Optical Fiber Ring Resonator Research Articles

Study of the influence of temperature on the opticalscheme of a resonator fiber-optic gyroscope

The article presents a study of the temperature effect on the optical circuit of a resonator fiberoptic gyroscope (RFOG), as well as a study of the temperature effect on the half-wave voltage of the phase modulator, the effect on the spectra and power of the superluminescent diode, and the output amplitude-frequency characteristic of the fiber-optic ring resonator. The results of the study showed that in the temperature range from -30 to +50 °C has a significant effect on the parameters of the optical circuit of the RFOG. This study is an important stage in the development of the RFOG, indicating which parameters must be especially carefully monitored during further development of the sensor to ensure the temperature stability of the device.

Optical tactile sensor based on flexible optical fiber ring resonator for intelligent Braille recognition

Optical tactile sensor based on flexible optical fiber ring resonator for intelligent Braille recognition

Sensitivity improvement of the closed-loop resonant fiber-optic gyroscope interrogated with a broadband source

The resonant fiber-optic gyroscope (RFOG), interrogated with a broadband light source, represents an intriguing optical gyroscope that has been proposed as an extension of the traditional RFOG, which is driven by a narrow linewidth laser source. The implementation of a closed-loop detection system enhances the linearity and dynamic range of the gyroscope output. This paper is devoted to improving the sensitivity of the closed-loop broadband source-driven RFOG. First, a model for analysis and optimization of the feedback loop gain of a closed-loop broadband source-driven resonant fiber-optic gyroscope (RFOG) is developed, and the feedback loop gain is optimized. The experimental results indicate that the influence of the feedback loop noise on the gyro performance can be neglected. Subsequently, the noise contributions, including the shot noise, detector noise, and relative intensity noise, in the broadband source-driven RFOG system are investigated. A theoretical derivation and experimental verification of an expression for the reduction of the relative intensity noise by a fiber-optic ring resonator are presented. Finally, a packaged broadband source-driven RFOG prototype using a 175 m long fiber coil with an average diameter of 5.7 cm was constructed and evaluated. The experimental results demonstrate that the prototype achieves navigation-grade precision with an angular random walk of 0.003∘/h1/2 and a bias instability of 0.005°/h.

Resonant fiber optic gyroscope driven by a broadband light source based on an over-coupled state fiber ring resonator

The resonant fiber optic gyroscope (RFOG) driven by a broadband light source has advantages over conventional RFOGs in terms of structure, solution, etc., and provides new ideas for the commercialization of RFOGs. In this paper, the basic working principle of RFOG driven by a broadband light source is introduced. The optimal modulation coefficients are provided for sinusoidal wave modulation. The influence of the length of the fiber-optic ring resonator (FRR) and the coupling coefficient of the fiber coupler on the sensitivity is analyzed. The FRR is constructed in the over-coupled state to improve the utilization of optical power, and thus significantly increase the system sensitivity. In experiments, an RFOG prototype with a diameter of 13 cm, a height of 7 cm, and a fiber ring length of 210 m is produced. A bias instability (BI) of 0.06°/h and an angular random walk (ARW) of 0.01∘/h are obtained.

Design of a high sensitivity and wide range angular rate sensor based on exceptional surface

Abstract It is found that when the parity–time symmetry phenomenon is introduced into the resonant optical gyro system and it works near the exceptional point, the sensitivity can in theory be significantly amplified at low angular rate. However, in fact, the exceptional point is easily disturbed by external environmental variables, which means that it depends on harsh experimental environment and strong control ability, so it is difficult to move towards practical application. Here, we propose a new angular rate sensor structure based on exceptional surface, which has the advantages of high sensitivity and high robustness. The system consists of two fiber-optic ring resonators and two optical loop mirrors, and one of the resonators contains a variable ratio coupler and a variable optical attenuator. We theoretically analyze the system response, and the effects of phase and coupling ratio on the system response. Finally, compared with the conventional resonant gyro, the sensitivity of this exceptional surface angular rate sensor can be improved by about 300 times at low speed. In addition, by changing the loss coefficient in the ring resonator, we can achieve a wide range of 600 rad/s. This scheme provides a new approach for the development of ultra-high sensitivity and wide range angular rate sensors in the future.

Research on Optical Fiber Ring Resonator Q Value and Coupling Efficiency Optimization.

