CN1645771A - Optical pulse series spectral stretcher based on high nonlinear optic fibre - Google Patents
Optical pulse series spectral stretcher based on high nonlinear optic fibre Download PDFInfo
- Publication number
- CN1645771A CN1645771A CN 200510018146 CN200510018146A CN1645771A CN 1645771 A CN1645771 A CN 1645771A CN 200510018146 CN200510018146 CN 200510018146 CN 200510018146 A CN200510018146 A CN 200510018146A CN 1645771 A CN1645771 A CN 1645771A
- Authority
- CN
- China
- Prior art keywords
- pulse
- optical fiber
- spectrum
- highly nonlinear
- length
- 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.)
- Granted
Links
Landscapes
- Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
Abstract
The invention contains two different lengths of highly nonlinear fibers. A standard single-mode fiber is welded between them and is taken as wide- band coherent source of pulse repetition frequency of WDM 40 GHz.
Description
Technical field
The present invention relates to the device in the optical fiber communication, particularly a kind of 40GHz optical pulse series spectral stretcher device based on highly nonlinear optical fiber is to provide the broadband coherent source as the high pulse repetition frequency of wavelength division multiplexing (WDM).
Background technology
Develop rapidly and extensive use along with Internet (INTERNET) and IP technology, various novel band width service continue to bring out, society is exponential increase to the demand of amount of information, and optical fiber telecommunications system is owing to have huge bandwidth potential, and the ratio of occupying in communication system is with increasing.All-optical network based on dense wave division multipurpose (DWDM) technology has been acknowledged as the effective means of alleviating a growing message capacity difficult problem, and the approach commonly used that utilizes WDM technology to improve message capacity is to increase to participate in the multiplexing wavelength number and the data transfer rate of each wavelength channel in the communication system.In based on the ultrahigh speed of 40Gb/s transmission rate, ultra-wideband communication system, WDM technology and Optical Time Division Multiplexing (OTDM) and Optical Code Division Multiplexing (OCDM) technology are in conjunction with application, further improve power system capacity, need use the ultra-short pulse source of multi-wavelength high pulse repetition rate, it is exactly the method that realizes this light source that super continuous spectrums is composed section.
As shown in Figure 2: super continuous spectrums (Supercontinuum, be called for short SC) generation be meant that intensity is higher and short pulse that spectral width is limited by behind the nonlinear dielectric, produce many new frequency contents in its spectrum, spectral width is much larger than the spectrum of incident light.The method of section is composed in utilization to SC, can therefrom extract the different short pulse of a plurality of centre wavelengths of any live width, wherein each centre wavelength channel all has the pulse recurrence rate identical with the source light-pulse generator, realizes the multi-wavelength expansion of light-pulse generator thus.Because nonlinear dielectric commonly used is the passive device optical fiber the same with wavelength filter, so for the multi wave length illuminating source that is made of a plurality of discrete light sources, not only cost is low, and good stability.SC spectrum patterning method provides a kind of approach that realizes cheapness, stable multi-wavelength light-pulse generator, and the pulse train quality quality of each wavelength channel depends on the characteristic of SC spectrum.The flatness of stretched-out spectrum, width and coherence (being the longitudinal mode modulation depth) weigh three most important characteristic of SC spectrum.
