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In this paper, a polarization beam splitter (PBS) based on the gold wire-filled dual-core photonic crystal fiber is proposed. The full-vector finite element method is used to investigate the influe...

In this paper, we propose a photonic crystal fiber (PCF) refractive index (RI) sensor based on the surface plasmon resonance (SPR) effect. The coupling and sensing characteristics of the proposed P...

In this paper, passive generation of the multi-wavelength parabolic pulses (PPs) in tapered silicon nanowires (TSNs) is numerically investigated. The coupled inhomogeneous nonlinear Schrödinger equation (INLSE) is derived in the context of TSN to model the multi-wavelength PP generation. The TSN is designed based on the well-known self-similar theory that the group-velocity dispersion is decreased while the nonlinear coefficient is unchanged along the propagative direction. While the pump wavelengths for three input pulses are specially set with equal intervals of 18, 12, and 6 nm, the time-domain profiles are aligned at the same position. Simulation results show that except for wavelength interval, the waveguide length is also a critical factor that influences the quality of generated PP. Both of them reshape the pulse profile by the means of walk-off effect which depends on the cross-phase modulation between multiple pulses. By properly optimizing the input parameters of Gaussian pulses as well as the center wavelength interval and TSN length, we prove that the generation of two- even three-wavelength PPs with high-quality is feasible.

We propose the two-stage cascaded-tapered silica photonic crystal fiber (PCF) for the supercontinuum (SC) generation. The cascaded-tapered silica PCF is designed to have a spatial periodic structure. The physical scenarios of the spectral broadening due to the interaction between the structure-induced periodic dispersion and Kerr nonlinearity under different pulse widths and peak powers are investigated. It is found that when the pump pulses with width of

A broadband polarization beam splitter (PBS) based on compressed hexagonal structure and liquid crystal-filled dual-core photonic crystal fiber is proposed. The bandwidth of the proposed PBS is 280 nm, covering the S, C, L, and U communication bands. Besides, it has a short length of 109.5 µm and an extinction ratio of 63 dB at the communication wavelength of 1.55 µm.

An ultra-short polarization beam splitter (PBS) based on a dual-core photonic crystal fiber (PCF) with the surface plasmon resonance effect is proposed. The finite-element method is used to investigate the coupling characteristics between the core mode and surface plasmon polariton mode. The influences of the PCF structure parameters on the coupling length and coupling length ratio are also investigated. The normalized output powers of the x-polarization and y-polarization are calculated, and the optimized PBS achieves an ultra-short length of 62.5 μm. The splitting bandwidth of 110 nm (1.51 to 1.61 μm) is achieved when the extinction ratio (ER) is less than −20 dB. The minimum ER reaches −71 dB at the wavelength of 1.55 μm. The proposed PBS has an important application in high-speed optical communication systems.

In this paper, a V-shape photonic crystal fiber (PCF) polarization filter based on surface plasmon resonance (SPR) effect is proposed. With the full vector finite element method, the V-shape photonic crystal fiber polarization filter is designed, and the coupling characteristics between the core mode and surface plasmon polariton mode are analyzed. The simulation results show that the fiber parameters have significant effects on the shift and strength of the SPR wavelength. Moreover, the losses of the core modes along the Y and X polarization directions are 68904 dB/m and 858 dB/m at the SPR wavelength of 1550 nm, respectively. Finally, the extinction ratio and error-tolerant rate of extinction ratio are also analyzed. The proposed V-shape PCF polarization filter can achieve good filtering effect in the communication band and is easy to integrate with existing optical fiber communication and sensing systems.

In this paper, we numerically investigate the generation of parabolic pulse (PP) in a silicon waveguide taper with simultaneous variations of the group-velocity dispersion and nonlinearity along the propagation direction. The design of such a waveguide taper is based on the condition of self-similar propagation of the PP. When Gaussian, hyperbolic secant, and super-Gaussian pulses are propagated inside the waveguide taper designed, the evolution processes under the ideal condition are analyzed. Then the PP generation from Gaussian input is shown when higher-order dispersion, higher-order nonlinearity, linear loss, two-photon absorption, free-carrier absorption, and free-carrier dispersion are taken into account. Moreover, the influences of the initial chirp, pulse width, peak power, and waveguide length on the PP generation are further discussed. It is demonstrated that high-quality PP can be obtained with a mismatch parameter as low as 1 . 3 × 1 0 − 3 , in the designed silicon waveguide taper.

