Wavelength-spacing tunable multi-wavelength fiber optical parametric oscillator based on multiple four-wave mixing

We propose a wavelength-spacing tunable multi-wavelength fiber optical parametric oscillator (MW-FOPO) with a simple line cavity and one pump source based on multiple four-wave mixing (MFWM). Stable multi-wavelength lasing at room temperature is achieved due to the four-wave mixing effect and the broadband gain of the fiber optical parametric amplifier based on a highly nonlinear fiber. The wavelength spacing of the proposed MW-FOPO can be tuned by adjusting the wavelength of the pump light or the central wavelength of the fiber Bragg grating. Seventeen lasing lines with a wavelength spacing of 2.89 nm and an extinction ratio larger than 10 dB, which covers the wavelength region from 1540 to 1568 nm is demonstrated.     

Multi-wavelength fiber ring laser based on a sampled chirped fiber Bragg grating with a hybrid gain medium

The novel multi-wavelength fiber ring laser based on a sampled chirped fiber Bragg grating with a single SOA or a hybrid gain medium is demonstrated, respectively. In case of a hybrid gain medium, the SMSR improvement of ~ 5 dB was obtained when compared with the system with a single SOA. The proposed fiber laser offers advantages such as simple structure, low loss, multi-wavelength lasing lines with moderate output power.     

Ultranarrow dual-transmission-band fiber Bragg grating filter and its application in a dual-wavelength single-longitudinal-mode fiber ring laser

A fiber Bragg grating filter with ultranarrow dual-transmission bands implemented using the equivalent phase shift technique is demonstrated. A fiber ring laser that incorporates a dual-transmission-band fiber Bragg grating filter in the ring cavity is implemented. Dual-wavelength single-longitudinal-mode lasing with a wavelength spacing as small as 0.147 nm at room temperature is experimentally demonstrated.     

Multiwavelength Raman fiber lasers with equalized peak power using a sampled chirped fiber Bragg grating

Two novel multiwavelength Raman fiber lasers using a ring cavity and a linear cavity are proposed and demonstrated experimentally. Both laser configurations include a sampled chirped fiber Bragg grating used in the reflection mode. By adjusting the polarization controller (PC) in the cavities, up to ten stable lasing wavelengths with 0.8 nm spacing and equalized peak power are achieved at room temperature. It is observed that the output spectrum depends upon which port of the grating is connected to the cavity. These two fiber ring lasers offer advantages such as, stable room temperature operation, simple structure, low loss, multiwavelength lasing lines with moderate output power. PACS 42.55.Wd; 42.55.Ye; 42.81.-i     

Multiple dual-wavelengths fiber ring laser utilizing a phase-only sampled fiber Bragg grating with multiple phase-shifts inserted

A simple technique to multiply the lasing wavelength in a semiconductor optical amplifier (SOA)-based fiber ring laser is proposed and demonstrated, which is based on the utilization of a multiple phase-shifts sampled fiber Bragg grating (FBG). Tunability for the wavelength spacing within all dual-wavelengths has also been demonstrated by changing the positions of phase-shifts. Moreover, more than 20 dual-wavelengths fiber lasers with a 3-dB linewidth of 0.017 nm and signal-to-noise ratio (SNR) of about 45 dB have been obtained.     

Multiwavelength pulse generation in semiconductor-fiber ring laser using a sampled fiber grating

A novel multiwavelength scheme has been demonstrated using a sampled fiber grating in semiconductor-fiber ring laser. By using semiconductor optical amplifier as an inhomogeneously broadened gain medium, three wavelength channels of 10 GHz are simultaneously generated. The number of the lasing channels can be changed through the polarization state adjustment in the cavity.     

光纤光栅激光器激射波长的研究

一般认为，用光纤光栅作选频元件的光纤激光器，激射波长与光纤光栅中心反射波长一致，本文报道了不同的实验研究结果。通过细致的实验研究，发现光纤光栅激光器激射波长相对于光纤光栅中心反射波长有一定的偏移。激射波长可以出现在光栅中心反射波长的长波端，也可以出现在其短波端。对不同腔结构的掺镱、掺铒光纤光栅激光器的深入研究证明，谐振腔的各向异性对激光器的激射波长偏移起到决定性的作用，波长最大偏移量主要受限于光纤光栅的反射带宽。通过激光腔内的偏振控制器改变谐振腔的各向异性，可以在光纤光栅的反射带宽内控制激射波长的位置。     

Multi-wavelength fiber ring laser based on a chirped moiré fiber grating and a semiconductor optical amplifier

A simple and cost-effective multi-wavelength fiber ring laser based on a chirped Moiré fiber grating (CMFG) and a semiconductor optical amplifier (SOA) is proposed.Stable triple-wavelength lasing oscillations at room temperature are experimentally demonstrated.The measured optical signal-to-noise ratio (SNR) reaches the highest value of 50 dB and the power fluctuation of each wavelength is less than 0.2 dB within a 1-h period.To serve as a wavelength selective element,the CMFG possesses excellent comb-like ...     

