Offset locking with transmitted light

Document #:

JGW-T0900040-v1

Document type:

T

Submitted by:

Osamu Miyakawa

Updated by:

Osamu Miyakawa

Document Created:

27 Jul 2009, 19:07

Contents Revised:

27 Jul 2009, 19:07

DB Info Revised:

27 Jul 2009, 19:07

Abstract:

This document describes an application of the offset locking method for LCGT. This method assumes using a transmitted port and two photo detectors as high and low gain settings. Power budget, dynamic range and noise level on PDs are discussed here. Offset locking reduces the power inside arm cavities by factor of 50. It helps to avoid the disturbance of lock acquisition by the radiation pressure. However we conclude that not only offset locking but also reduction of input power during the lock acquisition is necessary.

Files in Document:

• offset_locking.pdf (67.1 kB)

Topics:

• Detector:Interferometer Sensing and Control:Length Sensing and Control
• Activity:KAGRA

Authors:

• Osamu Miyakawa
• Daisuke Tatsumi

Keywords:

Offset locking