The characteristic of SC spectrum is except outside the Pass having with employed pump pulse, also be decided by to be used for the type of nonlinear optical fiber of spectrum widening and the combination connecting mode of different qualities optical fiber, use different optical fiber can constitute different pulse spectrum stretchers with different fiber is connected by the various combination form.The generation of SC mainly contains three kinds of approach: the dispersion shifted optical fiber (DSF) that utilizes the higher-order soliton pinch effect; Utilize the chromatic dispersion of the adiabatic soliton compression optical fiber (DDF) that successively decreases; Utilization is from the normal dispersion fiber of phase modulated (SPM) effect.First method utilizes near the anomalous dispersion district of the pulse zero dispersion point of DSF to form higher-order soliton with compression pulse, spread-spectrum.When its subject matter was that pulse is propagated in the anomalous dispersion district of optical fiber, the coherence of SC spectrum can be subjected to modulating unsettled influence and deterioration, and the spectrum of opening up near pump pulse centre wavelength, have significantly and get deeply stuck in.Its group velocity delay of optical fiber (GVD) constant that second method adopts along optical fiber from outlying observation (β
2＜0) becomes normal value (β
2＞0), when pulse was propagated in this optical fiber, exhibition was composed in the normal dispersion district after peak power improves by adiabatic soliton compression in the anomalous dispersion district.This method requires the pump pulse of optic fibre input end will satisfy ground state orphan's condition, and this power that has just limited input pulse can not be higher, can cause low power spectral density behind the spectrum widening of pulse, is unfavorable for improving signal to noise ratio; And optical fiber dispersion must be that thermal insulation is successively decreased, normally used fiber lengths very long (＞1km), too high to the optical fiber fabrication technological requirement.With respect to the two kinds of methods in front, the third method has tangible advantage, thereby is widely used.
Use has the spectrum widening of the optical fiber of normal dispersion value as SC optical fiber realization pulse: when pulse is transmitted in this optical fiber, the frequency chirp that the GVD of SPM and normal dispersion introduces interacts, make the pulse time domain broadening on the one hand, the accumulation of this linear chrip can guarantee the smooth broadening of pulse spectrum on the other hand.The effect that its SC produces is mainly described by two following parameters: (1) L
D2/ L
NL, L wherein
D2Be 2nd order chromatic dispersion length, be defined as T
0 2/ | β
2|; L
NLBe non-lineal measure, be defined as 1/ (γ P
0), (2) L
D2/ L
D3, L wherein
D3Be third-order dispersion length, be defined as T
0 3/ | β
3|.In the formula, T
0, β
2, P
0, γ, β
3Be respectively pulse half-width, GVD constant, pulse peak power, nonlinear fiber coefficient and third-order dispersion.Realize that the rule that SC effectively produces is: L
D2/ L
NLHigh more, the SC spectrum is wide more; Simultaneously, L
D2/ L
D3Enough little, enter the anomalous dispersion district of optical fiber and reduce the quality of SC spectrum so that the SC spectrum that guarantees institute's broadening is unlikely, and this also is to produce the assurance that good linear is just being warbled in whole SC pulse duration.Determine thus to select the basic standard of SC optical fiber to be: the nonlinear fiber coefficient wants big; The 2nd order chromatic dispersion value is as far as possible little; Values of third-order dispersion is the smaller the better with respect to the 2nd order chromatic dispersion value.We can also see by two top rules: increase 2nd order chromatic dispersion and can suppress third-order dispersion, its cost can be compensated by corresponding increase non linear coefficient.Specific to practical application, the optical fiber that is suitable for the SC generation has two classes: (1) has the Dispersion Flattened Fiber (DFF) of normal dispersion value; (2) has the normal dispersion highly nonlinear optical fiber (HNLF) of big relatively 2nd order chromatic dispersion value.Dispersion Flattened Fiber has two zero-dispersion wavelengths, lays respectively near 1.3 μ m and the 1.6 μ m.Can be implemented in like this that 1.3 μ m～1.6 mum wavelength scope total dispersions are all very little, and chromatic dispersion gradient is also very little.What have high pulse repetition rate (10GHz and more than) the SC spectrum of practical application report to produce at present to adopt mainly is exactly this optical fiber.The advantage of this SC optical fiber is: when pulse was propagated in optical fiber, very little 2nd order chromatic dispersion had also slowed down the speed that peak power descends in the broadening speed that reduces pulse, guaranteed the useful effect of the SPM of leading spectrum widening.Yet this optical fiber realizes that the means of dispersion flattene are to make the waveguide dispersion curve have bigger slope, or its negative dispersion value is steeper with wavelength change, so that 1.3 μ m～1.6 mum wavelength scope inner waveguide chromatic dispersions and material dispersion are offset preferably.Thereby the refraction index profile of this optical fiber is very complicated, and the optical fiber fabrication difficulty of this structure is very big, and unit length costs an arm and a leg.Moreover, proved that the optimum length of the optical fiber of realizing the abundant broadening of spectrum and the evolution of abbe number are inversely proportional to, the length of common required optical fiber is more than 1km.And dispersion values is more little, and the ripple (ripple) that the top of stretched-out spectrum occurs is big more, and the actual fiber lengths that uses can extend with the vibration and the stable amplitude noise of flat top.Nearest research also shows: for the SC optical fiber of DFF formation, because the absolute value of 2nd order chromatic dispersion is minimum, small chromatic dispersion deviation and fluctuation also can greatly reduce the dedicated bandwidth that has of SC spectrum, and this just requires must strictly keep constant in the fiber lengths dispersion parameters of whole burst transmissions.Therefore this optical fiber production precision has a strong impact on the quality that its SC spectrum produces.Under present technological level, relatively the solution of reality is to improve the absolute value of chromatic dispersion.Take all factors into consideration above factor, adopting the HNLF with high normal dispersion is choose reasonable as SC optical fiber to constitute the pulse spectrum stretcher.
