Model: JALLAJ/5epo
Author: JALLAJ
Pipeline: sentence-similarity
Library: sentence-transformers
Tags: sentence-transformers, safetensors, bert, sentence-similarity, feature-extraction, dense, generated_from_trainer, dataset_size:1466, loss:MultipleNegativesRankingLoss, arxiv:1908.10084, arxiv:1705.00652, base_model:BAAI/bge-small-en-v1.5, base_model:finetune:BAAI/bge-small-en-v1.5, text-embeddings-inference, endpoints_compatible, region:us
Base models (finetune): id: BAAI/bge-small-en-v1.5
Card metadata: tags: sentence-transformers, sentence-similarity, feature-extraction, dense, generated_from_trainer, dataset_size:1466, loss:MultipleNegativesRankingLoss
base_model: BAAI/bge-small-en-v1.5
widget: source_sentence: How many more requests can the proposed method handle effectively compared to the RMLSA-OFC method before performance declines, based on the data in Figure 6?
sentences: is a great challenge to synchronize the pulse trains, and this will induce extra interpulse jitter. Perfect repetition rate multiplication can be realized by the temporal Talbot or self-imaging effect through propagating a periodic temporal signal in a dispersive medium under the first-order dispersion conditions.25 Further, repetition rate demultiplication could also be realized by introducing a suitable periodic temporal phase modulation to the original signal and carefully controlling the amount of dispersion.26 However, both of these two schemes mentioned above require extra optical systems out of the laser cavities to modify the repetition rates of the pulse sources. They increase the system complexity and make these systems loose their attractiveness for portable and robust device operation. An intralaser cavity method is by harmonic mode-locking (HML), where the pulse energy is quantized by the peak-power-limiting effect. Generally, much higher pump power is needed for passive HML lasers to boost its repetition rates to tens of GHz.27,28 Both the intracavity noise fluctuation and the chance of the pulse drop in-out increase along with the increase of the harmonic order.,9,29 This prevents boosting the laser repetition rate beyond 100 GHz. Although pulse sources at repetition rates beyond $100\ \mathrm{GHz}$ can be realized by employing active HML schemes,3 a stable radio frequency source is needed and it restricts the dimension and cost for integration applications of the active HML lasers., $$
Y=\frac{\gamma^{2}L^{2}}{\theta}X^{3}-\frac{2\delta_{1}\gamma L}{\theta}X^{2}+\frac{(\delta_{1}^{2}+\alpha^{2})}{\theta}X.
$$  
where $Y=\left|\psi_{\mathrm{in}}\right|^{2}$ is the pump power, $X=\left|\psi\right|^{2}$ is the intracavity power, ${\alpha}=({\alpha}_{0}L+\theta)/2$ is the total loss per roundtrip. The turning points of the function $Y(X)$ can be calculated by setting the first derivative $d Y/d X$ to zero as  
$$
3\gamma^{2}L^{2}X^{2}-4\delta_{1}\gamma L X+(\delta_{1}^{2}+\alpha^{2})=0.
$$  
The function $X(Y)$ given by Eq. (6) has a bistable region when Eq. (7) has two different real roots of $X.$ which requires $\delta_{1}^{2}>3\alpha^{2}$ . The two real roots corresponding to the two turning points of the bistable curve are given by  
$$
X_{1,2}=\frac{2\delta_{1}\pm\sqrt{\delta_{1}^{2}-3\alpha^{2}}}{3\gamma L}.
$$, To compare the proposed method with widely used state-of-the-art allocation methods, three approaches were considered: the RMLSA-OFC method [19], the First Fit (FF) algorithm, and the Random Wavelength Assignment (RWA) algorithm [20,21]. The method in [19] employs a heuristic algorithm for allocation using optical frequency combs (OFCs). In contrast, the FF method sequentially assigns resources by selecting the first available carrier that meets the bandwidth requirement, while the RWA method allocates wavelengths in a random manner, ensuring that each selected wavelength satisfies the transmission requirements.  
