Accession Number : ADD012198

Title :   Interferometric Hydrophone Reference Leg Low Frequency Compensation.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Assard,Gerald L

Report Date : 11 Feb 1986

Pagination or Media Count : 4

Abstract : An interferometer inhibits a received low frequency acoustic signal that is below the pass band of interest from appearing in the output. The interferometer has a conventional optical hydrophone in the signal leg to sense both the high and low frequencies of an acoustic signal. The reference leg has means of accepting a low frequency acoustic signal to modulate the coherent light path length while inhibiting the desired high frequency signal. On recombining the signals from both the signal and reference legs the low frequency signal appearing in both legs is canceled and only the high frequency signal appearing in the signal leg reaches the output. In an alternate embodiment the reference leg mandrel is placed internal to the sensor mandrel and provides a low frequency compensation chamber.

Descriptors :   *PATENTS, *HYDROPHONES, *INTERFEROMETERS, UNDERWATER SOUND EQUIPMENT, OPTICAL EQUIPMENT, FIBER OPTICS TRANSMISSION LINES, MANDRELS, HOUSINGS, FREQUENCY RESPONSE, COMPENSATION, LOW FREQUENCY, CHAMBERS, ACOUSTOOPTICS

Subject Categories : Acoustic Detection and Detectors
      Fiber Optics and Integrated Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE