Tunable multiwavelength fiber ring lasers using a programmable high-birefringence fiber loop mirror

We demonstrate a comb filter with digitally tunable wavelength spacing using a programmable high-birefringence (HiBi) fiber loop mirror (FLM). We then use the HiBi-FLM to implement a tunable multiwavelength semiconductor optical amplifier (SOA)-based fiber ring laser and a tunable multiwavelength all-fiber Raman ring laser. Both lasers exhibit stable room-temperature operation and have a wavelength spacing that is digitally tunable between 1.6 and 3.2 nm. With the SOA-based configuration, we obtain six wavelengths with a spacing of 3.2 nm and 11 wavelengths with a spacing of 1.6 nm; with the all-fiber Raman-based configuration, we obtain four wavelengths with a spacing of 3.2 nm and five wavelengths with a spacing of 1.6 nm.     

双波长可切换飞秒锁模光纤激光器

报道了基于非线性偏振旋转技术的双波长可切换飞秒锁模光纤激光器.通过改变泵浦功率以及偏振控制器状态,激光器在波长1533.2 nm和1557.2 nm处可实现双波长锁模,两个波长的间隔为24 nm.在这两个波长之间还可实现可切换运作,对应的3 dB带宽分别为5.53 nm和4.69 nm,脉冲宽度分别为730 fs和89...     

基于光纤拉锥及相位调制的可切换多波长掺铒光纤激光器

研究了一种全光纤可切换多波长掺铒光纤激光器。该激光器利用一段缠绕在压电陶瓷上的单模光纤作为正弦相位调制器以及基于光纤拉锥的马赫-曾德尔干涉仪作为梳状滤波器,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。实验中观察到稳定的5个波长的同时激射,相邻波长间隔为0.804 nm。信噪比大于40 dB,3 dB带宽约为0.023 nm,中心5个波长输出功率的平坦度为14 dB。同时,激光器具有灵活的波长可切换特性,通过调整驱动信号和偏振控制器的状态,实现了单波长、双波长、三波长以及更多波长的输出。该激光器可应用于大容量波分复用系统和光纤传感。     

Gain flattening of an erbium-doped fiber amplifier using ahigh-birefringence fiber loop mirror

We propose a flexible method for flattening the gain profile of an erbium-doped fiber amplifier (EDFA). The method is based on a high-birefringence fiber loop mirror (HiBi-FLM), which contains a number of high-birefringence fiber sections and polarization controllers. We show that, by setting the polarization controllers properly, the reflection spectrum of the loop mirror can be adjusted to compensate for the variations in the gain profile of the EDFA. The method is demonstrated experimentally by using a single-section HiBi-FLM and a two-section HiBi-FLM, respectively, With a two-section HiBi-FLM, we are able to flatten the gain profile of an EDFA to within ±0.9 dB over a bandwidth of 33 nm at the center wavelength of 1543 nm, under different operating conditions of the EDFA     

双波长可切换方波类噪声锁模线形光纤激光器

采用非线性偏振旋转锁模技术,在线形腔光纤激光器获得双波长可切换方波类噪声锁模。通过调节腔参数,激光器在波长1530 nm和1563 nm处分别获得可切换单波长方波类噪声锁模,最大脉冲宽度分别为12 ns和26 ns,腔内最大的脉冲能量分别可达14.7 nJ和45.6 nJ。此外激光器还可在这两波长处实现双波长类噪声锁模,锁模脉冲呈阶梯形,最大脉宽为5 ns,阶梯形脉冲的产生主要源于不同中心波长处的方波脉冲叠加。实验结果有助于进一步理解线形腔光纤激光器中方波类噪声的产生机理和特性,并为多波长高能量光源的设计提供参考。     