The coupling efficiency of the fiber ring resonator has an important influence on the scale factor of the resonant fiber gyroscope. In order to improve the scale factor of the gyroscope, the coupling efficiency of the fiber ring resonator and its influential factors on the scale factor of the gyroscope are analyzed and tested. The results show that the coupling efficiency is affected by both the splitting ratio of the coupler and the loss in the cavity. When the coupling efficiency approaches 0.75 at the under-coupling state, the scaling factor of the gyroscope is the highest. This provides a theoretical reference and an experimental basis for the enhancement of the scaling factor of the resonant fiber gyroscope with the fiber ring resonator as the sensitive unit, providing options for multiple applications such as sea, land, sky and space.

Performance improvement of white-light-driven resonant fiber optic gyroscope using four-frequency sawtooth wave modulation technology

In this study, a novel resonant fiber optic gyroscope (RFOG) that relies on four-frequency sawtooth wave modulation technology is proposed. This innovative approach is utilized to demodulate both the light intensity changes of the optical system and the half-wave voltage drift of the multi-functional integrated optical chip (MIOC). The principle of modulation is expounded, and a simulation model is established to evaluate the performance of the system. We conducted synchronous compensation of the bias drift, which is caused by the light intensity changes, and applied closed-loop control to MIOC modulation frequency-shift voltage, effectively reducing the scale factor error. As a result, the system achieved a bias instability (BI) of 0.0055°/h, with a 500 m-long fiber-optic ring resonator (FRR) of 6 cm diameter, at room temperature. Furthermore, the scale factor error was reduced by more than threefold in the temperature range of −40 °C to 70 °C. These results demonstrate the superior performance of the proposed RFOG and its potential for high-precision navigation and other applications.

Navigation-grade three-axis resonant fiber-optic gyroscope employing a multiplexed source.

A three-axis gyroscope is a vital component of an inertial measurement unit that can measure the rotation rates in three directions simultaneously. A novel three-axis resonant fiber-optic gyroscope (RFOG) configuration with a multiplexed broadband light source is proposed and demonstrated. The output light from the two vacant ports of the main gyroscope is reused as drive sources for the other two axial gyroscopes, which effectively improve the power utilization of the source. The interference between different axial gyroscopes is effectively avoided by optimizing the lengths of three fiber-optic ring resonators (FRRs) rather than by inserting other optical elements in the multiplexed link. With the optimal lengths, the influence of the input spectrum on the multiplexed RFOG is suppressed and a theoretical temperature dependence of the bias error as low as 1.08 × 10-4 °/h/°C is obtained. Finally, a navigation-grade three-axis RFOG is demonstrated with a fiber coil length of ∼100 m for each FRR.

Reduction of relative intensity noise in a broadband source-driven RFOG using a high-frequency modulation technique.

A broadband source-driven resonant fiber-optic gyroscope (RFOG) can reduce coherence-related noise, thus achieving a better sensitivity with a much simpler configuration than the traditional system with a coherent source. Its detection sensitivity, however, is still limited by the excess relative intensity noise (RIN) of the broadband source. In this paper, the RIN error mechanism in this broadband source-driven RFOG is revealed and countermeasures are presented. We demonstrate that the use of a high-finesse fiber-optic ring resonator and a high-frequency modulation-demodulation technique can reduce the RIN-induced error. It is indicated that the optimal modulation parameters can provide a RIN-induced error reduction of 6.1 dB, allowing the broadband source-driven RFOG to operate near the shot-noise-limited theoretical sensitivity. With the optimal high-frequency modulation-demodulation technique, an angle random walk of 0.0013°/√h is achieved with a 200-m-long fiber-optic ring resonator of 7.6 cm diameter. This is the best result reported to date, to the best of our knowledge, for fiber-optic gyroscopes of this size.

Performance of a resonant fiber-optic gyroscope based on a broadband source.

A resonant fiber-optic gyroscope (RFOG) based on a broadband source can avoid the fundamental drawback of coherence detection processing while possessing the greater sensitivity afforded by the finesse of the fiber-optic ring resonator. In this paper, the basic operation principle is presented and demonstrated in detail, and various noise sources, as well as the temperature effect encountered in this broadband source-driven RFOG, are studied and analyzed. Then a combined modulation technique is proposed to suppress the residual backscattering noise. To further reduce the effect of temperature transience, an asymmetric fiber ring resonator is designed. In the experiment, a bias stability of 0.01°/h is successfully demonstrated with a 100 m-long fiber ring resonator of 8 cm diameter in a laboratory environment without temperature control.