The pulse spectrum stretcher structure that the simple HNLF of employing constitutes is very simple: light pulse is after EDFA amplifies, and the HNLF that directly enters the high normal dispersion of length-specific realizes spectrum widening.The exhibition spectral property of this pulse spectrum stretcher is: go into pulse peak power one regularly, fiber lengths is long more, and spectrum widening is wide more, but the broadening degree can significantly reduce; Continue to increase fiber lengths, pulse stretcher, spectrum widening is atomic, and just the envelope shape of spectrum is more smooth.This is because pulse when transmitting in the HNLF of high normal dispersion value, the very fast broadening of pulse meeting, and peak power descends thereupon and causes the SPM effect of leading spectrum widening to weaken rapidly, and after this, the exhibition spectrum almost stops, and chromatic dispersion plays a leading role.As seen, as the HNLF that SC produces, input pulse condition one is regularly effectively opened up spectrum length and is had limiting value, and simple dependence increases HNLF length, the effectively spectrum of stretched pulse.On the other hand, for the pulse of input, under the certain situation of pulse duration, obviously its peak power is high more, and then exhibition spectrum effect is good more.Pulse is amplified by EDFA can improve its peak power, but the effect and the pulse recurrence rate that amplify are inversely proportional to, and for the pulse train of 40GHz, the saturation output power restriction that pulse peak power is subjected to EDFA can not effectively improve.Therefore, the pulse spectrum broadening efficient for the high pulse repetition frequency of 40GHz of the pulse spectrum stretcher that constitutes of the HNLF in the common solution is not high.
Summary of the invention
Technical problem to be solved by this invention is: a kind of 40GHz optical pulse series spectral stretcher device based on highly nonlinear optical fiber is provided, and the pulse spectrum stretcher that constitutes with the HNLF that overcomes in the common solution is for the pulse spectrum broadening efficient problem on the low side of the high pulse repetition frequency of 40GHz.
The technical solution adopted in the present invention is as follows:
Optical pulse series spectral stretcher device based on highly nonlinear optical fiber provided by the invention, its structure is: be provided with the highly nonlinear optical fiber of two sections different lengths, between them welding a standard single-mode fiber.
Based on the optical pulse series spectral stretcher device of highly nonlinear optical fiber, as the broadband coherent source of the 40GHz high pulse repetition frequency of wavelength division multiplexing.
The present invention is a kind of novel pulse spectrum stretcher, compared with prior art has following major advantage:
Pulse train for this high pulse repetition frequency of 40GHz, pulse peak power is amplified under the limited situation, novel pulse spectrum stretcher adopts the chirped pulse compress technique, realized the further effective broadening of pulse spectrum by the spectrum widening efficient that improves HNLF, promptly under the HNLF condition of identical pump pulse input and use equal length, the pulse spectrum broadening can be significantly increased.Compare with the spectrum widening device that adopts one section 150mHNLF, the 10dB spectrum widening can be brought up to about 30nm from 10nm.