波长可切换窄线宽单频掺镱光纤激光器（特邀）

基于光纤环形激光器,设计出由三端口环形器、偏振控制器、未泵浦保偏掺镱光纤和光纤布拉格光栅组成的滤波器件作为高精度滤波器对谐振腔内的模式个数进行抑制,通过调谐偏振控制器,在保偏掺镱光纤内形成的梳状光谱和动态光栅,实现了窄线宽、单、双波长可切换单频掺镱光纤激光器。单波长运行时,在1064.37 nm处测得激光器输出线宽346 Hz,光信噪比大于50 dB,30 min内该激光器波长及功率的不稳定性均在0.01 nm和0.2 dB范围内。通过调节偏振控制器,单波长和双波长可以实现互相切换,双波长分别位于1064.156 nm和1065.236 nm。该技术为超窄线宽激光器的双波长输出提供了新的途径。     

基于啁啾光纤光栅的五波长掺铒光纤激光器

提出并实验验证了一种新型的基于啁啾光纤光栅的全光纤的可切换的五波长掺铒光纤激光器,该激光器采用简洁的线性腔结构,使用一段高掺铒的光纤作为增益介质,利用一个内含宽带啁啾光纤光栅的萨格纳克环作为激光器的谐振腔腔镜,担当了一个梳状滤波器的作用,另一个腔镜由一个宽带光纤反射镜担当,适当调整环中的偏振控制器,可以获得最多五波长的激光输出,并具有4种不同的激光输出模式,所有激发线均具有大于32 dB的光学信噪比,小于0.6 nm的线宽以及小于8 dB的峰值功率差异。     

Single-/dual-wavelength switchable and tunable compound-cavity erbium-doped fiber laser with super-narrow linewidth

A single-/dual-wavelength switchable and tunable erbium-doped fiber laser (EDFL) with super-narrow linewidth has been proposed and experimentally demonstrated at room temperature. The fiber laser is based on a compound cavity simply composed of a ring main cavity and a two-ring subring cavity (TR-SC). Regardless of single- or dual-wavelength operation, the EDFL could always work well in single-longitudinal-mode (SLM) state at every oscillating wavelength. In dual-wavelength operation, the spacing could be tuned from 0 nm to 4.83 nm. In single-wavelength operation, the EDFL could lase at a fixed wavelength of 1 543.65 nm or another wavelength with a tunable range of 4.83 nm. The super-narrow linewidths of 550 Hz and 600 Hz for two wavelengths are obtained. The proposed EDFL has potential applications in microwave/terahertz-wave generation and high-precision distributed fiber optical sensing.     

A nonlinear optical loop mirror-based linear cavity swit- chable multi-wavelength erbium-doped fiber laser

A nonlinear optical loop mirror (NOLM)-based linear cavity switchable multi-wavelength erbium-doped fiber (EDF) laser is proposed and experimentally demonstrated. Due to the characteristics of the intensity-dependent transmissivity, the NOLM can effectively mitigate the mode competition of the homogenous broadening gain medium, so that the multi-wavelength lasing can be achieved at room temperature. By adjusting the states of the polarization controllers (PCs), the number of the lasing wavelengths in the proposed laser can be adjusted flexibly from 11 to 13 with a wavelength spacing of 0.4 nm around the wavelength of 1 530 nm.     

Switchable-multi-wavelength fiber laser based on dual-core all-solid photonic bandgap fiber

In this paper, we propose and demonstrate a switchable multi-wavelength fiber laser based on a dual-core all-solid photonic bandgap fiber (PBGF) comb-like filter. The transmission properties of the dual-core all-solid PBGF are theoretically and experimentally investigated. Then the fiber ring laser based on the PBGF is realized and its wavelength-selective mechanisms are studied. By adjusting the polarization controller (PC), the number and location of the laser wavelength can be tunable.     

Switchable dual-wavelength erbium-doped fiber laser based on the photonic crystal fiber loop mirror and chirped fiber Bragg grating

The switchable dual-wavelength erbium-doped fiber laser(EDFL) with a two-mode photonic crystal fiber(PCF) loop mirror and a chirped fiber Bragg grating(CFBG) at room temperature is proposed and experimentally demonstrated.The two-mode PCF loop mirror is formed by inserting a piece of two-mode PCF into a Sagnac loop mirror,with the air-holes of the PCF intentionally collapsing at the splices.By adjusting the state of the polarization controller(PC) appropriately,the laser can be switched between ...     