A Simple Configuration for Discontinuous Wavelength-tuning Optical Pulse Source

A simple configuration is proposed to perform wavelength switching in actively mode-locked fiber ring lasers, in which a sampled fiber Bragg grating and a tunable optical filter are cascaded in the ring cavity to exactly select the operating wavelength. The switching of four wavelengths with a spacing of 1.6 nm is obtained. The experimental results demonstrate that this technique is reliable and convenient.     

基于SOA和级联取样光纤光栅的多波长激光器

研究了基于半导体光放大器(SOA)和双段级联取样光纤光栅构成的新型结构多波长激光器.设 计了取样光纤光栅，计算了其反射谱，模拟了多波长激光器的输出光谱.基于自行制作的SOA 和取样光纤光栅，进行了多波长激光器的实验研究，得到了间隔为0.8nm、输出功率不平坦 度小于1.0dB的11个波长输出.理论和实验两个方面都可以验证：与基于普通取样光栅的多波 长方案相比，基于双段级联取样光栅的方案能改善输出谱平坦度，并可提高可激射波长数. 关键词： 半导体光放大器 取样光纤光栅 多波长激光器     

FWM-based multi-wavelength erbium-doped fiber laser using Bi-EDF

We experimentally demonstrate a simple structure but efficient multi-wavelength erbium-doped fiber laser (EDFL) using a 49 cm Bismuth-based erbium-doped fiber (Bi-EDF) as gain medium. The Bi-EDF provides erbium amplification and FWM effect in the cavity to generate a stable multi-wavelength comb operating in C-band region. We have achieved more than 5 lines with peak power of more than −35 dBm and channel spacing of 0.5 nm by incorporating a broadband fiber Bragg grating and polarization controller in the ring cavity.     

A Simple Configuration for Discontinuous Wavelength-tuning Optical Pulse Source

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Continuous True-Time-Delay System Employing a Novel Tunable Chirped Fiber Grating Delay Line and a Sampled Grating Based Multiwavelength Fiber Laser

A photonics true-time-delay system for phased array antenna beam steering employing a novel tunable chirped fiber grating delay line and a multi-wavelength erbium-doped fiber ring laser source based on a sampled grating filter is proposed. The tunable chirped fiber grating, which act as a continuous time-delay element, is achieved by bending a uniform fiber Bragg grating bonded at a slant onto the lateral surface of a simply supported beam. This technique allows the dynamic control of the chirp rate and spectral width of the grating without center wavelength shift. By adjusting the chirp rate of the fiber grating via bend strain, this kind of tunable chirped fiber grating could achieve very low and adjustable delay times, therefore provides higher angle resolution for scanning microwave beam, even the wavelengths of laser source are fixed and un-tunable. The true-time-delay system using proposed tunable chirped fiber grating delay element and sampled grating based laser source is constructed and demonstrated experimentally.     

多波长混沌掺铒光纤环形激光器实验研究

利用掺铒光纤环形激光器(EDFRL),基于光纤的非线性克尔效应,实验实现了多波长混沌激光输出。实验研究了EDFRL在时序上通过倍周期进入混沌的路径,并进行了理论分析,理论研究与实验结果一致。实验结果表明,随着抽运功率的增加,其光谱的输出呈现多波长,激光器最多可输出5个不同波长的混沌激光。采用光纤光栅进行滤波后,各个波长的输出均呈现混沌状态。     

Single-mode fiber laser based on core-cladding mode conversion

A single-mode fiber laser based on an intracavity core-cladding mode conversion is demonstrated. The fiber laser consists of an Er-doped active fiber and two fiber Bragg gratings. One Bragg grating is a core-cladding mode converter, and the other Bragg grating is a narrowband high reflector that selects the lasing wavelength. Coupling a single core mode and a single cladding mode by the grating mode converter, the laser operates as a hybrid single-mode laser. This approach for designing a laser cavity provides a much larger mode area than conventional large-mode-area step-index fibers.     

