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Vibration characteristic analysis. (a) Resonant frequencies measurement. The degradation (increment) of the IPN under particular vibration amplitude at particular frequency is represented by the color of each point in the image. (b) Phase spectral density of the fr under the vibration of acoustic impulse. The offset frequency is shown as the vertical axis and in linear scale.
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We demonstrate an all polarization-maintaining (PM) fiber-based optical frequency comb and provide the detailed environmental stability analysis results. The frequency comb has been built by commercial available PM fiber completely, and its static uncertainty in optical domain is 350 Hz in 1 s when referenced to a low noise oven controlled crystal...
Citations
... Additionally, the optical component of the fiber comb system was placed on a vibrating platform with an integrated acceleration of 0.5 g; the fceo and fbeat were also able to maintain phase locking [75]. In 2015, Feng et al. developed an all-polarization-maintaining Er:fiber comb using the SESAM mode-locking principle and analyzed in detail the effects of different environ mental factors, including acoustic resonant frequencies, laser-operating temperature, and humidity, on the fiber comb system [76]. ...
... Additionally, the optical component of the fiber comb system was placed on a vibrating platform with an integrated acceleration of 0.5 g; the f ceo and f beat were also able to maintain phase locking [75]. In 2015, Feng et al. developed an all-polarization-maintaining Er:fiber comb using the SESAM mode-locking principle and analyzed in detail the effects of different environmental factors, including acoustic resonant frequencies, laser-operating temperature, and humidity, on the fiber comb system [76]. ...
Optical frequency combs have emerged as a new generation of metrological tools, driving advancements in various fields such as free-space two-way time–frequency transfer, low-noise microwave source generation, and gas molecule detection. Among them, fiber combs based on erbium-doped fiber mode-locked lasers have garnered significant attention due to their numerous advantages, including low noise, high system integration, and cost-effectiveness. In this review, we discuss recent developments in erbium-doped fiber combs and analyze the advantages and disadvantages of constructing fiber combs utilizing different erbium-doped mode-locked fiber lasers. First, we provide a brief introduction to the basic principles of optical frequency combs. Then, we explore erbium-doped fiber combs implemented utilizing various mode-locking techniques, such as nonlinear polarization rotation (NPR), real saturable absorber (SA), and nonlinear amplifying loop mirror (NALM). Finally, we present an outlook on the future perspectives of erbium-doped fiber combs.
... To improve the characteristics of picosecond or femtosecond vector solitons, fiber-based mode-locked pulse lasers have been widely investigated in recent years [1][2][3][4][5][6]. Vector solitons are used in ultrafast processes, supercontinuum generation, distance measurement with high accuracy, and many other fields [7][8][9][10]. The most important part of fiber-based mode-locked lasers is a saturable absorber (SA) or mode-locked device. ...
We have experimentally observed an ultrashort conventional vector soliton in an erbium-doped fiber laser. The few-layered graphene oxide (GO) is used as a saturable absorber (SA). It is found that the saturable absorption characteristic of GO is polarization independent. Therefore, vector solitons can be obtained without polarization control by using such SA. By using a polarization beam splitter to split the mode-locked pulse obtained in the oscillator, two orthogonal polarization vector solitons with equal intensity and consistent characteristics can be obtained. It demonstrates that the initial soliton consists of two orthogonal polarization components. It is worth noting that these two orthogonal polarization component solitons improve the signal-to-noise ratio (SNR) of 3 dB compared with the initial soliton. The improvement in SNR is very significant and cannot be neglected. This phenomenon has not been reported before, to our knowledge. In addition, the conventional soliton generated by this mode-locked laser has a central wavelength of 1559 nm with 1.1 ps pulse duration. The mode-locking state of this laser can be self-started. After mode locking, the environmental stability is excellent. The experimental results indicate that GO as a broadband SA has great potential and application prospects in the field of vector soliton generation.
... In recent years, with the significant progress of fiber laser and amplifier, the ultrafast femtosecond laser systems with high average powers play a critical role in many applications such as high precision machining [1,2], clinical surgery [3,4], optical frequency comb (OFC) [5,6], high-harmonic generation [7,8], attosecond science [9,10], supercontinuum (SC) [11] and so on. For instance, in the process of SC generation, femtosecond pulses with a pulse duration of usually shorter than 100 fs and a peak power of 10 kW level are adopted to pump a short piece of highly-nonlinear fiber (HNLF) [11], a broadband coherent SC with low intensity noise can then be generated [12]. ...
