Ultralow-noise broadband source for interferometric fiber optic gyroscopesemploying a semiconductor optical amplifier.

A novel scheme of an ultralow relative intensity noise (RIN) broadband source module employing a double pumped backward (DPB) Er-doped superfluorescence fiber source (EDSFS) and a semiconductor optical amplifier for interferometric fiber optic gyroscopes (IFOGs) is proposed. With optimized parameters, the optimal twin-peak output profile of the source is obtained. The effective optical spectrum width of the source is 38.6 nm, and the output power is about 12.5 mW. Compared with the DPB EDSFS with a similar spectrum, the ultralow RIN broadband source proposed demonstrates a lower RIN of about 8.4 dB. A high-precision IFOG utilizing the ultralow RIN broadband source is set up, and the performance of the IFOG is experimentally studied. An angle random walk coefficient of 6.93×10-5o/h1/2 is demonstrated, which is reduced by about 31.5% compared with the same IFOG system utilizing conventional DPB EDSFS with a similar spectrum profile. The ultralow RIN broadband source module proposed is quite feasible for high-precision IFOGs used in strategic-grade navigation systems and satellites.

Transmissive resonant fiber-optic gyroscope employing Kagome hollow-core photonic crystal fiber resonator.

A novel scheme for a double closed-loop resonant fiber-optic gyroscope (R-FOG) employing a high-performance transmissive Kagome hollow-core photonic crystal fiber (HCPCF) resonator is proposed. We use specially designed Kagome HCPCFs and a meniscus lens module to form a resonator, whose finesse is 58.2 with a length of 5.6 m and a diameter of 13 cm; the theoretical sensitivity of the R-FOG is better than 0.05°/h. Based on the novel Kagome HCPCF resonator, a double closed-loop R-FOG is set up and the performance of the R-FOG system is experimentally studied. It demonstrates that white noise dominates in the output at the integration time of 200 s and a bias stability of 0.15°/h and angle random walk coefficient of $0.04^{\circ}\,{\rm h}^{1/2}$0.04∘h1/2 are achieved. Over a dynamic range of ${-}{100}^\circ {\rm /s}$-100∘/s to 100°/s, the scale factor nonlinearity of the FOG is 310 ppm, which shows significant improvement compared with the single closed-loop R-FOG system. The novel double closed-loop R-FOG proposed is quite feasible for tactical grade applications.

Radiation-resistant flatness-shaped spectrum erbium-doped photonic crystal fiber source employing multiple self-compensating methods.

A novel scheme of radiation-resistant flatness-shaped spectrum erbium-doped photonic crystal fiber source (EDPCFS) employing multiple self-compensating methods is proposed. We first develop a sort of radiation-resistant highly erbium-doped photonic crystal fiber (EDPCF) with the cutoff wavelength of 520 nm, which ensures that the pump light and most energy of the green light from upconversion of Er3+ could participate in photo-annealing to reduce the radiation-induced background attenuation (RIBA) of the EDPCFS under radiation environment. To minimize the spectrum variation from radiation-induced active band attenuation (RIABA), the original spectrum is optimized employing an improved double pumped backward (DPB) configuration. With a gain flattening filter and closed-loop feedback control technology, a radiation-resistant EDPCFS with a linewidth larger than 41 nm is achieved, and it experimentally demonstrates a significantly improved mean-wavelength stability of 0.42 ppm/krad with the output power attenuation of 0.09 dB underγ-irradiation of 200 krad. The novel radiation-resistant EDPCFS proposed is quite feasible for strategic interferometric fiber-optic gyroscopes (IFOGs) working in high-dose radiation environment.