1. Laser system for LCGT
Norikatsu MIO

2. Power requirement for LGCT laser
50 %
150 W
75 W
780 W
Laser
G=11

3. Laser system for LCGT 150W Output： Injection locking + MOPA
Explain why we need 150 W (what determines the output power?)
Explain quickly (except essential parts)
Emphasize the completed part?

4. Design concept Injection-locked laser: Stable optical mode
Power amplifier: Easy operation, Cascadable for higher power operation
Frequency control element
Intensity control element

5. Injection locked laser
Maser laser：２-W NPRO
Innolight Mephisto
Slave：100-W ring laser
Laser module：Mitsubishi
Resonator and Controller：U-Tokyo

6. Laser module （Mitsubishi）
Diffusive reflector +LD
Two rods and rotator

7. Slave laser
Ring laser with two laser modules

8. Output power of the slave laser
１２１W by bidirectional oscillation

9. 100-W Power laser
Injection locking with 2-W master laser (NPRO)

10. Realization of single frequency oscillation
Scanning Fabry-Perot output
Free
100-W Single
Frequency oscillation
by injection locking
Injection
Locking

11. Long term stability
Continuous operation for more than 6 hours

12. MOPA and intensity stabilization (test bench)
Master
NPRO FR
Amplifier

13. Intensity stabilization performance
Unity Gain freq.
30kHz
Loop Gain
at 100 Hz
100db

14. Ongoing experiments Frequency stabilization of the 100-W laser.
EOM test for high-power laser light.
MgO-doped Stoichiometric LiNbO3
Final stage amplifier (50W) will be tested soon.

15. Frequency stabilization experiment
Triangular reference cavity (Dn=152kHz)
Transmission intensity curve
Feedback system
is being developed

16. Summary Basic components for the LCGT laser have been completed.
100-W single frequency operation has been achieved.
Wide range intensity control has been done by the current-shunt method.
Further experiments for frequency and intensity control are being performed.