Novel optical vibration sensor using external cavity feedback

Christine Mignosi, Roger P. Griffiths, Michal Bordovsky, Christopher N. Morgan, Ian H. White, Nicholas A J Lieven

Research output: Contribution to journalConference articlepeer-review

1 Citation (SciVal)


A novel low cost, non-contact optical vibration sensor requiring only a single optoelectronic component has been developed. It consists of a CW semiconductor laser operating with external optical feedback. The laser beam reflected from a target generates a series of lasing modes set by the external cavity length. Beating of the modes produces an RF signal and this signal is detected as a variation in the junction voltage. Any change in the external cavity length induces corresponding beat frequency variations in the RF signal, which are transformed into amplitude variations using a simple edge-detection filter system. Using this sensor, low amplitude vibrations have been measured at frequencies of up to 600 Hz. Successful results have been achieved with target reflectivities lower than 5%. When calibrated, the sensor demonstrates satisfactory output for submicron vibration amplitudes. Maximum amplitudes of 1 mm have been measured with an accuracy of 0.2%.

Original languageEnglish
Pages (from-to)14-22
Number of pages9
JournalProceedings of SPIE - The International Society for Optical Engineering
Publication statusPublished - 1 Jan 1999
EventProceedings of the 1999 Testing, Packaging, Reliability, and Applications of Semiconductor Lasers IV - San Jose, CA, USA
Duration: 28 Jan 199928 Jan 1999

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics


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