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Medhu Ghat
Jul 15, 2019
Nov 26, 2017
MOPA LASER
Optics
Master Oscillator Power Amplifier |
Acronym: MOPA
Definition: a laser system consisting of a seed laser and a laser amplifier for boosting the output power
German: Laser-/Verstärker-Kombination
The term master oscillator power amplifier(MOPA) refers to a configuration consisting of amaster laser (or seed laser) and an opticalamplifier to boost the output power. A special case is the master oscillator fiber amplifier(MOFA), where the power amplifier is a fiber device. In other cases, a MOPA may consist of asolid-state bulk laser and a bulk amplifier, or of a tunable external-cavity diode laser andsemiconductor optical amplifier.
Although a MOPA configuration is in principle more complex than a laser which directly produces the required output power, the MOPA concept can have certain advantages:
- With a MOPA instead of a laser, it can be easier to reach the required performance e.g. in terms of linewidth, wavelength tuning range, beam quality or pulse duration if the required power is very high. This is because various performance aspects are decoupled from the generation of high powers. This gives extra flexibility, e.g. when a gain-switched laser diode is used as a seed laser. Note also that it can be advantageous to avoid the presence of additional optical components such as wavelength tuning elements in a high-power laser resonator; with a MOPA architecture, one can place these in the oscillator, where they do not have to withstand high optical intensities, do not spoil the power efficiency, etc.
- The same aspects apply to other kinds ofmodulation, e.g. intensity or phase modulation: it may be advantageous to modulate the low-power seed laser, or to use an optical modulator between seed laser and power amplifier, rather than to modulate a high-power device directly. Slower power modulation may be done by adjusting the amplifier's pump power, without significantly affecting e.g. the obtained pulse duration or wavelength.
- The combination of an existing laser with an existing amplifier (or an amplifier chain) may be simpler than developing a new laser with higher output power.
- The optical intensities are lower in an amplifier, compared with the intracavity intensities in a laser.
However, the MOPA approach can also have disadvantages:
- The complexity of the setup is higher.
- The wall-plug efficiency is often lower. However, it may also be higher, e.g. if that approach allows to remove lossy optical elements from the high-power stage.
- The resulting laser noise tends to be higher, since an amplified source can not reach the shot noise level (→ amplifier noise). Effects of drifts of the seed power may be suppressed, however, if the amplifier is operated in a stronglysaturated regime.
- A MOPA can be sensitive to back-reflections, which are amplified again before entering the master laser. This feedback sensitivity can often be cured only by placing a Faraday isolator behind the amplifier. Particularly for high-powerpulsed devices, this can introduce serious limitations.
MOPA architectures are also used for pulsedlaser sources. In that case, the amplifier may be used as a reservoir of energy. If a pulse from the seed laser extracts a significant fraction of the stored energy, the effect of gain saturationis relevant: the amplifier gain drops during the pulse. This can lead to a deformation of the temporal pulse shape. In some cases, the pulse shape from the seed source is tailored so as to obtain the desired pulse shape and application
Apr 9, 2017
Feb 10, 2015
Election
Now as Bihar elections are going to come so be ready for vote this time and make your govt. to in this time so that you can get ace of development.Because your vote is important to make your party win.
