Development and Ch Characterization of of Op Optical Fol ollow - PowerPoint PPT Presentation

Development and Ch Characterization of of Op Optical Fol ollow ower r Se Servo rvo for or Photon Ca Calibrator Bin-Hua Hsieh Ayako Hagiwara A , Sadakazu Haino B , Kunihiko Hasegawa, Yuki Inoue A, B , Takaaki Kajita, Nobuyuki Kanda C , Nobuhiro Kimura A, D , Takahiro Miyamoto, Iwao Murakami A , Yoshikazu Namai A , Takaharu Shishido A , Toshikazu Suzuki, Shinichi Terashima A , Takayuki Tomoru A, D , Ayako Ueda A , Tomohiro Yamada, Takahiro Yamamoto, Takaaki Yokozawa C ICRR, KEK A , Academia Sinica B , Osaka City Univ. C , Sokendai D Sep 13 rd , 2017 2017 JPS Autumn meeting @ Utsunomiya University 1

Ou Outline l Introduction l Beam Waist Measurement l Mode Matching l AOM Modulation l Optical Follower Servo l Future Work & Summary Sep 13 rd , 2017 2017 JPS Autumn meeting @ Utsunomiya University 2

Ph Phot oton on Calibrator or Sep 13 rd , 2017 2017 JPS Autumn meeting @ Utsunomiya University 3

Tr Transmitter Mo Modul dule Laser Power: 20W OFSPD Sep 13 rd , 2017 2017 JPS Autumn meeting @ Utsunomiya University 4

Mo Moti tivati tion of using High Po Power Laser For the same mirror displacement, we need high power laser to modulate mirror in high frequency 1.To reconstruct h(t) signal at high frequency 2.Gravitational waveform injection test Sep 13 rd , 2017 2017 JPS Autumn meeting @ Utsunomiya University 5

Laser characterization AOM Modulation Optical Follower Servo Sep 13 rd , 2017 2017 JPS Autumn meeting @ Utsunomiya University 6

� Be Beam Waist Measu surement The beam width requirement of AOM is 250 𝜈 m, so we need to measure the beam spot size of our laser and calculate the beam waist. We used the Gaussian beam spot size equation to fit the data. z: Distance from the laser + 𝜇𝑨 𝜕 0 : Beam waist 𝜕 𝑨 = 𝜕 0 1 + + 𝜌𝜕 * 𝜇 : Beam wavelength Sep 13 rd , 2017 2017 JPS Autumn meeting @ Utsunomiya University 7

Beam Wa Be Waist Measurement Beam waist Beam waist 2500 Horizontal axis Vertical axis 2000 m] 1500 µ Sopt size [ Beam width typical value: 250 𝜈 m 1000 Beam waist( 𝜈 m) Position(mm) H 260 ± 1 -1 ± 9 500 V 253 ± 1 4 ± 9 0 0 500 1000 1500 2000 Distance from laser [mm] Sep 13 rd , 2017 2017 JPS Autumn meeting @ Utsunomiya University 8

Mo Mode Ma Matching l Beam waist Requirements ◦ AOM:250 𝜈 m ◦ Sapphire Mirror:~3500 𝜈 m l Need to decide the position of lenses and AOM Sep 13 rd , 2017 2017 JPS Autumn meeting @ Utsunomiya University 9

Mode Ma Mo Matching 1 st Mode Matching (AOM) 100 300 1 positive lens Requirements: W 0 (beam spot size)= 250 𝜈 m 400 Z 0 (position)= 635~ 915mm 425 Lens Shifting Range= 150~400mm 280 470 600 2 nd Mode Matching (ETM 425 Mirror) 375 1 positive and 1 negative lens 175 Requirements: 455 W 0 = 3500 𝜈 m 110 Z 0 = 36~40 m Shifting Range=2095~2405mm 350 Sep 13 rd , 2017 2017 JPS Autumn meeting @ Utsunomiya University 10