In this paper, we numerically demonstrate efficient spectral compression (SPC) of wavelength-shifting soliton in a chalcogenide strip waveguide. It is found that the profiles of group-velocity dispersion (GVD) and Kerr nonlinearity play key roles in determining SPC. After calculating the dispersion of Kerr nonlinearity and Raman spectrum for three kinds of chalcogenide materials, Ge11.5As24Se64.5 is chosen as the material for designing the chalcogenide strip waveguide (CSW). The geometric parameters of CSW are optimized to obtain the desired GVD and Kerr nonlinearity. Simulation results show that in the designed CSW, an input spectrum width of 52.04 nm can be compressed to 7.23 nm along with wavelength shift of 17 nm when the input peak power is 25 W. With the input peak power increasing to 75 W, the SPC is slightly weakened, but wavelength shift can be up to 190 nm. The proposed CSW is applied to integrated all-optical quantization and an effective quantization number of 3.66-bit is achieved. It is expected that our research results can find important applications in on-chip integrated spectroscopy, all-optical signal processing, etc.

A polarization beam splitter (PBS) based on dual-core photonic crystal fiber (DC-PCF) with three layers of elliptical air holes is proposed. The full-vector finite element method is used to investigate the coupling and propagation characteristics of the PBS, and the three-dimensional beam propagation method is used to demonstrate the evolutions of the x-pol and y-pol light fields in cores A and B of the DC-PCF. In this design, the elliptical air holes are introduced to enhance the birefringence of the DC-PCF. The simulation results show that, with the proposed PBS, the complete beam splitting can be achieved at wavelength 1.55 μm when the fiber length is 254 μm. Moreover, when the extinction ratio is less than −20 dB, the bandwidth of the PBS can be up to 48 nm, covering the whole C-band. It is believed that the proposed PBS will be a promising candidate in laser and sensor systems.

An ultra-short and broadband dual-core photonic crystal fiber polarization beam splitter with a gold film based on surface plasmon resonance effect is proposed. The splitter length and bandwidth are 194 μm and 243 nm, respectively.

An ultra-broadband silicon dual-core photonic crystal fiber polarization beam splitter at mid-infrared spectral region based on surface plasmon resonance is proposed. The bandwidths of the cores A and B are 730 and 580 nm, respectively. © 2020 The Author(s).

We design a dual-core photonic crystal fiber (PCF) polarization beam splitter (PBS) based on surface plasmons resonance effect. The maximum extinction ratio of the PBS can be up to -160.56 dB at wavelength 1.55 μm.

In this paper, a chalcogenide-based ridge waveguide with a suspended structure on the substrate of Si 3 N 4 , is designed, which is demonstrated to have low and flat dispersion profiles. Simulation results show that when the higher-order nonlinear effects and linear loss are considered, a broadband supercontinuum with high coherence ranging from 1.0 to 5. 6 μ m is obtained after a 3.1-mm long propagation when pumping wavelength 2. 65 μ m and peak power 450 W. Our proposed scheme provides a promising solution to realize broadband and highly coherent SC in mid-infrared region for nonlinear photonics and spectroscopy.

In this paper, we propose a double-layer dielectric loaded graphene plasmonic ridge waveguide (DLGPRW) using higher-order modes for biochemical sensing. The simulation results show that the propagation length and the sensing sensitivities are greatly improved.

In this paper, we propose two-stage cascaded photonic crystal fiber tapers for the supercontinuum (SC) generation. The nonlinear evolution of the SC generation is numerically investigated when pump pulses with different peak powers are used.

In this paper, we propose an all normal dispersion silicon nitride waveguide for optical quantization. The results show that a 6-bit quantization resolution is successfully achieved with an effective number of bit of 5.978 bit.

The quenching and cooling effects upon luminescence of Bi/Er co-doped fiber (BEDF) have been investigated. The bismuth related luminescence has significantly been enhanced by quenching and cooling with generation of new luminescent centers.