Figure 6 demonstrates that the method proposed in [19] can effectively allocate up to 110 requests with a low BBR, reaching a maximum value of 1.5. This indicates a lower performance compared to our method (see Figure 5). The ellipses in Figure 6 highlight regions with the highest BBR values, marking critical performance areas. A dashed line indicates the threshold at approximately 110 requests, beyond which the allocation method's performance declines as the number of requests increases. This visual representation emphasizes the system's limitations under higher demand. In contrast, our approach maintains effective allocation up to 170 requests, showing a clear difference of 60 clients.  
When comparing the results of our RMLSA-ILP-OFC approach to those of the FF method (see Figure 7), a marked increase in the Blocking-to-Bandwidth Ratio (BBR) is observed, with rejections exceeding 1 in several instances (marked in yellow and light blue). The BBR values, ranging from 1.5 to 3.0 (highlighted with red ellipses), indicate critical points that significantly affect Quality of Service (QoS). Additionally, the allocation method begins to fail at approximately 105 requests (red dotted line), leading to a sharp rise in BBR. These findings underscore the limitations of the FF method, which struggles to manage bandwidth efficiently under high-demand scenarios, highlighting the need for more robust solutions. Our approach demonstrates its superiority by maintaining resource allocations effectively up to 170 requests., source_sentence: What was the length of the Bi-EDF used as the gain medium in the experiment?
sentences: Figure 1 shows the experimental setup that is used in order to measure the relative phases between individual microcomb modes. A microcomb is generated in a microrod-resonator [7, 8] using an amplified extemal cavity diode laser that is coupled into a microresonator via a tapered optical fiber (launched power ${\approx}100~\mathrm{mW}$ , resonator quality factor $Q\approx1.8\times10^{8}$ , resonator mode spacing. $25.6\mathrm{GHz}$ ). The generated comb is amplified and sent through. a liquid crystal array based "waveshaper', that allows control of the amplitude and phase of the individual comb modes. In order to retrieve the relative phases of the comb modes, we first flatten the power in the comb modes. Then we use a computer controlled feedback loop in order to optimize the phases of the comb modes until we generate the shortest possible pulse (\*zero phases'), which is measured with an optical intensity autocorrelator. The original comb mode phases directly follow from the phases that had to be applied to generate the shortest pulse multiplied by (-1). Note that the measurement is not sensitive to linear increasing phases with frequency, which would just shift the pulse in time without changing the pulse shape. Thus we subtract any linear component from the measured phases. We also subtract the dispersion of the setup itself, which is measured by sending a reference pulse through the setup and determining the phase mask that is required to compensate for the setup dispersion. Since the microcomb enters the experimental setup in the middle of a tapered optical fiber, the setup dispersion is measured by sending the reference pulse into the setup before and after the tapered fiber and taking the average value., Fig. 1 explains the schematic diagram of the experimental setup. As a very short gain medium, we employed a Bi-EDF with a length of $1.5\mathsf{m}$ . The Bi-EDF was provided by Asahi-Glass Co., LTD [11]- [14], [18]-[22]. The fiber length was optimally determined so as to maximize the wavelength tuning range. The refractive indexes of the core and the cladding at 1550 nm were 2.03 and 2.02, respectively. The core and cladding diameters were 5.1 $\mu\mathsf{m}$ and $124\mu\mathsf{m}$ , respectively. The erbium concentration was 3250 ppm. The peak absorption levels around $980~\mathsf{n m}$ $1480\mathsf{n m}$ , and $1530\mathsf{n m}$ were 90 dB/m, 130 dB/m, and $210~\mathsf{d B/m}$ , respectively. The group-velocity dispersion (GVD) at 1550 nm was - 130 ps/nm/km. In order to achieve better mode field diameter matching, both ends of the Bi-EDF were first fusion spliced to high numerical aperture (NA) $\mathsf{S i O}_{2}$ fibers (HI980, Corning) before being spliced to conventional $\mathsf{S i O}_{2}$ fibers (SMF28, Corning). Thus, the fiber-tofiber loss at 1310 nm was 2.3 dB [11], [13]. The Bi-EDF was bidirectionally pumped with two high power laser diodes (LDs). A 974-nm LD with an output power of + 26 dBm and a 976-nm LD with an output power of + 27 dBm were used for the forward pumping and the backward pumping, respectively. These pump lights were coupled in the fiber cavity through wavelength-division multiplexed (wDM) fiber couplers. Two optical isolators ensured the unidirectional ring laser oscillation.  
