Honeywell G.m.b.h.

Honeywell International Inc.

James W Bergstrom

Mark W Weber

Theodore J Podgorski

J Allen Cox

Teresa A Fritz

A diffractive optical element is interposed between the exit beams from a ring laser gyro readout and the photodetectors for detecting such beams. The diffractive optical element permits the use of photodetectors much reduced in size in order to minimize gyro performance degradation due to radiation.

Radiation-hardened RLG readout

In the present invention, a prismatic structure receives the small portions of the counter-propagating waves which are transmitted through a partially transmitting mirror at one of the corners of the gyro. Exiting from the prismatic structure is a light beam which is redirected by a concave mirror which serves to cause the light beam to travel along a first light path and also cause the impinging light beams to be focused at a selected point at which the beam size thereat is less than the original beam size impinging upon the concave mirror. Further, the concave mirror is positioned such that the light path reflected from the concave mirror passes through the prismatic structure so as to minimize the readout assembly bulk optic size, thus being more compact.

A pair of photodetector output signals are positioned so as to be responsive to the interference pattern produced by the pair of laser beams of the ring laser. The photodetectors are positioned such that the output signals are in phase quadrature. A second pair of signals is derived from the first pair of signals in which the second pair are displaced in phase relative to the first pair and are also in phase quadrature. The two pairs of signals are signal processed to enhance resolution of the ring laser readout.

Readout for a ring laser angular rate sensor

A symmetrical prismatic readout apparatus includes a pair of substantially identical prism elements positioned in back-to-back relationship with respect to each other to provide a symmetrical structure. The prism elements have bonding surfaces in which one includes a thin film platinum coating. The bonding surfaces are bonded together through optical bonding, without the use of adhesives. The platinum film forms a beam splitter. The two prism elements are similarly bonded to a substrate element, again by optical bonding, without the use of adhesives. Suitable beam splitter arrangements are provided to effect the desired readouts.

Readout for a ring laser gyro using a platinum beam splitter

A symmetrical prismatic readout apparatus includes a pair of substantially identical prism elements positioned in back-to-back relationship with respect to each other to provide a symmetrical structure. The prism elements are bonded together through optical bonding, without the use of adhesives. The two prism elements are similarly bonded to a substrate element, again by optical bonding, without the use of adhesives. Suitable beam splitter arrangements are provided to effect the desired readouts.

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New Brighton, MN, United States of America

James W Bergstrom