In this paper, the conditions of the self-similar propagation of the parabolic pulse (PP) in passive nonlinear tapers are derived and classified into the three cases. Analytical solutions of the inhomogeneous nonlinear Schrodinger equation (INLSE) for the three cases are obtained. Numerical verifications of these analytical solutions are demonstrated by designing the silicon waveguide tapers. Moreover, we further design three kinds of cascaded silicon waveguides for realizing the PP generation and compression. The PP compression occurs at the anomalous-dispersion segment of the cascaded silicon waveguide. The generalized INLSE is used to model the generation and compression of the PP. When considering the higher order dispersion, higher order nonlinearity, and losses, the complex nonlinear dynamics are investigated. Simulation results show that a 300-fs Gaussian input pulse can evolve to the PP and be compressed to 35.6 fs in the cascaded silicon waveguide.

In this paper, we theoretically investigate the supercontinuum generations (SCGs) in a carbon disulfide (CS 2 )-core photonic crystal fiber (PCF). We show that the intrinsic slow nonlinearity of CS 2 plays a significant role to control the soliton fission process. The initiation of the soliton fission process can be distinctly delayed. More importantly, the transition between the smooth soliton fission and the sub-solitons’ chaotic-like interference is sufficiently extended so that the optical spectrum can keep broadening continuously while still maintaining a smooth spectral profile. When pumping a designed CS 2 -core PCF at wavelength $1.55~\mu \text{m}$ in the anomalous dispersion region, we obtain temperature-controllable and highly coherent SCs spanning over one octave at the −30-dB spectral intensity. The unique feature of large slow nonlinearity and the controllable dispersion and nonlinearity of CS 2 -core PCF confirm that as a versatile platform for highly coherent and octave-spanning SCGs.

In this paper, we propose and design a chalcogenide (As2S3)-based slot waveguide taper with exponentially decreasing dispersion profile to realize high-degree pulse compression of low-power chirped solitons. Based on the waveguide taper designed, pulse compression of fundamental solitons, and chirped 2-soliton breather are both investigated numerically. With self-similar pulse compression scheme, a 1 ps input pulse is compressed to 81.5 fs in 6 cm propagation. By using 2-soliton breather pulses, a 1 ps chirped pulse is compressed to 80.3 fs in just 2.54 cm. This is the first demonstration of the feasibility of high-degree nonlinear pulse compression in As2S3-based slot waveguide taper.

Second-harmonic generation (SHG) near ultraviolet wavelengths is experimentally demonstrated by coupling femtosecond pump pulses into the normal dispersion region far away from the zero-dispersion wavelength of the fundamental mode in a silica photonic crystal fiber (PCF) fabricated in our laboratory. When the pump pulses with average input power $P_{\mathrm {av}}$ of 500 mW and center wavelength $\lambda _{\mathrm {p}}$ of 820 nm are used, the maximum conversion efficiency $\eta _{\mathrm {SH}} ^{^{^{}}}$ of the second harmonics centered at 410 nm can be up to $1.6\times 10^{-6}$ , corresponding to the output power $P_{\mathrm {SH}}$ of 520 nW. By measuring $P_{\mathrm {SH}}$ at different PCF lengths and studying the temporal dependence of $P_{\mathrm {SH}}$ , it is confirmed that the physical mechanism of SHG is dominated by surface nonlinearity polarization, which is resulted from the local inhomogeneities in the silica core region and at the core-air-silica cladding interface of PCF. Finally, a theoretical model is established to analyze the nonlinear optical process.

A novel light source for coherent anti-Stokes Raman scattering (CARS) microspectroscopy based on degenerate four-wave mixing (DFWM) is experimentally demonstrated in a photonic crystal fiber with two adjacent zero dispersion wavelengths. When the pump pulse wavelengths are changed from 780 to 800 nm and the average input powers $P_{{\mathrm{av}}}$ are increased from 300 to 500 mW, the central wavelengths $\lambda _{\mathrm{as}}$ and $\lambda _{s}$ of the generated anti-Stokes and Stokes waves are tunable from 660 to 606 nm and 953 to 1177 nm, respectively. In addition, the corresponding frequency difference between the pump and Stokes beams is in the range of 2331–4002 cm $^{-1}$ , which covers a wide range of vibrational Raman spectra of the biological and chemical samples. The feasibility of the proposed DFWM-based light source is demonstrated through measuring the CARS spectrum of the ethanol sample.