Sinewave signal from a low noise microwave oscillator was amplified by a RF amplifier and then led to a $\mathsf{L i N b O}_{3}$ Mach-Zehnder intensity modulator 1 (LNMOD 1). The LNMOD 1 had an electrical bandwidth of $13.2G H z$ , an insertion loss of 3.7 dB, and an extinction ratio of 30.3 dB. The LNMOD 1 driven by the RF synthesizer achieved active mode Iocking at 10 GHz. A polarization controller 1 (PC 1) was used to align the polarization state to that of the LNMOD 1. Instead of adjusting the cavity length by a variable optical delay, the modulation frequency was adjusted in the range form 10.000563 GHz to 10.002038 GHz so that optimal mode locking was maintained., To evaluate the performance of our OPLL system using COTS ICs, residual phase noise of the OPLL was measured from $10~\mathrm{Hz}$ to $1\mathrm{GHz}$ using the setup shown in Fig. 5. The locked beat note at $2.9\:\mathrm{GHz}$ produced between SG-DBR and comb was connected to the ESA and the single-sideband (SSB) phase-noise spectral density (PNSD) was then measured. The signal power level of this measurement was $42~\mathrm{dBm}$ Figure 11 shows the residual OPLL phase noise at offsets from $10~\mathrm{Hz}$ to $1~\mathrm{GHz}$ . For the comparison, PNSD of the background, RF synthesizer at $2.9~\mathrm{GHz}$ , and comb source (through the RF beat note generated between comb lines) are superimposed in Fig. 11. The output signal power levels were kept the same during the measurement in order to obtain consistency.  
The phase noise variance from $1~\mathrm{\kHz}$ to $10~\mathrm{{\GHz}}$ is calculated to be $0.08\mathrm{\Delta}\mathrm{\}\mathrm{rad}^{2}$ corresponding to $14^{\circ}$ standard deviation from the locking point. This result is better than the one reported in [39]. As can be seen in Fig. 11, low frequency noise with a value less than 80 $\mathrm{{dBc/Hz}}$ at an offset above $200~\mathrm{Hz}$ for PNSD was achieved., whereas the same value at an offset above $10\mathrm{kHz}$ was achieved in [29, 42]. Lu et al. also reported better than $80~\mathrm{dBc/Hz}$ at offsets above $5\mathrm{kHz}$ which is again worse than the performance reported here [35]. However, the phase variance of our results is comparable with [29, 42] which could be attributed to the pedestal after $1\mathrm{kHz}$ which may be caused by a fiber path length mismatch between the comb and OPLL laser paths (see Fig. 5). Thus, after $1\ \mathrm{kHz}$ some additional noise from the slave laser is observed and contributes to the overall phase variance. Matched path length will be used in the future work., source_sentence: Which fields are accounted for in the system of nonlinearly coupled Lugiato-Lefever equations when considering two driving fields?
sentences: The system under study is schematically presented in Fig. 1. A Kerr-nonlinear whispering-gallery mode resonator with an ultra-high $Q$ factor is pumped by a resonant continuous-wave laser around 1500 nm where the overall dispersion of the resonator is anomalous. The spectrum of the output signal, which above a certain threshold is a Kerr comb, can be monitored using an optical spectrum analyzer. $^{22,23}$ The resonances can be monitored as well using an oscilloscope when the laser frequency is scanned.  