Switchable dual-wavelength ytterbium-doped fiber laser based on a few-mode fiber grating

The authors propose and demonstrate a simple switchable dual-wavelength Ytterbium-doped fiber laser based on a few-mode fiber grating. The laser can be designed to operate in stable dual-wavelength or wavelength-switching modes, due to the polarization hole burning enhanced by the few-mode fiber grating. The lasing lines may be controlled only by a polarization controller. Stable operation is achieved at room temperature when the wavelength separation is 0.9 nm.     

采用双Sagnac环滤波器的可切换多波长光纤激光器

提出了一种基于双Sagnac环滤波器的可切换多波长掺铒光纤激光器,该滤波器由基于保偏光纤和少模光纤的Sagnac环并联构成,结构简单,利用其梳状滤波特性,实现了掺铒光纤激光器的多波长输出。采用传输矩阵法详细分析了双Sagnac环的传输特性,进一步搭建了线性腔掺铒光纤激光器,实验中通过调节偏振控制器,改变腔内偏振态,在室温下得到稳定可切换的单、双、三波长激光输出,且激光器输出波长的位置可调。研究结果表明,输出激光波长的边模抑制比大于34 dB,稳定性测量中波长漂移量小于0.05 nm,具有良好的稳定性,可应用于波分复用及全光通信系统等领域。     

基于飞秒激光直写FBG的C+L波段掺铒光纤激光器

提出并设计了一种基于飞秒激光直写制备光纤布拉格光栅阵列的C+L波段掺铒光纤激光器,实现了波长可切换的单波长及双波长激光输出。采用飞秒激光透过聚酰亚胺光纤保护层在纤芯直写的方法,分别实现周期为538、542、547 nm的光纤布拉格光栅刻写,单个光栅栅区长度3 000 m。作为选频器件的光栅阵列反射波长分别为1 555.5、1 569.6、1 583.8 nm;选用长度为3 m的C波段和10 m的L波段掺铒光纤组合作为激光器增益介质,结合泵浦源、光纤布拉格光栅偏振控制器及宽带全反镜构成线形腔结构光纤激光器。实验结果表明:激光器工作阈值为35 mW,通过调节偏振控制器能够实现1 555.4、1 569、1 583.2 nm单波长激光可切换输出,激光3 dB线宽0.05 nm,边模抑制比大于35 dB;实验中分别对单波长激光的光谱稳定性进行了测试,10 min内最大功率波动小于0.98 dB;通过调节偏振控制器可分别实现1 569、1 583.2 nm以及1 555.4、1 569 nm双波长激光同时输出,在10 min监测时间内,输出激光功率变化分别小于1.14 dB和4.48 dB。     

Studies on strain and temperature characteristics of a slanted multimode fiber Bragg grating and its application in multiwavelength fiber Raman ring laser

Detailed strain and temperature characteristics of a 2/spl deg/ slanted multimode fiber Bragg grating (MFBG) are developed theoretically and observed experimentally. Results show that the strain and temperature sensitivities are almost the same for different transmission dips of the 2/spl deg/ slanted MFBG. Utilizing two characteristics of the 2/spl deg/ slanted MFBG, namely 1) resonant wavelength intensities strongly affected by excited mode propagating before the grating and 2) uniform strain sensitivities of different resonant wavelengths, a switchable and tunable multiwavelength fiber Raman ring laser is realized. The configuration is simple and multipurpose. Results show that the laser can generate single-, dual-, three-, four-, and five-wavelength lasing by switching between each operation if a mode scrambler (MS) that is inserted in front of the slanted MFBG is adjusted; furthermore, a 4.2-nm continuous wavelength-tuning range is achieved by straining the slanted MFBG when the MS is fixed.     