In this paper, a novel silicon dual-core photonic crystal fiber (Si-DC-PCF) polarization beam splitter (PBS) based on the surface plasmon resonance effect is proposed. The mode-coupling characteristics between the X - and Y -polarized even and odd modes and surface plasmon polariton mode are analyzed by using the finite-element method and coupled-mode theory. The influences of the structure parameters of the Si-DC-PCF on the coupling length and coupling length ratio are investigated. The normalized output power of the X - and Y -polarized modes in cores A and B and the corresponding extinction ratio are also discussed. By optimizing the structure parameters of the Si-DC-PCF, the PBS length of 192 µm and bandwidth of 830 and 730 nm in cores A and B are achieved. It is believed that the proposed Si-DC-PCF PBS can find important applications in mid-infrared laser and sensing systems.

A novel plasmonic polarization filter based on the diamond-shape photonic crystal fiber (PCF) is proposed. The resonant coupling characteristics of the PCF polarization filter are investigated by the full-vector finite-element method. By optimizing the geometric parameters of the PCF, when the fiber length is 5 mm, the polarization filter has a bandwidth of 990 nm and an extinction ratio (ER) of lower than –20 dB. Moreover, a single wavelength polarization filter can also be achieved, along with an ER of –279.78 dB at wavelength 1.55 μm. It is believed that the proposed PCF polarization filter will be very useful in laser and optical communication systems.

The extreme computational complexity in generating a hologram makes the interactive holographic display very difficult. An optimized layered rendering method for real-time interactive holographic display based on ray-tracing technique is presented in order to overcome this challenge and realize real-time interaction of three-dimensional scenes. Ray tracing is able to render more complex and photorealistic images for different illuminations and circumstances. Rays are launched in parallel and traced to obtain ray–object intersections, and then the complex wave field of the effective pixels in different layers is determined. The occlusions between different layers are also considered to effectively reduce the overall computation. A computer-generated hologram is fused with the multilayer-hologram-diffraction results using the layered fast Fourier transform algorithm. The experimental results demonstrate the effectiveness of the proposed method. The reconstructed holographic image with real depth cues is demonstrated by the experiments, and the optical reconstruction images can be interacted in real-time.

In integral imaging, the quality of a reconstructed image degrades with increasing viewing angle due to the wavefront aberrations introduced by the lens-array. A wavefront aberration correction method is proposed to enhance the image quality with a pre-filtering function array (PFA). To derive the PFA for an integral imaging display, the wavefront aberration characteristic of the lens-array is analyzed and the intensity distribution of the reconstructed image is calculated based on the wave optics theory. The minimum mean square error method is applied to manipulate the elemental image array (EIA) with a PFA. The validity of the proposed method is confirmed through simulations as well as optical experiments. A 45-degree viewing angle integral imaging display with enhanced image quality is achieved.

The bending response of polymer optical fibre Bragg grating (POFBG) and silica optical fibre Bragg grating (SOFBG) mounted on a brass beam have been systematically studied and compared. The results indicate that POFBG has higher (almost twice as much) bend sensitivity than SOFBG. Based on the difference between the bend and temperature sensitivity of POFBG and SOFBG, a new method of measuring vector bend and temperature simultaneously was proposed by using a hybrid sensor head with series connection of one POFBG and one SOFBG with different Bragg wavelengths. It provides high sensitivity and resolution for sensing bend and temperature changes simultaneously and independently. The proposed sensor can find some applications in the fields where high sensitivity for both bend and temperature measurements are required.

In this paper, we describe an all-optical quantization scheme for analog-to-digital conversion, which is realized by slicing the supercontinuum spectrum with filters. We experimentally demonstrate a 3-bit all-optical quantizer.