At the theoretical level, the dynamics of the intracavity laser field is generally investigated with the following dimensionless Lugiato-Lefever equation  
$$
\frac{\partial\psi}{\partial\tau}=-(1+i\alpha)\psi+i|\psi|^{2}\psi-i\frac{\beta}{2}\frac{\partial^{2}\psi}{\partial\theta^{2}}+F,
$$  
where $\begin{array}{r}{\psi(\theta,\tau)=\sum_{l}\psi_{l}(\tau)e^{i l\theta}}\end{array}$ is the intra-cavity field, $\psi_{l}$ is the field in the mode of reduced azimuthal order $\it{l}$ $\tau$ is the dimensionless time, $\theta\in[-\pi,\pi]$ is the azimuthal angle of the disk-resonator, $\alpha$ stands for laser detuning with regards to the resonance of the pumped mode, $\beta$ stands for dispersion, and $F$ is the pump field. Depending  
on the parameters, various kinds of combs can be excited, as comprehensively reviewed in the literature. $^{9-13}$ In particular, all stationary Kerr combs are symmetrical with regards to the pump and the output signal . can be explicitly written as  
$$
\begin{array}{r c l}{{\psi_{\mathrm{out}}}}&{{=}}&{{\displaystyle\sum_{l}\psi_{\mathrm{out},l}e^{i l\theta},}}\\ {{}}&{{}}&{{}}\\ {{}}&{{=}}&{{\displaystyle\psi_{\mathrm{out,0}}\left[1+\sum_{l>1}2m_{l}e^{i\xi_{l}}\cos\left(l\Omega_{\mathrm{FSR}}t+\frac{1}{2}\Delta\phi_{l}\right)\right],}}\end{array}
$$  
where $\psi_{\mathrm{out},l}$ is the modal output field in the mode $l$ $m_{l}=|\psi_{\mathrm{out,}\pm l}|/|\psi_{\mathrm{out,0}}|$ is the sidemode-to-pump ratio, and $\Omega_{\mathrm{{FSR}}}$ is the free-spectral range of the resonator. The parameter $\xi_{l}$ is a constant that only depends on the parameters of the system, while the phase shift $\Delta\phi_{l}$ depends on the initial conditions.  
The microwave signal at the output of the photodetector is proportional to  
$$
|\psi_{\mathrm{out}}|^{2}=\frac{1}{2}\mathcal{M}_{0}+\sum_{n=1}^{+\infty}\left[\frac{1}{2}\mathcal{M}_{n}\exp(i n\Omega_{\mathrm{FSR}}t)+\mathrm{c.c.}\right],
$$  
where  
$$, The Talbot effect has been described for the first time in 1836 as a peculiar phenomenon observed in the near field of an optical grating. Summing over contributions of the individual rulings to the total field in the Fresnel approximation, a term of the form $\exp(-i k l^{2}a^{2}/2z)$ appears with the wave number $k$ , the rulings numbered by $l$ and spaced by $a$ and the distance from the grating z. Summing over $\mathbf{\xi}_{l}$ generally yields a rather chaotic intensity distribution. Talbot noted though that all these terms reduce to $\exp(-i2\pi l^{2})=1$ at a distance of $z=k a^{2}/4\pi$ . The remaining terms add up to the intensity at $z=0$ provided that this intensity is periodic with $a$ [1]. The same phenomenon can be observed in the time domain with a periodic pulse train signal that is subject to group velocity dispersion $\phi^{\prime\prime}$ that provides the quadratic phase evolution. The pulses first spread out in time, an then reassemble after propagation the distance $t_{r}^{2}/2\pi|\phi^{\prime\prime}|,$ where $t_{r}$ is the pulse repetition time [2, 3]. The same behaviour should be observable with a single pulse that is on a repetitive path in an optical cavity. In contrast to a free space pulse train, higher order dispersion is required as we will show below., The addition of other driving fields can be introduced in a single Lugiato-Lefever equation (LLE) accounting for their phase and azimuthal offsets30. Although this multipump LLE approach captures the KIS phenomenon', it can be challenging to study the different colours individually as they are all included in the single cavity field. Instead, one can obtain a system of nonlinearly coupled LLEs accounting for the DKS field $a_{\mathrm{dks}}$ and phase-offset second colour $a_{\mathrm{sec.}}$ both driven by their respective pump $P_{\mathrm{main}}$ and $P_{\mathrm{aux}}$ . Such formalism enables the re-normalization of their respective phase and allows study of each colour independently (see Methods for the derivation):  
$$
\begin{array}{r l}&{\frac{\partial a_{\mathrm{dks}}}{\partial t}=\left(-\frac{\kappa}{2}+\mathrm{i}\delta\omega_{\mathrm{main}}\right)a_{\mathrm{dks}}+\mathrm{i}\Sigma_{\mu}D_{\mathrm{int}}(\mu)A_{\mathrm{dks}}\mathrm{e}^{\mathrm{i}\mu\theta}}\\ &{\qquad-\mathrm{i}\gamma L(|a_{\mathrm{dks}}|^{2}+2|a_{\mathrm{sec}}|^{2})a_{\mathrm{dks}}}\\ &{\qquad+\mathrm{i}\sqrt{\kappa_{\mathrm{ext}}P_{\mathrm{main}}}}\end{array}
$$  
$$
