The Input Optics for iKAGRA Masayuki Nakano 2014/12/19 Japan-Korea - - PowerPoint PPT Presentation

▶
the input optics for ikagra
SMART_READER_LITE
LIVE PREVIEW

The Input Optics for iKAGRA Masayuki Nakano 2014/12/19 Japan-Korea - - PowerPoint PPT Presentation

Oct 20, 2023 104 likes •418 views

2014/12/19 Japan-Korea Workshop @ Toyama Univ. 1 The Input Optics for iKAGRA Masayuki Nakano 2014/12/19 Japan-Korea Workshop @ Toyama Univ. 2 Contents Background Overview of iKAGRA input optics Summary of PSL test in ICRR IOO

slide-1
SLIDE 1

Japan-Korea Workshop @ Toyama Univ. 2014/12/19

Masayuki Nakano

1

The Input Optics for iKAGRA

slide-2
SLIDE 2

Japan-Korea Workshop @ Toyama Univ. 2014/12/19 2

Contents

  • Background
  • Overview of iKAGRA input optics
  • Summary of PSL test in ICRR
  • IOO Installation in the KAGRA tunnel
  • Plans
slide-3
SLIDE 3

Japan-Korea Workshop @ Toyama Univ. 2014/12/19 3

Contents

  • Background
  • Overview of iKAGRA input optics
  • Summary of PSL test in ICRR
  • IOO Installation in the KAGRA tunnel
  • Plans
slide-4
SLIDE 4

Japan-Korea Workshop @ Toyama Univ. 2014/12/19 4

Background

  • Configuration

✓3 km Fabry Perot Michelson Interferometer

  • Laser Power

✓2W

  • Purpose

✓To gain experience in operating a large

interferometer

We are developing the input optics for iKAGRA. iKAGRA specifications are below.

  • Provide a laser beam stable enough for locking the Fabry-Perot

Michelson Interferometer stably.

✓Frequency stability ✓Reduction of the beam jitter ✓Mode matching

Objectives of Input Optics

slide-5
SLIDE 5

Japan-Korea Workshop @ Toyama Univ. 2014/12/19 5

Contents

  • Background
  • Overview of iKAGRA input optics
  • Summary of PSL test in ICRR
  • IOO Installation in the KAGRA tunnel
  • Plans
slide-6
SLIDE 6

Japan-Korea Workshop @ Toyama Univ. 2014/12/19 6

Overview of iKAGRA input optics

  • In-air optics (In a clean room)

✓A Laser Source ✓EOMs for IMC and MIF control ✓Steering mirrors (SMs) for align the beam ✓The frequency stabilization system with FRC ✓IMC mode matching lenses

  • In-vacuum optics

✓53 m long Input Mode Cleaner (IMC) ✓A vacuum compatible high power faraday isolator ✓An Input Mode Matching Telescope

A Clean room

slide-7
SLIDE 7

Japan-Korea Workshop @ Toyama Univ. 2014/12/19 7

Pre-Stabilized Laser (PSL)

  • Laser Source

✓A monolithic Nd:YAG crystal NPRO (Non-Planar Ring Oscillator)

laser.

✓The power is 2 W

Fig.2 Pre-Stabilized Laser

  • Pre-mode cleaner (PMC)

✓The cavity length will be controlled with a PZT on the end mirror by

Pound-Driver Hall signal.

✓40 cm long triangular cavity.

slide-8
SLIDE 8

Japan-Korea Workshop @ Toyama Univ. 2014/12/19 8

Pre-Stabilized Laser (PSL)

  • Electro-optic Modulators (EOMs)

✓Providing the phase modulations for each cavity length control

  • EOM1 : For PMC
  • EOM2 : For FRC and IMC
  • EOM3 : For main interferometer
  • Broadband EOM : For frequency stabilization

Fig.2 Pre-Stabilized Laser

  • Fiber Ring Cavity (FRC)

✓Used for frequency stabilization as a reference cavity.

slide-9
SLIDE 9

Japan-Korea Workshop @ Toyama Univ. 2014/12/19 9

IMC, IFI, IMMT

  • Input Mode Cleaner (IMC)
  • A triangular cavity with suspended mirrors.
  • Round trip length is 53 m, Finesse is 500, FSR is 5.625 MHz
  • Use the Wave Front Sensing technique for alignment control
  • Input Faraday Isolator (IFI)

✓Vacuum compatible high isolation ratio. ✓We don’t have to suspend it in the

sense of phase noise caused by back scattered light

✓We ordered to the Florida University.

  • Mode Matching Telescope

✓We don’t need any curved mirrors or lenses for mode

matching for the FPMI.

✓We just use flat mirrors for the mode matching telescope.

slide-10
SLIDE 10

Japan-Korea Workshop @ Toyama Univ. 2014/12/19 10

Contents

  • Background
  • Overview of iKAGRA input optics
  • Summary of PSL test in ICRR
  • IOO Installation in the KAGRA tunnel
  • Plans
slide-11
SLIDE 11

Japan-Korea Workshop @ Toyama Univ. 2014/12/19 11

Pre-Mode Cleaner

✓UGF:4.2kHz ✓The lock itself is stable, but

the dynamic range of the PZT is not large enough.

✓We have to make it larger

somehow (change PZT, temperature control, etc.)

✓cavity length : 40 cm ✓The cavity frequency following to

the laser frequency by the PDH

  • control. An actuator is a PZT

attached on the end mirror.

slide-12
SLIDE 12

Japan-Korea Workshop @ Toyama Univ. 2014/12/19 12

Fiber Ring Cavity (FRC)

  • Ref. “All-single-mode fiber resonator”, L.F. Stokes, et al., Opt. Lett. 7, 288 (1982).