Kerr soliton frequency comb generation in monolithic microresonators recently attracted great interests as it enables chip-scale few-cycle pulse generation at microwave rates with smooth octave-spanning spectra for self-referencing. Such versatile platform finds significant applications in dual-comb spectroscopy, low-noise optical frequency synthesis, coherent communication systems, etc. However, it still remains challenging to straightforwardly and deterministically generate and sustain the single-soliton state in microresonators. In this paper, we propose and theoretically demonstrate the excitation of single-soliton Kerr frequency comb by seeding the continuous-wave driven nonlinear microcavity with a pulsed trigger. Unlike the mostly adopted frequency tuning scheme reported so far, we show that an energetic single shot pulse can trigger the single-soliton state deterministically without experiencing any unstable or chaotic states. Neither the pump frequency nor the cavity resonance is required to be tuned. The generated mode-locked single-soliton Kerr comb is robust and insensitive to perturbations. Even when the thermal effect induced by the absorption of the intracavity light is taken into account, the proposed single pulse trigger approach remains valid without requiring any thermal compensation means., Comment: 8 pages, 6 figures

In this paper, we design a tapered tellurite photonic crystal fiber (TTPCF) with nonlinear coefficient increasing along the propagation direction, and demonstrate the mid-infrared self-similar pulse compression of the fundamental soliton in such a TTPCF. When the variation of group-velocity dispersion, higher-order dispersion, higher-order nonlinearity, and linear loss are considered, a 1 ps pulse at wavelength 2.5 μm can be compressed to 62.16 fs after a 1.63-m long propagation, along with the negligible pedestal, compression factor Fc of 16.09, and quality factor Qc of 83.16%. Then the compressed pulse is launched into another uniform tellurite PCF designed, and highly coherent and octave-spanning supercontinuum (SC) is generated. Compared to the initial picosecond pulse, the compressed pulse has much larger tolerance of noise level for the SC generation. Our research results provide a promising solution to realize the fiber-based mid-infrared femtosecond pulse source for nonlinear photonics and spectroscopy.

Photonic time stretched analog-to-digital converter (PTS-ADC) utilizes a broadband optical source and dispersion medium to expand the capabilities of electrical digitizers, achieving real-time sampling with high resolution. In order to minimize used fiber length and simplify PTS-ADC equipment, large dispersion photonic crystal fiber (PCF) is used as dispersion medium. In this letter we demonstrated the impact of optical nonlinearity on PTS-ADC based on large dispersion PCF performance as compared with single mode fiber (SMF) and dispersion compensation fiber (DCF). It is stimulated that dispersion penalty null frequency of fundamental tone will shift using three fibers when nonlinearity is added. In comparison, SMF is most insensitivity by changing input optical power, then PCF. However PCF is most insensitive by changing pulse width. Meanwhile, PCF is best to suppress 3rd-order harmonic distortion according to carrier-to-interference ratio (CIR) in three fibers. PCF is the most suitable as broadening medium in PTS-ADC.

In this paper, we optimize a proposed 6-bit all-optical quantization approach based on soliton self-frequency shift (SSFS) and spectral compression techniques. A 10 m-long high nonlinear photonic crystal fiber (PCF) is still used as an SSFS medium relevant to the power of the sampled optical pulses. Furthermore, a 10 m-long dispersion flattened hybrid cladding hexagonal–octagonal PCF (6/8-PCF) is utilized as a spectral compression medium to realize resolution enhancement after positive or negative pre-chirp process. Simulation results show that the 6-bit quantization is still obtained when a 100 m-long dispersion-increasing fiber (DIF) is replaced by a hybrid cladding 6/8-PCF in spectral compression module.

In this paper, an Ytterbium-doped V-shape photonic crystal fiber (Yb-VPCF) with low dispersion and high nonlinearity is designed and fabricated in our laboratory. Through coupling femtosecond pulses into the fundamental mode of Yb-VPCF, the tunable anti-Stokes signals at the visible wavelength are efficiently generated based on the phase-matching four-wave mixing. When the pump wavelength is changed from 810, to 820, and to 830 nm and the input average power is increased from 0.4, to 0.5, and to 0.6 W, respectively, the anti-Stokes signals are generated within the wavelength range of 562–477 nm. The wavelength-tunable range is over 100 nm, and the maximum power ratio of anti-Stokes signal at 477 nm and the residual pump at 830 nm can be up to 23.9:1. The anti-Stokes signals generated can be used as the ultrashort pulse sources for ultrafast optoelectronics and spectroscopy.

