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 * EOM: Qubig xxxxxx (ready)  * EOM: Qubig EO-T38M3-VIS (ready)

Arm Length Stabilization System

  • Wiki for ALS (Arm Length Stabilization; Auxiliary Lock System), a.k.a green lock system

ALS Configuration

To Do

  • optical layout of PR2/SR2 chambers, POP/POS table
  • select AOM and AOM driver
    • DONE
  • fix green fiber specs, including how to do the laying
  • fiber collimators for green
  • green fiber after EOM/AOM or before EOM/AOM
    • Not much difference from noise, cable length point of view.
    • Alignment jitter noise from AOM will be less if fiber comes after AOM. So, let it so.
  • fiber for PLL beat or not
    • DECIDED not to use fiber for PLL (Mar 5, 2018)
  • where to put frequency offset: PLL or arm length
  • more detailed noisebudget
  • initial alignment planning
  • comm/diff servo topology
    • necessity of summing node for common mode servo (LIGO-D1300782)

      • first, try with digital switch and decide (Feb 6, 2018)
  • lock acquisition scheme

List of Items

Electronics

Opto-electronics

  • Broadband PD for PLL Newport 818-BB-21A (1.2 GHz bandwidth)

  • Resonant PD for green PDH JGW-D1201280

  • AOM G&H 3080-125 (80MHz) and AOM driver G&H 1075FM-1 (1W, 5MHz BW). (ordered)

  • EOM: Qubig EO-T38M3-VIS (ready)

  • QPD for green beam pointing? (Use Oplev QPD?)
  • Picomotor mount? (ordered)

Optics

  • Faraday isolator Thorlabs IO-5-532-HP (ready)

  • Periscopes Thorlabs Ø1.5inch Post Assembly (ready)

  • Dichroic mirror for periscopes: LEO DRX-1064/532-45P-UF-2038 (ready: 8pcs(2 each for POP/POS/TRX/TRY))
  • Harmonic splitter: LEO LWP-45-R532-T1064-UF-2038 (ready: 8pcs(1 each for POP/POS/TRX/TRY, 4 spares))
  • Dichroic mirror in-vac: Sigma TFVMQ-50.8C10-20-W1D-532/1064-ARS-30-45D (ready: 4pcs(1 for PR2, 1 for SR2, 2 spares))

Fiber optics

Drawings

Conceptual

Noisebudget

Documents

KAGRA/Subgroups/IOO/ALS (last edited 2022-05-09 20:33:42 by miyoki)