SOURCED LOCKED FREQUENCY MODULATED DUAL SERVO PRLG

Abstract

A passive ring resonator gyroscope comprising a single piece body having an integral first and second resonator cavity. The first resonator cavity contains a single frequency laser that provides a sharply tuned single frequency light source to the second resonator cavity. The single frequency light source is split to form first and second sources. The second resonator cavity is a passive high Q cavity with a closed second optical path. The two light sources are fed into the second resonator and propagate as CW and CCW beams within the second resonator. A first servo channel develops a first control signal to tune the frequency of the CW beam to a resonance peak. A second servo channel develops a second control signal to tune the CCW beam to its resonance peak. By converting both servo error outputs into frequency, the relative frequency difference between the CW and CCW beams are recorded as the frequency shift in response to the body rate rotation about the sensitive axis. The first and second control signals are algebraically added to provide a linear laser difference servo signal which is integrated, to provide a passive cavity servo signal or, in an alternative embodiment, a laser cavity servo signal. The passive cavity servo signal is used to drive a passive cavity PZT to tune the passive cavity to be resonant at a center frequency midrange between the first and second offset frequencies. In the alternative embodiment, the cavity servo signal is used to adjust the linear laser path length to keep the linear laser center frequency at a frequency midrange between the first and second offset frequencies.

Source: Google Patents

35 USC §181 Secrecy Order

Inventor

• 1KIE L. SOOHOO

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