A stable three-channel dual-wavelength fiber ring laser is proposed and experimentally demonstrated. The digital micromirror-device (DMD) processor can select and recirculate any dual waveband from the gain spectrum of the erbium-doped fiber at each channel. The uniform and stable dual-wavelength oscillation is obtained by a highly nonlinear photonic crystal fiber, which causes two degenerate the four-wave-mixing processes. By loading different reproducibility diffraction gratings on the optoelectronic DMD processor, the laser can be operated stably in a three-channel dual-wavelength scheme at room temperature. The power fluctuation of each laser channel is less than -0.02 dB.

We propose a novel scheme for synchronous optical sampling based on multicast parametric process. The linearly chirped and time-broadened pulses are utilized to replace the traditional mode-locked sampling pulses. An optical sampling rate of 80 Gbit/s is realized by using only one sampling source with repetition rate of 10 GHz.

In this Letter, we demonstrate experimentally for the first time, to the best of our knowledge, discrete ultraviolet (UV) wavelength generation by cascaded intermodal FWM when femtosecond pump pulses at 800 nm are launched into the deeply normal dispersion region of the fundamental guided mode of a multimode photonic crystal fiber (MPCF). For pump pulses at average input powers of Pav=450, 550, and 650 mW, the first anti-Stokes waves are generated at the visible wavelength of 538.1 nm through intermodal phase matching between the fundamental and second-order guided mode of the MPCF. The first anti-Stokes waves generated then serve as the secondary pump for the next intermodal FWM process. The second anti-Stokes waves in the form of the third-order guided mode are generated at the UV wavelength of 375.8 nm. The maximum output power is above 10 mW for Pav=650 mW. We also confirm that the influences of fiber bending and intermodal walk-offs on the cascaded intermodal FWM-based frequency conversion process are negligible.

A simple vector bend sensing scheme based on polymer and silica fiber Bragg gratings is proposed. A high sensitivity of 0.937 nm/m−1 can be obtained in the curvature range of −4.2 to 4.2 m−1 and the bend orientation is distinguishable.

Parabolic pulses have important applications in both basic and applied sciences, such as high power optical amplification, optical communications, all-optical signal processing, etc. The generation of parabolic similaritons in tapered hydrogenated amorphous silicon photonic wires at telecom (λ ~ 1550 nm) and mid-IR (λ ≥ 2100 nm) wavelengths is demonstrated and analyzed. The self-similar theory of parabolic pulse generation in passive waveguides with increasing nonlinearity is presented. A generalized nonlinear Schrödinger equation is used to describe the coupled dynamics of optical field in the tapered hydrogenated amorphous silicon photonic wires with either decreasing dispersion or increasing nonlinearity. The impacts of length dependent higher-order effects, linear and nonlinear losses including two-photon absorption, and photon-generated free carriers, on the pulse evolutions are characterized. Numerical simulations show that initial Gaussian pulses will evolve into the parabolic pulses in the waveguide taper designed.

In this paper, we demonstrated experimentally the intermodal four-wave mixing effect by launching femtosecond pulses centered at 1550 nm into deeply normal dispersion region in the fundamental guided-mode of an air-silica photonic crystal fiber with two zero dispersion wavelengths. When intermodal phase-matching condition is satisfied, the energy of the pump waves at 1550 nm in the fundamental guided-mode is converted to the anti-Stokes waves around 1258 nm and Stokes waves around 2018 nm both in the second-order guided-mode. When femtosecond pulses at input average power P av of 90 mW are propagated inside 22-cm-long photonic crystal fiber, the conversion efficiencies η as and η s of the anti-Stokes and Stokes waves generated are 8.5% and 6.8%, respectively. We also observed that the influences of the fiber bending and walk-off effect between the fundamental and second-order guided-modes on intermodal four-wave mixing-based frequency conversion process are very small.

We numerically study parabolic similariton generation in tapered hydrogenated amorphous silicon photonic wires. Simulation results show that initial Gaussian pulses can evolve into parabolic similaritons with the linear chirp at 1550 and 2150 nm, respectively.