We demonstrate a compact femtosecond fiber laser system based on all polarization-maintaining (PM) fiber and fiber components integrated structure. The figure-9 oscillator which incorporated a nonlinear amplifying loop mirror in the cavity features a 103.4-MHz high repetition rate with up to 93.1 dB signal-to-noise ratio of the radio frequency spectrum, 0.0056% [1 Hz, 1 MHz] integrated root-mean-square amplitude noise at the fundamental repetition rate and 63.7-fs timing jitter [100 Hz, 1 MHz]. Meanwhile, the fundamental repetition frequency was also locked to a stable radio frequency reference by using a self-designed frequency actuator and a relative frequency stability of 2.1 × 10⁻¹² at 1-s gate time was obtained. Moreover, benefitting from the large positive group-velocity dispersion and negative third-order dispersion at 1.5-μm wavelength band, we also achieved 48.2 fs compressed pulse duration as well as an amplified average power of 199 mW via one-stage all-PM fiber amplifier and compressor. At last, as a performance proof, by directly splicing 38-cm long PM highly nonlinear fiber to the pulse compressor, a broadband coherent supercontinuum spanning from 950 nm to 2150 nm was generated. Our all-PM fiber laser system is suitable for the further buildup of a low noise PM fiber optical frequency comb.
... Ultra-short mode-locked fiber lasers play an indispensable role in biological medicine [1], micromachining [2], and optical communication [3] because of their excellent self-starting performance, reliability, high beam quality, and flexible structure, which facilitate the development of open-air turn-key fiber frequency comb systems [4]. Polarization-maintaining (PM) fibers have already been used in fiber resonant cavities to increase the resistance to environmental perturbations, such as temperature changes, stress variations, and mechanical vibrations [5]. In addition, to accelerate the mode-locking process in the cavity, well-designed physical saturable absorbers, such as graphene [6][7][8], semiconductor saturable absorber mirrors (SESAM) [9], and carbon nanotubes [10], have been chosen to realize all-PM self-starting pulse lasers. ...
We demonstrate three typical mode-locking processes of a nonlinear amplifying loop mirror (NALM) fiber laser via a general nonlinear Schrödinger equation-based (GNLSE) simulation model. First, the pulse evolutions in the NALM cavity were separately simulated under asymmetric and weakly asymmetric conditions. We found that the splitting ratio and positions of the gain fiber can result in a suitable phase bias between clockwise and counter-clockwise beams, enabling the realization of a self-starting low-threshold operating condition. To assess the roles of the splitting ratio and gain in the mode-locking process, we simulated three pulse formation processes: in the soliton, stretched-pulse, and dissipative soliton mode-locking regimes. The simulation results show that the splitting ratio, gain, and dispersion directly influence the mode-locking condition and pulse characteristics, thereby providing effective quantified guidance for high-quality pulse generation. Finally, an experimental NALM oscillation operating under stretched pulse conditions was established to investigate the impact of the splitting ratio and pump power on the pulse characteristics. The experimental results prove that the splitting ratio, gain, and dispersion can be used to manipulate the mode-locking threshold, self-starting threshold, nonlinear effects, and pulse characteristics.
... Thus, there is still a requirement for research on these devices before they can be extensively applied. At present, from the perspective of cost, robustness, and complexity, the more attractive solution for fieldable combs is fiberbased OFCs built with all-polarization-maintaining (PM) fiber and off-the-shelf fiber components [14]- [16]. With the transition of fiber OFC, especially OFCs based on erbium-doped fiber laser, from laboratory research to outdoor applications, in different outdoor environments, including moving vehicles and sounding rockets, highly reliable and high-performance fiber OFCs have been reported [17]- [19]. ...
The large volume and weak environmental adaptability of fiber optical frequency combs (OFCs) have become the main obstacles for their applications in various fields. To address these issues, in this study, we present a compact, low-cost f-to-2f interferometer and fiber actuator with a large tuning range and a high control bandwidth for a 200-MHz OFC that is based on a 1.5-m all-polarization-maintaining fiber mode-locked laser. By employing customized fiber-coupled gradient index lenses, our f-to-2f interferometer is encapsulated in a miniature tube with a diameter of only 4 mm and a length of 40 mm, which substantially reduces the optical section size of the frequency comb as compared to conventional devices. The carrier envelope offset beat with a signal-to-noise ratio of 40 dB is detected in a resolution bandwidth of 360 kHz. In addition, a laboratory-made piezoelectric transducer-driven mechanical actuator for repetition rate regulation exhibited a large tuning range of 106 kHz (corresponding to an effective temperature drift of 53) and a high control bandwidth of approximately 1 kHz. This resulted in a robust repetition rate locking with an Allan deviation of 330 Hz at a gate time of 1 s and a residual integrated timing jitter of 418 fs [3 Hz to 1 MHz] when referenced to a hydrogen maser. Along with reducing the size and improving the environmental adaptability of the OFC, our design can also decrease the power consumption of the system significantly. Our findings provide a new direction to the development of OFCs for various applications.
... OFCs based on Er-doped fiber lasers are better choice because they are turnkey, robust, and support compact design. Er fiber-based OFCs based on non-linear amplifying loop mirror (NALM) [17][18][19], semiconductor saturable absorber mirror (SESAM) [20][21][22][23], and non-linear polarization rotation (NPR) [24][25][26] have been proven to be efficient alternatives. However, NPR with a single-mode (SM) fiber design is undesirable because its mode-locking state is easily disrupted by environmental perturbations. ...