\begin{array}{r l}&{\frac{\partial a_{\mathrm{sec}}}{\partial t}=\left(-\frac{\kappa}{2}+\mathrm{i}\delta\omega_{\mathrm{aux}}-\mathrm{i}D_{\mathrm{int}}(\mu_{\mathrm{aux}})\right)a_{\mathrm{sec}}}\\ &{\qquad+\mathrm{i}\Sigma_{\mu}D_{\mathrm{int}}(\mu)A_{\mathrm{sec}}\mathrm{e}^{\mathrm{i}\mu\theta}}\\ &{\qquad-\mathrm{i}\gamma L(2|a_{\mathrm{dixs}}|^{2}+|a_{\mathrm{sec}}|^{2})a_{\mathrm{sec}}}\\ &{\qquad+\mathrm{i}\sqrt{K_{\mathrm{ext}}P_{\mathrm{aux}}}\mathrm{e}^{\mathrm{i}\mu_{\mathrm{aux}}\theta}}\end{array}
$$, source_sentence: What effect does switching on the second pump have on the pulses of the Kerr frequency comb?
sentences: The first time-domain characterization of Kerr combs was performed through spectral line-by-line shaping of frequency combs generated in normal dispersion $\mathrm{Si}_{3}\mathrm{N}_{4}$ microrings [31]. The experimental scheme is shown in Figure 10. A pulse shaper based on a spatial light modulator [8o] is used to tailor the amplitude and phase of each comb line after the microring. The waveform after shaping is diagnosed by measuring the second-order intensity autocorrelation [60]. In the line-by-line shaping procedure, the comb lines are selected one by one to pass through the pulse shaper. The phase shift applied to each comb line is optimized to maximize the second-harmonic strength at zero time delay. In this way, if the comb lines from the microring maintain a time-invariant relative phase profile (i.e., high coherence), their phases will be compensated to a uniform state after the pulse shaper, forming transform-limited pulses in the time domain. In contrast, transform-limited pulses cannot be obtained for lowcoherence combs. A similar scheme was also employed in [32] to characterize the time-domain behavior of frequency combs from a fused quartz microresonator., As we discussed in Section 3, the train of optical pulses corresponding to the mode-locked Kerr frequency comb can be synchronized with the beatnote between the Dw, generated because of the specific frequency-dependent GVD of the resonator, and the pump light. The DW and the frequency comb are generated simultaneously, so it is hard to study their synchronization mechanism. In this section, we consider a different situation and introduce a second Cw pump harmonic to a resonator characterized by an ideal quadratic anomalous GVD. We provide numerical simulation results which support the idea rendered in Figure 1, i.e., locking the comb supported by the main pump (Pump 1) to the second pump (Pump 2) through tuning the frequency of Pump 2. Pump 2 resembles a DW, however it can be added after the Kerr frequency comb is formed. We see that the Kerr comb generated initially corresponds to a train of dissipative solitons having arbitrary relative positions. Switching the second pump on results in shifting the pulses to the positions defined by the beatnote between Pumps 1 and 2, and in the synchronization of the frequency comb with the beatnote signal of the pump waves. In this case, the phase locking of the microcomb to the second pump can be explained by the dynamic interaction of the pulse with the Cw background modulation since the time scale of the modification of the frequency comb can be longer compared to that of establishing steady state for the second pump in the resonator. The locking also results in modified repetition rate of the frequency comb, similar to the cases studied in the previous section., Abstract: Microresonator-based optical frequency combs have been greatly developed in the last decade and have shown great potential for many applications. A dual-comb scheme is usually required for lidar ranging, spectroscopy, spectrometer and microwave photonic channelizer. However, dual-comb generation with microresonators would require doubled hardware resources and more complex feedback control. Here we propose a novel scheme for dual-comb generation with a single laser diode self-injection locked to a single microresonator. The output of the laser diode is split and pumps the microresonator in clockwise and counter-clockwise directions. The scheme is investigated intensely through numerical simulations based on a set of coupled Lugiato-Lefever equations. Turnkey counter-propagating single soliton generation and repetition rate tuning are demonstrated., source_sentence: What is required to access soliton states in terms of the pump laser frequency tuning direction?
