser (Abstract, 1147 nm = 1.15 μm when converted to μm and rounded to the same number of significant figures as the applicant’s wavelength). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to: utilize a 1.15 μm pump laser as taught by Kurkov in the device of Liu, Henderson-Sapir, Shori, and Ilday to prevent bottlenecking at the lower lasing state, for the benefit of increasing conversion efficiency in the device. Liu, Henderson-Sapir, Shori, Ilday, and Kurkov do not teach: single-mode pump laser; multimode pump laser.
Wang teaches: a single-mode pump laser (paragraph [0004]); a multimode pump laser (paragraph [0004]; Abstract). Therefore, it would have been obvious to someone having ordinary skill in the art before the effective filing date of the claimed invention to: utilize a multimode pump laser as taught by Liu as the first pump source in the device of Liu, Henderson-Sapir, Shori, Ilday and Kurkov, for the benefit of increasing the device’s pump conversion efficiency as taught by Wang (paragraph [0004]) to compensate for the higher quantum defect of the shorter pump wavelength; utilize a single-mode pump laser for the second pump source as taught by Wang in the device of Liu, Henderson-Sapir, Shori, Ilday, and Kurkov to increase the pump conversion efficiency of the device by reducing pump power loss as taught by Wang (paragraph [0101], comparison of type C in Fig. 6C to type A in Fig. 6A); that the output fiber is capable of propagating 1.15 μm as taught by Kurkov, single-mode pump laser as taught by Wang, inside the core as taught by Liu, and propagating 0.98 μm multimode pump laser as taught by Wang, inside the inner cladding as taught by Liu, in the device of Liu, Henderson-Sapir, Shori, Ilday, and Kurkov, for the benefit of propagating the first and second pump laser into a single Er-doped fiber.
Claims 5 and 6 are rejected under 35 U.S.C 103 as being unpatentable by Liu, Henderson-Sapir, Shori, and Ilday, further in view of Liu, in view of Bharathan et al. (NPL, “Optimized laser written ZBLAN fiber Bragg gratings with high reflectivity and low loss”), hereinafter Bharathan.
Regarding Claim 5, Liu, Henderson-Sapir, Shori, and Ilday teaches the device of Claim 1.
Liu as modified does not teach: a central wavelength of the first fiber Bragg grating is a certain wavelength within the emission band of Er ion
F
4
9
/
2
→
I
4
9
/
2
transition, the reflectivity of the first fiber Bragg grating is greater than 99.5%, the FWHM is narrower than 5nm and the insertion loss at pump wavelengths is lower than 0.5 dB.
Liu further teaches: the central wavelength of the first fiber Bragg grating is one of the dual-wavelengths (see translated excerpt F below , “working wavelength”, 2.8 μm and 1.6 μm; see examiner provided translation, Abstract for 2.8 μm and 1.6 μm dual-wavelengths); Liu teaches a reflectivity of 99 % (see translated excerpt G); the FWHM is narrower than 5 nm (see translated excerpt F below, “working bandwidth”). Therefore, it would have been obvious before the effective filing date of the claimed invention for a central wavelength of the first fiber Bragg grating to be a certain wavelength within the emission band of Er ion
F
4
9
/
2
→
I
4
9
/
2
transition, as taught to be 3.5 μm lasing by Henderson-Sapir in Claim 1, for the benefit of 3.5 μm optical saturation in the Er-doped fiber in the device of Liu, Henderson-Sapir, Shori, and Ilday.
However, in accordance with MPEP 2144.05 II, Optimization of Ranges: where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation. In the prior art the general conditions are disclosed, a fiber laser comprising a Bragg grating with a high reflectivity at the emission wavelength. Therefore, it would have been obvious to one of ordinary skill in the art at the time of the invention to obtain a workable range of values for the reflectivity of the Bragg grating by routine experimentation. It would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to utilize a first fiber Bragg grating with a reflectivity greater than 99.5% in the device of Liu, Henderson-Sapir, Shori, and Ilday for the benefit of locking 3.5 μm emission in the fiber laser. Liu, Henderson-Sapir, Shori, and Ilday do not teach: the insertion loss at pump wavelengths is lower than 0.5 dB.
