ELECTROMAGNETIC ANGULAR ROTATION SENSING.

Studies were conducted on adapting the Sperry travelingwave ring laser for rotation sensing. Various optical combiners were evaluated to minimize coupling between the oppositely directed waves while maximizing SN ratios and permitting the sense of rotation to be determined without recourse to biasing. Coupling effects due to dust particles and mirror surface imperfections were also considered in relation to their effects on mode locking. A region of nonlinear oscillation just prior to frequency pulling and locking, at low rotation rates, was clearly established and related to the mode coupling problem. Various biasing schemes were employed to circumbent mode locking. A theoretical analysis of mode coupling effects in a linear cold cavity was accomplished using the analogy of a closedloop twin-line with a lumped shunt susceptance. In addition, a general theoretical treatment of optical resonators resulted in a graphical technique, which considerably simplifies the design and analysis of any specific ring laser system. Author