{
  "$type": "site.standard.document",
  "description": "In a fiber optic rotation sensor, a portion of the coiled optical fiber is a part of and affected by a bias optical phase modulator which causes a varying phase relationship between the light waves at a fundamental frequency. However, the varying phase relationship has at least one harmonic which…",
  "path": "/patents/1111794",
  "publishedAt": "2001-07-11T00:00:00.000Z",
  "site": "at://did:plc:oql6ds5vnff4ugar6rruliwd/site.standard.publication/3mn3ohu7oxx5w",
  "tags": [
    "G01C19/72",
    "HONEYWELL INC [US]"
  ],
  "textContent": "In a fiber optic rotation sensor, a portion of the coiled optical fiber is a part of and affected by a bias optical phase modulator which causes a varying phase relationship between the light waves at a fundamental frequency. However, the varying phase relationship has at least one harmonic which is due to mechanical vibration of the optical fiber that is a part of the modulator. This harmonic contributes to an erroneous indication of rotation. The amplitude of such harmonic is reduced by lowering the Q of the resonating fiber. This is effected by applying a damping material to the optical fiber and a portion of the modulator. A photodetector detects the counter-propagating waves and sends a corresponding electrical signal on to a signal component selection device that provides an indication of sensed rotation, including error due to the mechanically resonating optical fiber of the modulator.",
  "title": "Phase modulation error reduction"
}