Bharathan teaches a mid-infrared fiber Bragg grating wherein the insertion loss is lower than 0.5 dB (Table 1, sixth row; 0.34 dB/cm out-of-band loss with grating length 0.5 cm, thus 0.34 dB/cm multiplied by 0.5 cm = 0.17 dB insertion loss). Therefore, it would have been obvious before the effective filing date of the claimed invention for the first fiber Bragg grating in the device of Liu, Henderson-Sapir, Shori, Ilday, and Aydin to have an insertion loss at pump wavelengths lower than 0.5 dB, for the benefit of maximizing output power of the fiber laser.
Regarding Claim 6, Liu, Henderson-Sapir, Shori, and Ilday teach the device of Claim 1.
Liu as modified does not teach: a central wavelength of the second fiber Bragg grating is a certain wavelength within the emission band of the Er ion
I
4
11
/
2
→
I
13
/
2
transition; the reflectivity of the second fiber Bragg grating is greater than 99.5%; the FWHM is narrower than 5 nm; the insertion loss at pump wavelengths is lower than 0.5dB.
Liu further teaches: a central wavelength of the fiber Bragg grating is one of the dual-wavelengths (see translated excerpt F, “working wavelength”, 2.8 μm; see examiner provided translation, Abstract for 2.8 μm dual-wavelength); the reflectivity is 99% (see translated excerpt G); the FWHM is narrower than 5 nm (see translated excerpt F below, “working bandwidth”). It can be necessarily understood by someone of ordinary skill that 2.8 μm is in the emission band of Er ion
I
4
11
/
2
→
I
13
/
2
transition, in the sense that 2.8 μm is the emission wavelength of that Er ion transition as taught by Henderson-Sapir in Claim 1 above.
However, in accordance with MPEP 2144.05 II, Optimization of Ranges: Where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation. In the prior art the general conditions are disclosed, a fiber laser comprising a fiber Bragg grating with a high reflectivity at the emission wavelength. Therefore, it would have been obvious to one of ordinary skill in the art at the time of the invention to obtain a workable range of values for the reflectivity of the Bragg grating by routine experimentation. It would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to utilize a second fiber Bragg grating with a reflectivity greater than 99.5% in the device of Liu, Henderson-Sapir, Shori, and Ilday for the benefit of locking 2.8 μm emission in the fiber laser. Liu, Henderson-Sapir, Shori, and Ilday do not teach: the insertion loss at pump wavelengths is lower than 0.5 dB.
Bharathan teaches a mid-infrared fiber Bragg grating wherein the insertion loss is lower than 0.5 dB (Table 1, sixth row; 0.34 dB/cm out-of-band loss with grating length 0.5 cm, thus 0.34 dB/cm multiplied by 0.5 cm = 0.17 dB insertion loss). Therefore, it would have been obvious before the effective filing date of the claimed invention for the second fiber Bragg grating in the device of Liu, Henderson-Sapir, Shori, Ilday, and Aydin to have an insertion loss at pump wavelengths lower than 0.5 dB, for the benefit of maximizing output power of the fiber laser.
Claim 7 is rejected under 35 U.S.C 103 as being unpatentable by Liu, Henderson-Sapir, Shori, and Ilday, further in view of Thorlabs (NPL, “Longpass Dichroic Mirrors/Beamsplitters”).
Regarding Claim 7, Liu, Henderson-Sapir, Shori, and Ilday teach the device of Claim 1.
Liu as modified does not teach: that the long pass filter has a cutoff wavelength of 1.5 μm, a reflectivity at 0.98 μm and 1.15 μm are greater than 95%, and a transmission at both the 2.8 μm and 3.5 μm are greater than 95%.
Thorlabs teaches: a long pass filter(“DMLP1500TØ1/2" Longpass Dichroic Mirror, 1500 nm Cut-On”) which has a cutoff wavelength of 1.5 μm (“DMLP1500TØ1/2" Longpass Dichroic Mirror, 1500 nm Cut-On”); a long pass filter with reflectivity at 0.98 μm greater than 95% (“DMLP1180TØ1/2" Longpass Dichroic Mirror, 1180 nm Cut-On”; Figure G.21.1, see raw data at 980 nm = 0.98 μm reflectivity is 99.61% rounded to the nearest hundredth of a percent); a long pass filter with reflectivity at 1.15 μm greater than 95% (Figure G.22.1, see raw data, at 1050 nm = 1.15 μm reflectivity is 98.21% rounded to the nearest hundredth of a percent); a long pass filter with infrared transmission in the transmission band greater than 95% (“Longpass Dichroic Mirror/Beamsplitter: 1150 nm Cut-On Wavelength”, see specification table). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the long pass filter in the device of Liu, Henderson-Sapir, Shori, and Ilday to have a cutoff wavelength of 1.5 μm, a reflectivity at 1.15 μm greater than 95% as taught by Thorlabs for the benefit of allowing the 1.15 μm to absorb into the Er double-cladding fiber and prevent unabsorbed pump light emission; to transmit at the 2.8 μm and 3.5 μm wavelengths in the device of Liu, Henderson-Sapir, Shori, and Ilday with greater than 95% transmission as taught by Thorlabs for the benefit of selectively emitting the dual-wavelengths without also emitting either of the non-infrared unabsorbed pump light wavelengths.
