Research On Diode-pumped Single-frequency Bidirectional CW Solid-state Ring Laser

The next generation optical gyro will trend to high accuracy, all-solid-state and small size. As a novel concept optical gyro which has many advantages, solid-state ring laser gyro (SSRLG) must be one of promising alternatives. Continuous wave (CW) solid-state ring laser is the key part of SSRLG. To author's knowledge, there is no CW solid-state ring laser used in optical gyro reported before in the world. Supported by Project "research on miniaturization of SSRLG", this dissertation is involved in theoretical and experimental research on diode-pumped single-frequency bidirectional CW solid-state ring laser, attaining single-frequency, bidirectional, CW solid-state ring laser. The configuration of the ring laser is analyzed and the characteristic of bidirectional ring laser is studied in detail in this dissertation.Diode-Pumped 4-mirror 8-type cavity bidirectional solid-state ring laser is proposed, in which Nd:YVO4 is selected as laser media. Author investigates the laser's operation principle and its potential accuracy. By exploiting ABCD transmission matrix theory, the influence on cavities' stability and eigenmode by the ROC and separation distance of curved mirrors and cavities' length is analyzed. The eigenmode and the stability condition of ring cavity is theoretically calculated deeply. Taken into the thermal lens effect of laser crystal, the cavities' thermal stability also is researched, which indicates that stability and the configuration of the ring laser is perfect. The characteristic of the bidirectional output of the laser which is pumped by LD lens-coupled pump and LD fiber-coupled pump respectively is experimentally studied in this dissertation. The experimental result shows that the laser is operated in multimode state without mode selector in the cavity in which a homogenous-broaden gain laser media is exploited. By inserting a diagram in the ring cavity, multi-longitudinal mode and TEM00 mode outputs are realized. The laser output is linearly polarized in the direction perpendicular to the ring cavities' plane. Single-longitudinal mode and TEM00 mode continuous wave outputs are obtained with an F-P etalon inserted in the ring cavity. Diode-pumped single-frequency bidirectional CW solid-state ring laser has been operated and its output powers are measured, the stability of which is 0.4% in 100s sampling time. The linewidth of the single-frequency was about 4 kHz in 1.5s sampling time when the output power is 0.2mW. Experimental results do prove that Diode-pumped solid-state ring laser which exploited a homogenous-broaden crystal as laser media can be operated in single-frequency, bidirectional output, stable state. And any traveling wave does not extinguish or be unstable for mode competition. Additionally the folded resonator laser composed by the inserted F-P etalon was experimentally studied.In the end of the dissertation, the rotation experiment of ring laser was experimentally investigated and the results show that the interfering fringe is stationary or randomly dithered when the stage is rotating, which indicates the bidirectional beam in the ring laser is lock-in. That the intension distribution and contrast of interfering fringe was stationary indicates that the bidirectional, single-frequency CW ring laser can be operated stably when the ring resonator is rotating.