We demonstrate a bend sensor with a fiber Bragg grating (FBG) and ellipsoid structure. Cladding modes are excited by ellipsoid and recoupled back to the core mode by FBG. Bending curvature sensitivity is 19.78 mW/m-1.

We experimentally generate second-harmonics within deep-ultraviolet wavelength range of 334.5 to 306 nm. We combine four-wave mixing and surface nonlinearity polarization by coupling femtosecond pump pulses at ∼800 nm into an air-silica photonic crystal fiber.

A temperature-insensitive refractive index sensing based on W-type fiber grating has been proposed. We investigated the response of grating and found the intensity of resonant peaks was sensitive to refractive index and insensitive to temperature.

We investigate broadband spectral compression assisted by soliton self-frequency shift in a proposed chalcogenide strip waveguide. Simulation results show that a compression ratio of 7.2 and a wavelength shift of 190 nm can be achieved.

Higher-order solitons are formed by coupling femtosecond pulses into the fundamental mode of a highly nonlinear silica photonic crystal fiber (HNL-SPCF) fabricated in our laboratory. It is experimentally observed that the higher-order solitons break up into a series of stable and broadband discrete fundamental solitons at the mid-infrared wavelength longer than 2000 nm through the process of soliton self-frequency shift due to the perturbations induced by the higher-order dispersive and nonlinear effects. The maximum soliton red-shift and the tunable wavelength range can be up to 1600 nm and over 400 nm, respectively. The nonlinear dynamic processes of femtosecond pulse breakup are consistent with the solution of the generalized nonlinear Schrodinger equation. This multiple stable and broadband mid-infrared wavelengths generated in such an HNL-SPCF can be used as all-fiber multiwavelength ultrashort pulse sources for multiphoton microscopy and ultrafast photonics.

In this paper, a novel compact Bragg reflector and high- Q micro-cavity based on dielectric-loaded surface plasmon polariton waveguide (DLSPPW) are proposed. The Bragg reflector is formed by a finite array of periodic variations in the dielectric materials of the DLSPPW. The simulation results show that the proposed Bragg reflector has a much lower loss compared to conventional metal–insulator–metal (MIM) plasmonic Bragg reflectors at the expense of relatively loosen mode size. In addition micro-cavity formed by introducing a defect within the Bragg grating is also investigated, whose quality factor can reach as high as 774 at the wavelength of 1550 nm.

The broadband blue-shifted dispersive waves (DWs) are efficiently generated by the diffraction-arrested solitons in a photonic crystal fiber (PCF) designed and fabricated in our laboratory. By optimizing the pump parameters and the fiber length, the DWs can be used as the pump pulses for the high resolution coherent anti-Stokes Raman scattering (CARS) microscopy. The CARS microscopy based on the broadband DWs can be an attractive tool for simultaneously measuring the vibrational dephasing times of multiple Raman modes of the biological and chemical samples with the C–H and O–H stretch vibration resonances of 2700–3000 cm−1 and 3000–3750 cm−1.

We propose and demonstrate a high-rate all-optical sampling scheme for real-time capture of ultrafast data signals, beyond the bandwidths achievable by electronics. This scheme uniquely combines photonic time-stretch technique to slow down the ultrafast data signals with four-wave mixing to realize all-optical sampling. Real-time recording of 40 Gb/spseudo-random bit stream (PRBS) are demonstrated with a stretch factor of 40 and pump rate of 40 Gb/s in experiment.

Silicon-on-insulator (SOI) waveguide devices are emerging for the realization of optical signal processing systems for the last couple of years. The recent technological advancement in silicon photonics is the main driving force at the back of these devices. Using non-linear optical phenomenon in silicon wires and their compatibility with CMOS devices provide the stage for integrated photonic devices. All-optical signal processing devices are being investigated at present, but the chip-scale solution provided by the silicon photonics is the most promising. In this research we have investigated all-optical signal processing in a 10 mm long SOI waveguide by exploiting well established coupled wave equations. We consider single pulsed pump to analyze frequency shifting by four-wave-mixing (FWM). For the wavelengths 20⿿30 nm far from the pump, the gain overcomes nonlinear losses resulting in higher frequency conversion efficiency.