In the examiner provided translation of Liu mailed with this office action are the following excerpts:
“the optical fibre laser of this invention comprises a first pump laser 21, the second pump laser 22, a combiner 23, a first optical fibre Bragg grating 24, double clad erbium-doped fluoride fiber 25, AlF3 end cap 28. wherein the first pump laser 21 for generating the first pump, the second pump laser 22 for generating a second pump, the first pump laser 21 and the second pump laser 22 respectively connected with the combiner 23, the first pump light and the second pump light so as to take generated is transmitted to the combiner 23 are combined into one beam; the first pumping light and the second pumping light after the combiner 23 combining the first coupling the pump light into the double-clad Er-doped fluoride fiber 25 of the cladding. coupling the second pump light into the double-clad erbium-doped fluoride fiber 25 in the core.”
“Further, in the present embodiment, the first pump laser 21 generates first pumping light whose wave length is 976nm, the first pumping light by the beam splitter 23 is coupled into the double-clad Er-doped fluoride fiber 25 of the cladding. by multi-pass core, excitation inside the core located on level 4I15 /2 ground state erbium ion pumping to the energy level 4I11 /2, so as to form a population inversion, so the level 4I11/2 and the level 4I13/2 is formed between 2.8 μm of the laser radiation. However, in this process because the erbium ions in the ion residence time on the excited energy level 4I13 /2 (9.0ms), which is far greater than the higher energy level 4I11 /2 of the residence time (6.9ms), and erbium ions will 4I11 /2 pumped from the high level to a higher energy level 4 F7/2, resulting in 4 I11/2 of erbium ion number is reduced, thereby resulting in insufficient particle inverted number laser energy level transition self-termination. “
“…the first pump light through the beam splitter 23 is coupled into the double-clad erbium-doped fluoride fiber 25 cladding, core, excitation by repeatedly traversing inside the core doped erbium ion, erbium ion number of the lower level to high level transition, once the upper level erbium ions excited radiation will form a wave, and then transmission back and forth between the optical resonant cavity, when the gain of the beam larger than a loss to obtain the laser output.”
“…. The working wavelength of the second fiber Bragg grating 26 is 1.6 μm, and the working bandwidth is less than 0.25 nm. The second fiber Bragg grating 26 reflects the second pump light that is not absorbed by the erbium ions back into the optical resonant cavity, so that the second pump light is completely absorbed by the double-clad erbium-doped fluoride fiber 25, Thereby, the laser radiation slope efficiency and the output power of the fiber laser are improved.”
“the double-wavelength pumping erbium-doped fluoride fibre laser, wherein the wavelength of the first pump light is 976nm.”
“In the dual-wavelength pumped erbium-doped fluoride fiber laser, the working wavelength of the first fiber Bragg grating is 2.8 μm, and the working bandwidth is less than 0.9 nm. In the dual-wavelength pumped erbium-doped fluoride fiber laser, the working wavelength of the second fiber Bragg grating is 1.6 μm, and the working bandwidth is less than 0.25 nm.”
“the first optical fibre Bragg grating 24 at the same time as the pump input mirror and the frequency selecting element, and a AlF3 end cap 28 form an optical resonant cavity 2.8 of μm laser, the 2.8 μm laser reflectance greater than 99%, the working bandwidth is less than 0.9nm.”
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant’s disclosure.
The following references teach a similar fiber laser:
Vallée WO 2011/00919
Delavaux U.S. Patent No. 5933437
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JASMIN KAUR MUNDI whose telephone number is (571)272-9755. The examiner can normally be reached Monday - Thursday, 8 a.m. - 6 p.m. ET.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, MinSun Harvey can be reached at (571) 272-1835. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/J.K.M./Examiner, Art Unit 2828
/XINNING(Tom) NIU/Primary Examiner, Art Unit 2828