Studies on passively Q-switched ytterbium doped all-fiber laser using fiber optic ring resonator

We report our studies on ytterbium doped fiber laser passively Q-switched by fiber optic ring resonator in all-fiber format. The Q-switched laser characteristics viz. pulse duration, pulse profile, repetition rate and average power are easily varied not only by pump power but also by changing the polarization state of light inside the laser resonator with the help of polarization controllers. At 330 mW pump power, the laser generates 1.07 μs duration pulses with 0.68 μJ pulse energy at 83.6 kHz repetition rate. The Q-switched laser wavelength is tunable from 1059 to 1069.7 nm by changing the polarization state inside the cavity.

Breathing dynamics of symmetry-broken temporal cavity solitons in Kerr ring resonators.

We investigate theoretically and experimentally the instabilities of symmetry-broken, vectorial, bright cavity solitons (CSs) of two-mode nonlinear passive Kerr resonators. Through comprehensive theoretical analyses of coupled Lugiato-Lefever equations, we identify two different breathing regimes where the two components of the vectorial CSs breathe respectively in-phase and out-of-phase. Moreover, we find that deep out-of-phase breathing can lead to intermittent self-switching of the two components, spontaneously transforming a soliton into its mirror-symmetric state. In this process, solitons are also sometimes observed to decay. All our theoretical predictions are confirmed in experiments performed in an optical fiber ring resonator, where CS symmetry breaking occurs across the polarization modes of the resonator. To the best of our knowledge, our study constitutes the first experimental report of breathing instabilities of multi-component optical solitons of driven nonlinear resonators.

White-light-driven resonant fiber-optic gyro based on round trip filtering scheme.

As the second generation of the fiber-optic gyro (FOG), a resonant FOG (RFOG) appears as a very viable candidate for a miniaturized optical gyro. However, due to the impediment of laser-induced parasitic noise and system complexity, the actual performance of the RFOG is well below expectations. This paper proposes a novel, to the best of our knowledge, RFOG which is driven by broadband white light rather than a narrow linewidth laser. The fiber-optic ring resonator (FRR) works as a filter, and the rotation under detection is read out from the round trip loss of the FRR. The parasitic noise is effectively avoided due to the low coherence light, and the measuring resolution can be thus improved. In the experiment, a bias instability of 0.012 ∘/h is demonstrated with a 100-m fiber coil and a very simple structure. The proposed method would be a big step forward for making the RFOG practical with high performance and low cost.

Wavelength and throughput tuning of FORR-based optical filter using Sagnac effect

Abstract In this paper, analysis of tunable optical filter based on Sagnac effect tuning is presented using a fiber-optic ring resonator (FORR) and the responses of the filters for different FORR and Sagnac loop parameters under steady-state conditions are investigated. Formulation of the optical filter response is presented by considering with/without single and multiple Sagnac loop effects. Effects of the FORR parameters of filter response are studied and analyzed under different parametric conditions for the maximum transmission intensity. The simulation results show that the filter responses are affected strongly by the Sagnac loop and the FORR parameters. With the Sagnac effect, it is shown that full-width at half maximum (FWHM) would increase by increasing the phase difference Δϕ from 0 to 0.20 radian, beyond which it will start decreasing. The difference in FWHM value in this range of Δϕ variations is found to be about 3.77 nm. Between the first and the second resonances at wavelengths 1395 and 1538 nm, the free spectral range (FSR) is found to be 140 nm. In multiple loops effects, by increasing the number of loop turn N, the values of FSR would reduce. For Δϕ = 0.3 and N = 1, 2, 3, the values of FSR are obtained as 144, 74, 47 nm, respectively.

Tunable Fano and EIT-Like Resonances in a Nested Feedback Ring Resonator

In this paper, we realize tunable Fano and electromagnetically induced transparency (EIT)-like resonances in the outputs of a nested feedback ring resonator. Compared with the traditional add-drop ring resonator, the feedback arm introduces interference between different resonance modes. Using coupled mode theory, we reveal that the output Fano resonances are the interference of discrete modes and continuum modes, whereas the EIT-like resonance only appears in the over-coupled state. We experimentally confirm the two effects using optical fiber ring resonators, finding that the Fano effect can be easily controlled with phase shifts in the feedback arm. Moreover, we achieve the double Fano resonance, which displays an ‘X’ type lineshape utilizing one ring resonator, predicting it to be a good candidate in wavelength monitor. The proposed simple configuration provides a platform to study Fano and EIT-like effect, which is useful in the optical filter, fast and slow light, optical switching, and optical sensing.