Precisely and rapidly wavelength-switchable narrow-linewidth1.5-μm laser source for wavelength division multiplexing applications

We report the design and demonstration of a novel narrow-linewidth fiber laser that is switchable (at microsecond speeds) to precise predesignated wavelengths. This simple multiwavelength source, based on off-the-shelf components (fiber Bragg gratings (FBGs) and fiber Fabry-Perot filters), appears very promising for wavelength-division multiplexing     

A switchable dual-wavelength erbium-doped fiber laser based on Sagnac loop inserted with two FBGs

A novel switchable dual-wavelength erbium-doped fiber （EDF） laser is demonstrated. The wavelength selection ele- ment consists of two fiber Bragg gratings （FBGs）, a polarization controller （PC） and a 3 dB coupler forming a Sagnac loop inserted with two FBGs. We study the effect of coupling ratio on filtering performance in this paper. By adjusting PC, we can change the wavelength-dependent loss, and then using nonlinear polarization rotation effect to suppress the mode competition caused by the homogeneous broadening of EDF, we obtain single- and double-wavelength laser outputs. At room temperature, under 200 mW pump power, dual-wavelength laser is achieved, and the center wave- lengths are 1545.34 nm and 1548.20 nm, respectively. The peak power values are -13.36 dBm and -14.58 dBm, and side mode suppression ratios （SMSRs） are 41.10 dB and 39.88 dB, respectively. Within two hours, the maximum fluctuation of peak power is less than 0.7 dB, which shows that the demonstrated fiber laser is stable. Moreover, by adjusting PC, singel-wavelength laser output is obtained, the peak power is -6.27 dBm or -5.45 dBm, and SMSR is 40.03 dB or 39.96 dB at 1545.34 nm or 1548.20 nm, respectively.     

波长可切换可调谐耗散孤子锁模掺镱光纤激光器

采用非线性偏振旋转(NPR)锁模技术,在全正色散掺镱光纤激光器中研究了波长可调谐可切换耗散孤子锁模现象。由于NPR所诱导的腔内梳状滤波效应,光纤激光器在中心波长1 042.8~1 050.2 nm以及1 040.9~1 048.1 nm处实现了波长可切换运作,可切换波长间隔分别为7.4 nm和7.2 nm,光谱宽度约为5.5 nm和2.7 nm。同时在1 042.77~1 045.33 nm之间观察到波长可调谐运作,调谐范围2.7 nm。另外在光纤激光器中还获得了稳定的双波长锁模和二阶谐波锁模。该实验的研究有利于加深人们对掺镱光纤激光器中锁模动力学行为的理解,并为多功能激光光源的设计提供了借鉴。     

L波段可调谐Er/Yb共掺环形腔光纤激光器

报道了一种工作在L波段波长可调的环形腔Er／Yb共掺双包层光纤激光器。利用两段高双折射光纤和两个偏振控制器组成的环形镜作波长选择器件，通过调整环形镜中偏振控制器的状态来改变环形镜对不同波长的反射率以实现某波长的激光输出，使波长调节范围达到60nm，不同波长处激光输出功率的起伏小于0．7dB；采用较长的Er／Yb共掺双包层光纤(EYDF)作增益介质，利用6个976nm激光二极管同时抽运前段Er／Yb共掺双包层光纤所产生的放大自发辐射谱作为二次抽运源，对腔内未被抽运的一段Er／Yb共掺双包层光纤进行抽运，使增益谱移到L波段，实现了L波段可调谐激光器的稳定输出。在最大抽运功率为3594．5mW时，测得抽运入纤功率为2737．37mW，得到最大输出功率300mW，斜率效率为11％的激光输出，所形成激光光谱的3dB带宽为1．8nm，边模抑制比大于38dB。     

Multi-wavelength Raman fiber laser with 2- and 3-stage cavities in a phosphosilicate fiber

We report on the simultaneous Raman lasing of three wavelengths at 1428/1454/1495 nm in a single P-doped optical fiber, by use of the stimulated Raman scattering of both P₂O₅ and SiO₂/GeO₂. The laser is formed with fiber Bragg grating cavities and the destination laser wavelengths are obtained through respective two- and three-stage Raman cascading processes for efficient wavelength conversion. Thermally controllable power ratios between the wavelengths have been realized by temperature detuning the most efficient 2-stage resonant wavelength at 1495 nm. With a comparable power level at each wavelength, the maximum total power achieved in our multi-wavelength Raman laser is 2.87 W in a fiber length of 700 m pumped with a 20 W double clad Yb fiber laser.