Ring Laser Gyroscope Operating at Exceptional Point with Extremely High Sensitivity

Following Phase-I’s achievement of objectives, Phase-II will focus on fabrication and characterization of an innovative gyro that will demonstrate experimentally for the first time the feasibility of capitalizing on exceptional points to produce chip-scale gyros with unprecedented sensitivity. This design incorporates three novel key elements. Unlike most exceptional-point systems, instead of two coupled rings it utilizes a single ring resonator, in which the two modes counter-propagate and are coupled together by a grating. Because they share the same resonator, this structure is reciprocal and far more thermally stable than two-ring configurations. To overcome the strong excess (Petermann) noise that normally dominates in exceptional-point lasers, differential gain saturation is enforced by ensuring that the TE00 mode lases in one direction, and the TE01 mode in the other. Finally, this structure will be fabricated in InP, a gain medium that brings in the convenience of electrical pumping, well-established monolithic integration, and the narrow homogenous linewidth required to lase at two frequencies and measure extremely small rotation-induced splitting. With a ring diameter of only 1 cm, this gyro is predicted to achieve an ARW as low as 0.001 deg/?h, while exhibiting a good thermal stability and benefiting from easy of large-scale, low-cost fabrication.