Description of drawings
Fig. 1 is the pulse spectrum stretcher schematic diagram that the present invention is based on highly nonlinear optical fiber;
The super continuous spectrums that Fig. 2 realizes for the present invention is as the ultra-short pulse source schematic diagram of multi-wavelength high pulse repetition rate.
Embodiment
The present invention is a kind of novel pulse spectrum stretcher, be specifically related to utilize highly nonlinear optical fiber (HNLF) with high normal dispersion value, constitute 40GHz optical pulse series spectral stretcher device, so that the broadband coherent source as the high pulse repetition frequency of wavelength division multiplexing (WDM) to be provided.Amplify limited pulse train for this pulse peak power of 40GHz, novel pulse spectrum stretcher adopts the chirped pulse compress technique, the generation efficient of the super continuous spectrums by improving this HNLF (Supercontinuum is called for short SC) has realized the significant raising of pulse spectrum broadening.
The structure principle of pulse spectrum stretcher of the present invention is: at first, and according to highly nonlinear optical fiber (HNLF) characteristic of input pulse and use, the length of the monomode fiber that settles the standard (SMF) and two sections HNLF.HNLF length be to determine according to the limiting value of this HNLF spectral effective broadening.The SMF fiber lengths is by the optimum of chirped pulse compensation, and its The optimal compensation point also is the pulse peak power peak.
Secondly, the optical fiber of designated length is carried out welding in regular turn, it is inserted SC produces light path for convenient, can be in the welding of the outer end of two sections HNLF oblique section optical fiber tie jumper, the actual pulse spectrum stretcher structure chart that uses is as shown in Figure 1.
The pulse train of the 40GHz that active mode locking arteries and veins laser ultra-short pulse source (PSL-40-1-TS) produces, its centre wavelength is at 1550nm, pulse duration is 1.2ps, and through high-power EDFA (BT2-C-30-PB-FA), and the average power of pulse train is amplified to about 27dBm.
The invention will be further described below in conjunction with embodiment and accompanying drawing.
The present invention is based on the optical pulse series spectral stretcher device of highly nonlinear optical fiber, constitute by three sections optical fiber, concrete structure as shown in Figure 1: be provided with the highly nonlinear optical fiber 1,3 of different length, between them welding a standard single-mode fiber 2.
The present invention adopts the chirped pulse compress technique, utilizes the combination of highly nonlinear optical fiber 1,3 and standard single-mode fiber 2, realizes the compression and the spectrum widening of 40GHz light pulse.The chirped pulse compress technique is: pump pulse is a highly nonlinear optical fiber 1 by first section HNLF at first, the linearity that the obtains spectrum widening SC pulse of just warbling, the standard single-mode fiber 2 (SMF) that the passes through respective length then compensation compression of warbling, to improve the peak power of pulse once more, entering second section HNLF at last is the further broadening that highly nonlinear optical fiber 3 is realized pulse spectrum.So, the present invention has made full use of the positive chirping characteristics of HNLF favorable linearity, and (2nd order chromatic dispersion is much larger than third-order dispersion, can effectively suppress the third-order dispersion effect), effectively compensate thereby can warble with negative wire among the SMF, the pulse meeting is compressed in the time of compensation, when the compensation of warbling was finished, pulse was compressed into the narrowest, and pulse peak power can improve again.When pulse this moment entered second section HNLF again, the SPM effect effect that is directly proportional with pulse peak power strengthened once more, so spectrum has further obtained broadening thereupon.