Dec 10, 2014
ICC World Cup 2015
Its coming fast Feb 14 2015 - Mar 29 2015  Teams: New zealand, Sri Lanka, Australia, England, South Africa, Pakistan, India, Zimbabwe, Ireland, West Indies, Bangladesh, Afghanistan, Scotland, United Arab Emirates.Zim has loss the zim Great battel is going on .. India won by 76 runs
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| Date | Match Details | Time | Venue | D/N | |||
| GMT | IST | Your Time | Ground | City | |||
| Feb 14 - Sat | Australia vs England, 2nd Match, Pool A | 03:30 | 09:00 | 09:00 | Melbourne Cricket Ground | Melbourne |  |
| Feb 14 - Sat | New Zealand vs Sri Lanka, 1st Match, Pool A | 22:00 Feb 13 | 03:30 (Feb 14) | 03:30
(Feb 14)
| Hagley Oval | Christchurch |  |
| Feb 15 - Sun | South Africa vs Zimbabwe, 3rd Match, Pool B | 01:00 | 06:30 | 06:30 | Seddon Park | Hamilton | |
| Feb 15 - Sun | India vs Pakistan, 4th Match, Pool B | 03:30 | 09:00 | 09:00 | Adelaide Oval | Adelaide | |
| Feb 16 - Mon | Ireland vs West Indies, 5th Match, Pool B | 22:00 Feb 15 | 03:30 (Feb 16) | 03:30
(Feb 16)
| Saxton Oval | Nelson | |
| Feb 17 - Tue | New Zealand vs Scotland, 6th Match, Pool A | 22:00 Feb 16 | 03:30 (Feb 17) | 03:30
(Feb 17)
| University Oval | Dunedin | |
| Feb 18 - Wed | Bangladesh vs Afghanistan, 7th Match, Pool A | 03:30 | 09:00 | 09:00 | Manuka Oval | Canberra | |
| Feb 19 - Thu | United Arab Emirates vs Zimbabwe, 8th Match, Pool B | 22:00 Feb 18 | 03:30 (Feb 19) | 03:30
(Feb 19)
| Saxton Oval | Nelson | |
| Feb 20 - Fri | New Zealand vs England, 9th Match, Pool A | 01:00 | 06:30 | 06:30 | Westpac Stadium | Wellington | |
| Feb 21 - Sat | Australia vs Bangladesh, 11th Match, Pool A | 03:30 | 09:00 | 09:00 | Brisbane Cricket Ground | Woolloongabba, Brisbane | |
| Feb 21 - Sat | Pakistan vs West Indies, 10th Match, Pool B | 22:00 Feb 20 | 03:30 (Feb 21) | 03:30
(Feb 21)
| Hagley Oval | Christchurch | |
| Feb 22 - Sun | India vs South Africa, 13th Match, Pool B | 03:30 | 09:00 | 09:00 | Melbourne Cricket Ground | Melbourne | |
| Feb 22 - Sun | Afghanistan vs Sri Lanka, 12th Match, Pool A | 22:00 Feb 21 | 03:30 (Feb 22) | 03:30
(Feb 22)
| University Oval | Dunedin | |
| Feb 23 - Mon | England vs Scotland, 14th Match, Pool A | 22:00 Feb 22 | 03:30 (Feb 23) | 03:30
(Feb 23)
| Hagley Oval | Christchurch | |
| Feb 24 - Tue | West Indies vs Zimbabwe, 15th Match, Pool B | 03:30 | 09:00 | 09:00 | Manuka Oval | Canberra | |
| Feb 25 - Wed | Ireland vs United Arab Emirates, 16th Match, Pool B | 03:30 | 09:00 | 09:00 | Brisbane Cricket Ground | Woolloongabba, Brisbane | |
| Feb 26 - Thu | Bangladesh vs Sri Lanka, 18th Match, Pool A | 03:30 | 09:00 | 09:00 | Melbourne Cricket Ground | Melbourne | |
| Feb 26 - Thu | Afghanistan vs Scotland, 17th Match, Pool A | 22:00 Feb 25 | 03:30 (Feb 26) | 03:30
(Feb 26)
| University Oval | Dunedin | |
| Feb 27 - Fri | South Africa vs West Indies, 19th Match, Pool B | 03:30 | 09:00 | 09:00 | Sydney Cricket Ground | Sydney | |
| Feb 28 - Sat | New Zealand vs Australia, 21st Match, Pool A | 01:00 | 06:30 | 06:30 | Eden Park | Auckland | |
| Feb 28 - Sat | India vs United Arab Emirates, 20th Match, Pool B | 06:30 | 12:00 | 12:00 | W.A.C.A. Ground | Perth | |
| Mar 01 - Sun | Pakistan vs Zimbabwe, 23rd Match, Pool B | 03:30 | 09:00 | 09:00 | Brisbane Cricket Ground | Woolloongabba, Brisbane | |