Microwave generation using an all polarization-maintaining linear cavity dual-wavelength fiber laser with tunable wavelength spacing

A stable dual-wavelength erbium-doped fiber laser with a linear cavity is formed by a polarization-maintaining uniform fiber Bragg grating (PM-FBG) and a polarization-maintaining linearly chirped fiber Bragg grating (PM-LCFBG), both of which were fabricated on a high-birefringence (Hi-Bi) fiber. Experimental results show stable dual-wavelength lasing operation with a wavelength separation of ∼0.22 nm, which can be tuned down to as small as 0.05 nm and a large optical signal-to-noise ratio (OSNR) of over 40 dB under room-temperature. Microwave signal at frequency of 9.41, 18.03 and 27.46 GHz is achieved by heterodyned the output lasing wavelengths on a photodetector.     

室温下稳定的多波长掺铒光纤激光器的研究

通过在线形谐振腔中引入一段缠绕在压电陶瓷上的单模光纤作为正弦相位调制器,使得激射波长的损耗不固定,抑制由于掺铒光纤的均匀展宽效应引起的模式竞争,从而避免了在室温下不稳定的单波长激射,实现了多波长掺铒光纤激光器的稳定输出。为了获得平坦的多波长输出,在谐振腔里使用了一个损耗峰位于1530nm处的长周期光纤光栅,以获得较为平坦的增益谱。通过两个3dB耦合器制成的反射型梳状滤波器的滤波作用,实验中观察到稳定的多波长激射,相邻波长间隔约为0．45nm。中心9个波长的输出功率平坦度为10dB,边模抑制比大于25dB。     

基于半导体纳米线和金属脊的混合表面等离子体波导模式特性分析

波长可开关光纤激光器可以选择多波长光纤激光器中的一个或多个波长输出,支持光网络中多个波长的动态分配,适应现代光纤通信系统信道数越来越多的波分复用和密集波分复用的发展方向.本文提出并实现了一种自激发多波长可开关掺铒光纤激光器.该激光器通过一个980 nm泵浦进行抽运,使用掺铒光纤作为增益介质,产生1 550 nm光谱,并通过一个环形结构返回,从而实现自激发的过程,降低了实验成本.实验使用一个含有两段保偏光纤的Sagnac环作为滤波器.通过调整Sagnac环形滤波器内偏振控制器的角度,改变Sagnac环形滤波器的腔内增益,可以让光纤光栅反射出来的波长选择性通过,从而实现波长的开关功能.实验证明,通过调整Sagnac滤波器的腔内增益而让多波长选择性通过,是一种有效的实现波长可开关功能的方法.     

Photonic generation of microwave signals using a dual-transmission-band FBG filter with controllable wavelength spacing

Two π-phase shifts are introduced in a uniform fiber Bragg grating (FBG) structure and a dual-transmission-band opens in the stopband of FBG. When incorporating this kind of FBG filter in a fiber ring cavity with a semiconductor optical amplifier (SOA) acted as gain medium, a stable dual-wavelength lasing with wavelength spacing of 0.032, 0.052 and 0.068 nm is achieved, respectively. Therefore, the laser output is heterodyned on a photodetector and desired microwave frequencies of 3.15, 6.16 and 8.08 GHz are generated. PACS 41.20.-q; 42.55.Wd; 42.81.-i     

82-channel multi-wavelength comb generation in a SOA fiber ring laser

We demonstrate a multi-wavelength semiconductor optical amplifier (SOA) fiber ring laser with a dual-pass Mach-Zehnder interferometer (MZI) filter. Two SOAs with different gain spectra provide sufficient gain and a wider gain spectrum to facilitate multi-wavelength lasing. The dual-pass MZI, configured by adding an optical isolator to the two outputs of the conventional MZI, serves as comb filter for multi-wavelength operation, and its extinction ratio can be enhanced to twofold as that of the conventional MZI in the same parameters. To investigate the influences of a dual-pass MZI filter and a conventional MZI filter on multi-wavelength operation, two different cavity configurations are presented and compared, including a single-SOA ring cavity and a double-SOA ring cavity. Stable simultaneous operation at 82 wavelengths, with a wavelength spacing of 40 GHz and a power deviation of 5 dB, and with a minimum optical signal-to-noise ratio (OSNR) of 28 dB, is observed from the double-SOA ring cavity using a dual-pass MZI filter.