sentences: To gain further insights into the CW and CCW fields, we define modified detuning as the frequency difference between the pump laser and the XPM shifted resonance, given by  
$$
\Delta\omega_{\mathrm{mod,CW}}=\Delta\omega-(2-f_{R})P_{\mathrm{CCW}}
$$  
$$
\Delta\omega_{\mathrm{mod,CCW}}=\Delta\omega-(2-f_{R})P_{\mathrm{CW}}
$$  
where $P_{\mathrm{CCW}}={\overline{{|B|^{2}}}}$ and $P_{\mathrm{CW}}={\overline{{|A|^{2}}}}$ are the average power in the corresponding directions. By substituting the modified detunings into Eqs. (4) and (5), the equations become a form similar to the unidirectionally driven Lugiato-Lefever equation [31].  
For a general model with unidirectional pump, the soliton peak power is mainly determined by the cold cavity detuning [31,32]. A larger detuning corresponds to a higher soliton peak power. As illustrated in Fig. 4, if the CW direction has a larger pump power than the CCW direction, the CW intracavity power will be higher, i.e., $P_{\mathrm{CW}}{>}P_{\mathrm{CCW}}$ . Thus the modified detuning $\Delta\omega_{\mathrm{mod,CW}}{>}\Delta\omega_{\mathrm{mod,CCW}}$ . As a consequence, the soliton peak power in the CW direction becomes larger than that in the CCW direction. Therefore, by tuning the MZI to change the pump splitting ratio, different modified detunings are introduced in the CW and CCW directions through the XPM effect, leading to different soliton peak power in the two directions. The evolution of the average intracavity power and soliton peak power shown in Figs. 3(i) and 3(j) is consistent with the above analysis. To further validate the conclusion, we run simulations with different pump spliting ratios and calculate the modified detunings. Figure 5(a) illustrates the relationship between the pump splitting ratio and the modified detuning. Figure 5(b) illustrates the relationship between the soliton peak power and the modified detuning. Due to symmetry, the curves are degenerated in the CW and CCW directions.  
It has been known that the soliton group velocity and repetition rate can be changed due to Raman induced soliton self-frequency shift [17]. Therefore, the different soliton peak power in the CW and CCW directions will cause different Raman self-frequency shifts and different soliton repetition rates. Theoretically, the normalized repetition rate difference is related to the detuning by [17]  
$$, microcomb into a THz wave. The optical power of the auxiliary light is monitored by a third photodiode (not shown in Fig. 1(a)). The frequency of the auxiliary laser is tuned into its resonance from the blue detuned side and fixed on the blue side of the resonance. Note that, the auxiliary laser is free-running without feedback control on the laser frequency or the power during the soliton generation. By optimizing the laser detuning and optical power of the auxiliary laser, soliton states can be accessed by slowly tuning the pump laser frequency into a soliton regime from the blue detuned side. A detailed description of the soliton generation process can be found in the Ref. [21]., $$  
where the overdot indicates the time derivative. Note that higher-order dispersion at arbitrary order can be accounted for by replacing $\zeta_{2}l^{2}/2$ by $\scriptstyle\sum_{n=2}^{n_{\mathrm{max}}}\zeta_{n}l^{n}/n!$ . which is obtained from Eq. (1). Without loss of generality, we can arbitrarily consider the phase of the external pump field as a reference and set it to zero, so that this field becomes real valued and can be written as  
$$
\mathcal{A}_{\mathrm{in}}\equiv A_{\mathrm{in}}=\sqrt{\frac{P}{\hbar\omega_{\mathrm{L}}}}.
$$  
It is important to recall the normalization in the semiclassical Eqs. (4) is such that $\vert\mathcal{A}_{l}\vert^{2}$ is a number of photons (cavity fields), while $|A_{\mathrm{in}}|^{2}$ is a number of photons per second (propagating fields). This normalization is physically the most appropriate at the time to perform the canonical quantization.
pipeline_tag: sentence-similarity
library_name: sentence-transformers
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Created: 2025-09-16 03:14:53