| Mar 01 - Sun | England vs Sri Lanka, 22nd Match, Pool A | 22:00 Feb 28 | 03:30 (Mar 1) | 03:30
(Mar 1)
| Westpac Stadium | Wellington | |
| Mar 03 - Tue | Ireland vs South Africa, 24th Match, Pool B | 03:30 | 09:00 | 09:00 | Manuka Oval | Canberra | |
| Mar 04 - Wed | Pakistan vs United Arab Emirates, 25th Match, Pool B | 01:00 | 06:30 | 06:30 | McLean Park | Napier | |
| Mar 04 - Wed | Australia vs Afghanistan, 26th Match, Pool A | 06:30 | 12:00 | 12:00 | W.A.C.A. Ground | Perth | |
| Mar 05 - Thu | Bangladesh vs Scotland, 27th Match, Pool A | 22:00 Mar 4 | 03:30 (Mar 5) | 03:30
(Mar 5)
| Saxton Oval | Nelson | |
| Mar 06 - Fri | India vs West Indies, 28th Match, Pool B | 06:30 | 12:00 | 12:00 | W.A.C.A. Ground | Perth | |
| Mar 07 - Sat | Pakistan vs South Africa, 29th Match, Pool B | 01:00 | 06:30 | 06:30 | Eden Park | Auckland | |
| Mar 07 - Sat | Ireland vs Zimbabwe, 30th Match, Pool B | 03:30 | 09:00 | 09:00 | Bellerive Oval | Hobart | |
| Mar 08 - Sun | Australia vs Sri Lanka, 32nd Match, Pool A | 03:30 | 09:00 | 09:00 | Sydney Cricket Ground | Sydney | |
| Mar 08 - Sun | New Zealand vs Afghanistan, 31st Match, Pool A | 22:00 Mar 7 | 02:30 (Mar 8) | 02:30
(Mar 8)
| McLean Park | Napier | |
| Mar 09 - Mon | England vs Bangladesh, 33rd Match, Pool A | 03:30 | 09:00 | 09:00 | Adelaide Oval | Adelaide | |
| Mar 10 - Tue | India vs Ireland, 34th Match, Pool B | 01:00 | 06:30 | 06:30 | Seddon Park | Hamilton | |
| Mar 11 - Wed | Sri Lanka vs Scotland, 35th Match, Pool A | 03:30 | 09:00 | 09:00 | Bellerive Oval | Hobart | |
| Mar 12 - Thu | South Africa vs United Arab Emirates, 36th Match, Pool B | 01:00 | 06:30 | 06:30 | Westpac Stadium | Wellington | |
| Mar 13 - Fri | New Zealand vs Bangladesh, 37th Match, Pool A | 01:00 | 06:30 | 06:30 | Seddon Park | Hamilton | |
| Mar 13 - Fri | Afghanistan vs England, 38th Match, Pool A | 03:30 | 09:00 | 09:00 | Sydney Cricket Ground | Sydney | |
| Mar 14 - Sat | India vs Zimbabwe, 39th Match, Pool B | 01:00 | 06:30 | 06:30 | Eden Park | Auckland | |
| Mar 14 - Sat | Australia vs Scotland, 40th Match, Pool A | 03:30 | 09:00 | 09:00 | Bellerive Oval | Hobart | |
| Mar 15 - Sun | Ireland vs Pakistan, 42nd Match, Pool B | 03:30 | 09:00 | 09:00 | Adelaide Oval | Adelaide | |
| Mar 15 - Sun | West Indies vs United Arab Emirates, 41st Match, Pool B | 22:00 Mar 14 | 03:30 (Mar 15) | 03:30
(Mar 15)
| McLean Park | Napier | |
| Mar 18 - Wed | TBC vs TBC, 1st Quarter-Final (A1 v B4) | 03:30 | 09:00 | 09:00 | Sydney Cricket Ground | Sydney | |
| Mar 19 - Thu | TBC vs TBC, 2nd Quarter-Final (A2 v B3) | 03:30 | 09:00 | 09:00 | Melbourne Cricket Ground | Melbourne | |
| Mar 20 - Fri | TBC vs TBC, 3rd Quarter-Final (A3 v B2) | 03:30 | 09:00 | 09:00 | Adelaide Oval | Adelaide | |
| Mar 21 - Sat | TBC vs TBC, 4th Quarter-Final (A4 v B1) | 01:00 | 06:30 | 06:30 | Westpac Stadium | Wellington | |
| Mar 24 - Tue | TBC vs TBC, 1st Semi-Final | 01:00 | 06:30 | 06:30 | Eden Park | Auckland | |
| Mar 26 - Thu | TBC vs TBC, 2nd Semi-Final | 03:30 | 09:00 | 09:00 | Sydney Cricket Ground | Sydney | |
| Mar 29 - Sun | TBC vs TBC, Final | 03:30 | 09:00 | 09:00 | Melbourne Cricket Ground | Melbourne | |
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