title: Expansion of linear range of Pound-Drever-Hall signal.
abstract: We propose new solutions for expanding the linear signal range between the laser frequency deviation (or mirror position) and the voltage signal derived by the Pound-Drever-Hall (PDH) method for optical Fabry-Perot cavity resonance control. One solution is to perform not in-phase demodulation but near-Q-phase demodulation. Another solution is to take a suitable combination of signals demodulated by odd-harmonic modulation frequencies in the in phase. Although the PDH signal sensitivity will be diminished, the PDH signal linear range can be extended. From a practical standpoint, it is desirable that a sideband frequency for the PDH method is near the FP cavity resonance.
authors.affiliation: Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8582 Japan. miyoki@icrr.u-tokyo.ac.jp
authors.forename: Shinji
authors.initials: S
authors.lastname: Miyoki
authors.forename: Souich
authors.initials: S
authors.lastname: Telada
authors.forename: Takashi
authors.initials: T
authors.lastname: Uchiyama