Dissipative Polarization Domain Walls in a Passive Coherently Driven Kerr Resonator.

Using a passive, coherently driven nonlinear optical fiber ring resonator, we report the experimental realization of dissipative polarization domain walls. The domain walls arise through a symmetry breaking bifurcation and consist of temporally localized structures where the amplitudes of the two polarization modes of the resonator interchange, segregating domains of orthogonal polarization states. We show that dissipative polarization domain walls can persist in the resonator without changing shape. We also demonstrate on-demand excitation, as well as pinning of domain walls at specific positions for arbitrary long times. Our results could prove useful for the analog simulation of ubiquitous domain-wall related phenomena, and pave the way to an all-optical buffer adapted to the transmission of topological bits.

Experimental observations of bright dissipative cavity solitons and their collapsed snaking in a Kerr resonator with normal dispersion driving

Driven Kerr nonlinear optical resonators can sustain localized structures known as dissipative Kerr cavity solitons, which have recently attracted significant attention as the temporal counterparts of microresonator optical frequency combs. While conventional wisdom asserts that bright cavity solitons can only exist when driving in the region of anomalous dispersion, recent theoretical studies have predicted that higher-order dispersion can fundamentally alter the situation, enabling bright localized structures even under conditions of normal dispersion driving. Here we demonstrate a flexible optical fiber ring resonator platform that offers unprecedented control over dispersion conditions, and we report on the first experimental observations of bright localized structures that are fundamentally enabled by higher-order dispersion. In broad agreement with past theoretical predictions, we find that several distinct bright structures can coexist for the same parameters, and we observe experimental evidence of their collapsed snaking bifurcation structure. Our results also elucidate the physical mechanisms that underpin the bright structures, highlighting the key role of spectral recoil due to dispersive wave emission. In addition to enabling direct experimental verifications of a number of theoretical predictions, we show that the ability to judiciously control the dispersion conditions offers a novel route for ultrashort pulse generation: the bright structures circulating in our resonator correspond to pulses of light as short as 230 fs—the record for a passive all-fiber ring resonator. We envisage that our work will stimulate further fundamental studies on the impact of higher-order dispersion on Kerr cavity dynamics, as well as guide the development of novel ultrashort pulse sources and dispersion-engineered microresonator frequency combs.

Stabilizing DFB laser injection-locked to an external fiber-optic ring resonator

Self-injection locking to an external fiber cavity is an efficient technique enabling drastic linewidth narrowing and self-stabilization of semiconductor lasers. The main drawback of this technique is its high sensitivity to fluctuations of the configuration parameters and surroundings. In the proposed laser configuration, to the best our knowledge, for the first time the self-injection locking mechanism is used in conjunction with a simple active optoelectronic feedback, ensuring stable mode-hopping free laser operation in a single longitudinal mode. Locking to 4-m length fiber resonator causes a drastic narrowing of the DFB laser linewidth down to 2.8 kHz and a reduction of the laser phase noise by three orders of magnitude. We have explored key features of the laser dynamics with and without active feedback, revealing stability and tunability of the laser linewidth as an additional benefit of the proposed technique.

Comparison of Self-Injection Locking of DFB-LD by Optical Fiber and Optical Waveguide Ring Resonators

ABSTRACTUtilizing the frequency selection characteristic of ring resonators, self-injection-locking linewidth narrowing and frequency stabilization of distributed feedback laser diodes (DFB-LDs) can be achieved under the aid of ring resonators. In this paper, the self-injection-locking effects of a DFB-LD realized by two fiber ring resonators and an optical waveguide ring resonator are compared. The influences of the resonant peak bandwidth and transmission on linewidth narrowing are demonstrated. It is shown that the mode hopping can be significantly suppressed by employing the optical waveguide ring resonator. This is of great significance for practical applications and integration of the self-injection-locked DFB-LDs.

Temperature effect on optical filter based on fiber-optic resonator using polarization and birefringence effects in the resonator loop

In this paper an analysis of optical filter based on fiber-optic ring resonator using polarization and birefringence effects in the resonator loop is presented. The temperature variations, which affect the refractive index and radius of the ring, would cause a change in the filter response. The simulation results show that the resonant wavelengths would shift toward longer wavelengths and output intensity changes with increasing temperature. It is shown that for every 10 deg C change in temperature, would cause the resonance wavelength to increase by 0.1 .