... Sinclair el al. employed SESAM and NALM-based designs, using PM fibers, to demonstrate a self-referenced OFC based on mode locked Er-doped fiber laser that can operate outside the metrology lab [23]. Feng built a SESAM-based PM fiber OFC, which provided better environmental stability [22]. Kuse et al. reported a fully stabilized all-PM Er fiber-based OFC with a NALM optimized with an additional phase bias [18]. ...
This study details the implementation of a wavelength-tunable ultra-stable optical frequency comb (OFC), which is generated by a passively mode-locked all-polarization-maintaining Erbium (Er)-doped fiber laser based on a non-linear amplifying loop mirror. The center wavelength can be tuned from 950 to 1,080 nm and from 1,650 to 2,080 nm by adjusting the pump's power. Standard deviations of 100 μHz (τ = 1 s) for repetition rate and 330 μHz (τ = 1 s) for carrier-envelop offset frequency were measured in 15 h. The corresponding Allan deviations were 2.4 × 10−17 and 8.2 × 10−17 at 1 s. The repetition rate and carrier-envelop offset frequency of OFC were counted by a ∏-type counter from K+K Messtechnik.
... Reference [5] achieves a pulse tuning range of about 1.1 MHz by applying optical delay lines in the linear arm of a sigma cavity, while Ref. [10] achieves pulse tuning range of kHz by applying PZTs with nanometer accuracy. Most often, pulse tuning is used for repetition rate stabilization with an accuracy in the order of millihertz or even microhertz [11]. Thirdly, harmonic mode-locking (HML) is the mainstream technology for pulse multiplying. ...
We demonstrate here an environmentally stable and compact Er-doped fiber laser system capable of delivering sub-100-fs pulse duration with discontinuous selectable repetition rate from 10 to 70 MHz. This laser source employs a SESAM harmonic mode-locked soliton laser to facilitate tunable repetition rate. A single-mode-fiber (SMF) amplifier and a double-cladding-fiber (DCF) amplifier (both with double-pass configuration) bridged by a three-stage YVO4-based divider are used to manage the dispersion map and boost the seed pulses. With the help of ×8 replicas, the seed pulses are simultaneously amplified and compressed with 90% recombining efficiency, generating 4.60-nJ pulse energy at 10 MHz and 6.13-nJ pulse energy at 70 MHz. The main advantage of the proposed laser system is that when pulse repetition rate is switched on-demand, the pulse duration can be kept almost unchanged only by simply adjusting the pump powers of the fiber amplifiers, instead of changing any optical device (the spacing between gratings or the length of fibers).
... Due to the introduction of high-quality polarization-maintaining (PM) fibers and semiconductor saturable absorber mirrors (SESAM), PM-fiber-based frequency combs based on SESAM mode-locked lasers have been demonstrated to operate continuously for a long period of time and with low noise. 16,[29][30][31] Furthermore, the output laser with a highpolarization extinction ratio also results in a more compact frequency measurement system. Considering these factors, a visible frequency comb with a narrower bandwidth and higher single-mode power based on the all-PM EDF laser shows great potential for applications. ...
... In recent years the frequency comb evolved from a sensitive and complex laboratory breadboard setups to a compact and robust all-in-fiber system [1,2]. Frequency combs are used for demanding applications such as laser spectroscopy [3], ultra-low noise microwave signal generation [4], optical atomic clocks [5], absolute distance measurement [6] and time transfer [7]. ...
We demonstrate the stabilization of an all-in-fiber polarization maintaining semi-conductor saturable absorber mirror (SESAM) mode locked frequency comb oscillator with an intra-cavity waveguide electro-optic phase modulator (EOM) to a narrow linewidth HeNe laser over 46 hours. The high feedback bandwidth of the EOM allows a coherent optical lock with an in-loop integrated phase noise of 1.12 rad (integrated from 10 Hz to 3 MHz) from the carrier signal. No piezo fiber stretcher was required to guarantee long-term stabilization, preventing mechanical degradation of the optical fibers and enabling a long lifetime of the oscillator. As an application a hybrid stabilization scheme is presented, where a comb tooth is phase locked to a longitudinal mode of the large ring laser “G” located at the Geodatic Observatory Wettzell. The hybrid stabilization scheme describes the optical lock of the frequency comb to the G laser and the simultaneous compensation of the ring laser frequency drift by comparing the comb repetition rate against an active H-maser reference. In this context the ring laser reached a fractional Allan deviation of 5 · 10⁻¹⁶ at an integration time of 16384 s.
... The main cavity consists only of PM fiber. With the starting arm disengaged, the oscillator is therefore robust against environmental variations [21] in steady-state operation. While the use of NPE makes the starting arm sensitive to the environment, this does not affect the main cavity once the starting arm is disengaged. ...
We demonstrate a fiber oscillator that achieves 3 MW peak power, is easily started, and is environmentally stable. The Mamyshev oscillator delivers 190-nJ pulses that can be compressed externally to 35 fs duration. Accurate numerical modeling of the gain medium provides insight into the behavior and performance of the device.