Mode Ma Mo Matching 2 nd Mode Matching (Mirror) 1 st Mode Matching (AOM) Negative Lens Positive Lens Positive Lens f= -57.38mm f= 143.22mm W 0 = 250 𝜈 m f= 286.46mm z=2136mm z=2226mm Z 0 = 710 mm z=361mm W 0 = 3501 𝜈 m Z 0 = 39.93 m Sep 13 rd , 2017 2017 JPS Autumn meeting @ Utsunomiya University 11

Beam Be m waist with lens s Path 1 M2H=1.035,M2V=1.09 M2H=1.035,M2V=1.09 2500 Horizontal axis Beam waist( 𝜈 m) Vertical axis H 261 ± 5 2000 V 265 ± 5 m] 1500 µ Spot size [ 1000 500 0 0 500 1000 1500 2000 Distance from laser [mm] Sep 13 rd , 2017 2017 JPS Autumn meeting @ Utsunomiya University 12

Beam Be m waist with lens s Pa Path 2 M2H=1.06,M2V=1.13 M2H=1.06,M2V=1.13 2500 Horizontal axis Beam waist( 𝜈 m) Vertical axis H 254 ± 6 2000 V 255 ± 6 m] 1500 µ Spot size [ 1000 500 0 0 500 1000 1500 2000 Distance from laser [mm] Sep 13 rd , 2017 2017 JPS Autumn meeting @ Utsunomiya University 13

Comp Co mpari riso son Path 1 Path 2 M 2 H 0.97 ± 0.01 0.98 ± 0.01 M 2 : Beam quality factor V 1.02 ± 0.01 1.04 ± 0.02 261.24 ± 5.41 254.06 ± 6.48 W 0 ( 𝜈 m) H W 0 : Beam waist 265.42 ± 5.40 254.95 ± 6.32 V Z 0 (mm) H 879.14 ± 6.73 896.73 ± 7.58 Z 0 : Beam waist position V 884.56 ± 6.43 897.94 ± 7.09 X Y M 2 H 0.97 ± 0.01 1.00 ± 0.01 V 1.02 ± 0.01 0.98 ± 0.01 261.24 ± 5.41 261.63 ± 4.42 W 0 ( 𝜈 m) H 265.42 ± 5.40 261.87 ± 4.46 V Z 0 (mm) H 879.14 ± 6.73 849.90 ± 6.09 V 884.56 ± 6.43 844.89 ± 6.31 Sep 13 rd , 2017 2017 JPS Autumn meeting @ Utsunomiya University 14

AO AOM Modulation Frequency: 120 Hz Laser Lens AOM Sep 13 rd , 2017 2017 JPS Autumn meeting @ Utsunomiya University 15

Op Optical Fol ollower Servo o (OF OFS) Purpose: Reduce the Relative Power Noise (RPN) of the laser Reduce the harmonic noise of AOM Optical Follower Servo RPN Requirement Sep 13 rd , 2017 2017 JPS Autumn meeting @ Utsunomiya University 16

Re Relative Power Noise Δ𝑀 𝑔 = 2Δ𝑄 cos 𝜄 𝑁(2𝜌𝑔) + < 1 1 10 Δℎ 𝑔 𝑀 𝑑 Strain sensitivity curve of KAGRA Force Transfer function ⟹ Δ𝑄 < 𝑑𝑁(2𝜌𝑔) + Δℎ 𝑔 𝑀 20 cos 𝜄 R𝑄𝑂 ≡ Δ𝑄 𝑄 Sep 13 rd , 2017 2017 JPS Autumn meeting @ Utsunomiya University 17

Future Work 1. Measure the Relative Power Noise with 20W power 2. Measure the performance of Optical Follower Servo (OFS) Sep 13 rd , 2017 2017 JPS Autumn meeting @ Utsunomiya University 18

Su Summar ary l We used 20W high power laser in our Tx module. l The beam waist of our laser is 260 𝜈 m. l We did mode matching and decided the type and the position of the lenses and the position of AOM, and measured beam profile for two paths l We modulated the AOM with 120 Hz sine wave. l We calculated the requirements of the RPN and built a OFS chassis to reduce the noise. Sep 13 rd , 2017 2017 JPS Autumn meeting @ Utsunomiya University 19

Thank for your listening! The end Sep 13 rd , 2017 2017 JPS Autumn meeting @ Utsunomiya University 20