The length of above-mentioned highly nonlinear optical fiber 1,3 is respectively 80～150m and 45～85m, perhaps decides according to actual conditions, generally adopts 100,50m is just passable.Can adopt the highly nonlinear optical fiber of being produced by SUMITOMO CHEMICAL company, its main parameter is as follows: non linear coefficient γ=21/km/w, and 1.55 μ m place's losses are 0.53dB/km, abbe number is-12.2ps/km/nm that chromatic dispersion gradient is 0.012ps/km/nm
2
Standard single-mode fiber 2 can adopt and G.652 wait kind optical fiber, and its length is 50～100m, perhaps decides according to actual conditions, generally adopts 70m long just passable.Can adopt the G.652 optical fiber of being produced by optical fiber company of Wuhan Changfei, its major parameter is: non linear coefficient γ=1.34/km/w, and 1.55 μ m place's losses are 0.32dB/km, abbe number is-18ps/km/nm that chromatic dispersion gradient is 0.09ps/km/nm
2
Behind definite good highly nonlinear optical fiber 1,3 and 2 three sections fiber lengths of standard single-mode fiber, cutting optical fibre and welding optic fibre in order, and the optical patchcord connector at highly nonlinear optical fiber 1,3 two ends.Will control the loss of solder joint when the critical process here is the welding of HNLF and G652 optical fiber well, by optimizing the fused fiber splice condition, this loss value can be controlled at 0.1dB even littler.
The present invention can be used as the broadband coherent source of the 40GHz high pulse repetition frequency of wavelength division multiplexing.
The broadening wave-length coverage of spectrum widening device of the present invention can reach 1530～1565nm.
The super continuous spectrums that the present invention realizes is as the ultra-short pulse source schematic diagram of multi-wavelength high pulse repetition rate, as shown in Figure 2.Among the figure: 4. wavelength axis; 5. clock; 6. time shaft; 7. spectrum widening device of the present invention; 8. super continuous spectrums; 9. wavelength axis; 10. wavelength filter; 11. multi wave length illuminating source.
Claims (8)
1. a spectrum widening device is characterized in that the optical pulse series spectral stretcher device based on highly nonlinear optical fiber, and its structure is: be provided with highly nonlinear optical fiber (1), (3) of different length, between them welding a standard single-mode fiber (2).
2. spectrum widening device according to claim 1, it is characterized in that described optical pulse series spectral stretcher device based on highly nonlinear optical fiber, it adopts the chirped pulse compress technique, utilize the combination of highly nonlinear optical fiber (1), (3) and standard single-mode fiber (2), realize the compression of 40GHz light pulse and the amplification of pulse power.
3. spectrum widening device according to claim 1 and 2 is characterized in that described highly nonlinear optical fiber (1), (3), and length is respectively 80～150m and 45～85m.
4. spectrum widening device according to claim 3 is characterized in that described highly nonlinear optical fiber (1), (3), and length is respectively 100,50m.
5. spectrum widening device according to claim 1 and 2 is characterized in that described standard single-mode fiber (2) is an optical fiber G.652, and its length is 50～100m.
6. spectrum widening device according to claim 5, the length that it is characterized in that described standard single-mode fiber (2) is 70m.
7. optical pulse series spectral stretcher device based on highly nonlinear optical fiber is as the broadband coherent source of the 40GHz high pulse repetition frequency of wavelength division multiplexing.