1 2 3 4

slide-13
SLIDE 13

Japan-Korea Workshop @ Toyama Univ. 2014/12/19 13

FRC Control

✓UGF:10kHz ✓Up to now, the broadband EOM

haven't been installed yet. UGF might become faster after installing

✓The lock is not stable enough.

(At most 2 hours).

✓cavity length : 5.3m ✓The laser frequency follows the

cavity frequency of FRC with the PDH control. The actuators are laser temperature, laser PZT, broadband EOM.

slide-14
SLIDE 14

Japan-Korea Workshop @ Toyama Univ. 2014/12/19

  • We tested the frequency stabilization system with

FRC

  • We used the PMC feedback signal as the frequency

sensor.

Frequency Stabilization System(FSS) by FRC

14

✓ With FFS, laser frequency become more stable by factor of 2 ✓ You can see the large noise around 1 kHz and 50 Hz HAM noise. The frequency stability would improve by hunting these noises.

slide-15
SLIDE 15

Japan-Korea Workshop @ Toyama Univ. 2014/12/19 15

Contents

  • Background
  • Overview of iKAGRA input optics
  • Summary of PSL test in ICRR
  • IOO Installation in the KAGRA tunnel
  • Plans
slide-16
SLIDE 16

Japan-Korea Workshop @ Toyama Univ. 2014/12/19

  • The Laser room is cleaned up so closely.
  • We wear a clean suit in the laser room

Laser room

16

slide-17
SLIDE 17

Japan-Korea Workshop @ Toyama Univ. 2014/12/19

PSL table

17

96 90 80 70 60 50 40 30 20 10 1 96 90 80 70 60 50 40 30 20 10 1 Laser Iris λ/4 No.1 λ/2 No.1 l1 BS1 IS PBS l2 λ/2 No.2 l3 EOM 15MHz M1 λ/2 No.3 M2 M3 ND Filter PD 1 λ/2 No.4 EOM Broadband PMC M4 l4 EOM 15,25MHz λ/2 No.5 BS2 M5 M6 Collimator lens λ/4 No.2 Fiber IN Fiber OUT l5 M7 PD2 M9 M8 M10 M13 PD3 l7 f=200mm l6 f=400mm M11 M12 l8 f=600mm M13 FRC

Table layout for iKAGRA

2014.12.01

Written by Kataoka (Tokyo Tech)

slide-18
SLIDE 18

Japan-Korea Workshop @ Toyama Univ. 2014/12/19

  • The PMC is locked for 27 hours.
  • Unfortunately, the temperature stability in the room is not

so good as our expectation. That means we have to increase the dynamic range of the control.

PSL table

18

slide-19
SLIDE 19

Japan-Korea Workshop @ Toyama Univ. 2014/12/19

  • The Faraday isolator is under assembling on the PSL

table.

Faraday Isolator

19

slide-20
SLIDE 20

Japan-Korea Workshop @ Toyama Univ. 2014/12/19

  • The suspensions are assembled in NAOJ.
  • The VIS and IOO team starts the installing the

suspensions into vacuum chambers.

Input Mode Cleaner

20

slide-21
SLIDE 21

Japan-Korea Workshop @ Toyama Univ. 2014/12/19 21

Contents

  • Background
  • Overview of iKAGRA input optics
  • Summary of PSL test in ICRR
  • IOO Installation in the KAGRA tunnel
  • Plans
slide-22
SLIDE 22

Japan-Korea Workshop @ Toyama Univ. 2014/12/19

  • Finish the construction of the PSL table
  • Installations of EOMs, FRC, mode matching lenses and

so on.

  • Initial alignment of the beam to the IMC.
  • Improvement of the PMC dynamic range
  • Finish the assembling of IFI
  • Finish the installation of IMC suspensions
  • IMC locking.

Plans

22

slide-23
SLIDE 23

Japan-Korea Workshop @ Toyama Univ. 2014/12/19

End

23

slide-24
SLIDE 24

Japan-Korea Workshop @ Toyama Univ. 2014/12/19

FRC In-loop noise

24

slide-25
SLIDE 25

Japan-Korea Workshop @ Toyama Univ. 2014/12/19

Shape triangular Spacer Invar Mirror Curvature 300 mm Round-trip length 40 cm FSR 768.75 MHz Finesse 230(p) Transmissivity 43%(p) UGF ~4 kHz PZT resonant frequency 9.3 kHz

PMC parameters

25

slide-26
SLIDE 26

Japan-Korea Workshop @ Toyama Univ. 2014/12/19

Gooch & Housego SM Coupler (99.9 % : 0.1 %)

3rd Fiber Ring Cavity Length: 5.8 m fFSR = 35 MHz Δν = 80 kHz Finesse = 540 Contrast: 27 %

Reducing line-width 3times

FRC fabrication: Final design
 for iKAGRA

26

slide-27
SLIDE 27

Japan-Korea Workshop @ Toyama Univ. 2014/12/19

PDH signal

27

slide-28
SLIDE 28

Japan-Korea Workshop @ Toyama Univ. 2014/12/19

The Particle Number

28

Outside

Inside

slide-29
SLIDE 29

Japan-Korea Workshop @ Toyama Univ. 2014/12/19

dirty water inside the room

29

slide-30
SLIDE 30

Japan-Korea Workshop @ Toyama Univ. 2014/12/19

  • The frequency noise stabilization servo will be a multiple loop system.

Frequency Stabilization Servo Topology

  • Using the Fiber Ring Cavity as a reference cavity

✓FRC is easy to use and the alignment is stable.

  • This system will be tested at ICRR.

Frequency Stabilization

30