8. spectrum widening device according to claim 7 is characterized in that described spectrum widening device, and its broadening wave-length coverage is 1530～1565nm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB200510018146XA CN100444539C (en) | 2005-01-13 | 2005-01-13 | Optical pulse series spectral stretcher based on high nonlinear optic fibre |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB200510018146XA CN100444539C (en) | 2005-01-13 | 2005-01-13 | Optical pulse series spectral stretcher based on high nonlinear optic fibre |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1645771A true CN1645771A (en) | 2005-07-27 |
| CN100444539C CN100444539C (en) | 2008-12-17 |
Family
ID=34875662
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB200510018146XA Expired - Fee Related CN100444539C (en) | 2005-01-13 | 2005-01-13 | Optical pulse series spectral stretcher based on high nonlinear optic fibre |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100444539C (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107024816A (en) * | 2017-04-21 | 2017-08-08 | 上海理工大学 | Higher order dispersion compensation chirp spectrum widening system |
| CN112152065A (en) * | 2020-09-16 | 2020-12-29 | 飞秒激光研究中心（广州）有限公司 | Laser pulse spectrum broadening device and laser |
| CN113488833A (en) * | 2021-07-07 | 2021-10-08 | 北京交通大学 | Flat optical frequency comb generation device and method |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPWO2002071142A1 (en) * | 2001-03-02 | 2004-07-02 | 財団法人名古屋産業科学研究所 | Broadband optical spectrum generator and pulsed light generator |
| JP4401626B2 (en) * | 2002-07-05 | 2010-01-20 | 富士通株式会社 | Method and apparatus for processing optical signals |
| CN1234031C (en) * | 2003-11-07 | 2005-12-28 | 清华大学 | Device for increasing signal-to-noise ratio of dense wave division multiplex multiple wavelength light source |
-
2005
- 2005-01-13 CN CNB200510018146XA patent/CN100444539C/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107024816A (en) * | 2017-04-21 | 2017-08-08 | 上海理工大学 | Higher order dispersion compensation chirp spectrum widening system |
| CN112152065A (en) * | 2020-09-16 | 2020-12-29 | 飞秒激光研究中心（广州）有限公司 | Laser pulse spectrum broadening device and laser |
| CN116759879A (en) * | 2020-09-16 | 2023-09-15 | 飞秒激光研究中心（广州）有限公司 | Laser pulse spectrum widening device and laser |
| CN113488833A (en) * | 2021-07-07 | 2021-10-08 | 北京交通大学 | Flat optical frequency comb generation device and method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN100444539C (en) | 2008-12-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Giles | Lightwave applications of fiber Bragg gratings | |
| JP5193188B2 (en) | Optical pulse shaper, optical pulse light source, supercontinuum light generator and supercontinuum light generation method | |
| US7486436B1 (en) | All fiber chirped pulse amplification system and method | |
| US20070160092A1 (en) | Broad-band light source | |
| CN1261445A (en) | Modulation instability wavelength converter | |
| US7483614B2 (en) | Optical fiber and optical device using the same | |
| US5754334A (en) | Device for and method of modifying the spectral characteristics of optical signals | |
| JP2002303899A (en) | Light pulse generator | |
| CN111443547B (en) | Multi-wavelength tunable wavelength converter based on forward stimulated Brillouin scattering of optical fiber | |
| Sayed et al. | Symmetrical and post dispersion compensation in WDM optical communication systems | |
| Mustafa et al. | Dispersion compensation analysis of optical fiber link using cascaded apodized FBGs hybrid with maximum time division multiplexing transmission technique | |
| US20020164135A1 (en) | Optical pulse waveform conversion | |
| CN100444539C (en) | Optical pulse series spectral stretcher based on high nonlinear optic fibre | |
| JP4107072B2 (en) | Optical module and optical transmission system | |
| US6865328B2 (en) | Positive dispersion optical fiber | |
| CN1556561A (en) | Wave length tunable narrow wire width, high signal noise ratio single polarization ring cavity full optical fiber laser | |
| JP5408313B2 (en) | Optical device, wavelength conversion method, and optical fiber suitable therefor | |
| Quetel et al. | Chromatic dispersion compensation by apodised Bragg gratings within controlled tapered fibers | |
| JP5261968B2 (en) | Optical device, wavelength conversion method, and optical fiber suitable therefor | |
| US7079737B1 (en) | Devices and methods for dynamic dispersion compensation | |
| CN1234031C (en) | Device for increasing signal-to-noise ratio of dense wave division multiplex multiple wavelength light source | |
| Kaushal et al. | Group-velocity dispersion compensation of telecom data signals using compact discrete phase filters in silicon | |
| KR100326151B1 (en) | Raman fiber amplifier with enhanced signal-to-noise ratio and method for the use thereof | |
| Chow et al. | All-optical pulse compression and reshaping by spectral filtering from self-phase modulation in a nonlinear photonic crystal fiber | |
| Turitsyn et al. | Solitary waves in nonlinear dispersive systems with zero average dispersion |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20081217 Termination date: 20110113 |