波长可调谐激光器开发现状及应用市场前景

波长可调谐激光器技术特点 波长可调谐激光器可任意控制信道波长,方便准确地控制频道间隔。可调谐激光器主要由具有有源增益区和谐振腔的激光器、改变和选择波长的可调装置、稳定输出波长装置三个基本部分组成。可调谐激光器有电流调谐、温度调谐、包括微电子机械系统机械（MEMS）的机械调谐三种基本技术,一般采用其中的一种或两种技术。表1为几种可调谐激光器技术与特点比较。     

MEMS型可调外腔激光器的研究

文章提出了一种以MEMS TOF(微电子机械系统可调光滤波器)和标准具作为波长选择元件,LC(液晶)作为相位补偿元件,平面反射镜提供光反馈的可调外腔半导体激光器结构。实际研制了该结构的激光器样品,实验测得该激光器的输出功率>10dBm,边模抑制比>50dB,可调谐范围达到7nm,线宽约为200kHz。     

可调谐40nm的电泵浦1．5μm MEMS VCSEL

据《Photonics Spectra》2004年第12期报导，德国的科学家已共同合作研究出目前最宽调谐范围(达40nm)的垂直腔表面发射激光器(VCSEL)，其单模激射波长为1553—1595nm。该激光器由两个芯片组成，一个为VCSEL放大器，另一个为微电子机械系统(MEMS)反射镜膜片。反射镜膜片可用作输出耦合器，并且在该半导体的底部组合了金反射镜／介电分布布喇格反射器作为谐振器。制作时，分别生长由反射镜膜片及其GaAs衬底组成的芯片，并倒置在VCSEL增益芯片上。     

基于受激布里渊散射的可调谐多波长激光器

可调谐多波长布里渊掺铒光纤激光器将光纤中的SBS非线性放大同掺铒光纤的线性放大相结合得到室温稳定的多波长输出,具有波长间隔一致、线宽窄、功率谱相对平坦等优点。设计了一种基于光纤布拉格(FBG)反射的线性可调谐多波长布里渊掺铒光纤激光器。该线性腔激光器的一端利用光纤布拉格光栅作为反射镜,有效抑制了腔内自激模的影响,增加激光器输出波长数。布里渊泵浦信号进入布里渊增益介质之前经过掺铒光纤放大器的两次放大,降低了布里渊增益的阈值。该多波长激光器实现了1 530～1 560 nm之间30 nm可调谐范围的输出。在布里渊泵浦信号功率2 mW,980 nm泵源抽运功率60 mW情况下,1 540～1 554 nm范围内,获得了波长间隔0.088 nm的16个波长的输出。     

F心激光器

美国纽约Burleigh仪表公司报告了一台连续可调谐的红外激光器,它以F心晶体的激射作用为基础进行工作。这种新型激光器,可以预期在诸如化学反应动力学、饱和吸收研究、光声光谱学和激光同位素分离等领域得到应用。 F心激光器使用三种不同的晶体:KCl:Li,KCl:Na和RbCl.Li,目前可以提供从2.2到3.1微米波长的可调谐范围。它用一可调整盒互换晶体,不需要重新对准激光腔或改变反射镜的位置。F心激光器需要一台波长在500-800毫微米区域运转的泵浦激光器。虽然通过全波长范围的调谐必需1瓦,     

光纤通信中的MEMS外腔可调谐激光器技术

文中对目前的基于MEMS技术的外腔激光器进行了深入探讨,并对典型的MEMS外腔激光器从结构进行了分类探讨,并进行了详细说明。另外,从激光器理论角度对MEMS结构的激光器的参数和影响因素进行了分析。最后,对当前的研究现状进行了简要总结,并对基于MEMS技术的外腔可调谐激光器技术进行了展望和预测。     

用温度控制可调谐激光器波长稳定的方法

介绍了可调谐半导体激光器在光通信领域的应用及其工作原理.重点讨论了SSG-DBR可调谐激光器的结构、工作原理,以及波长稳定控制方法.提出了一种新的基于温度反馈的波长稳定控制方法,使可调谐激光器的输出在20℃～70℃范围内的波长漂移小于1nm,边模抑制比优于5dB.该方法简单、可靠,将会对可调谐激光器在全光网络中的应用起到一定的推动作用.     

内腔亚波长光栅MEMS VCSELs的波长调谐范围

微机电系统(MEMS)垂直腔面发射激光器(VCSELs)是一种特殊光源,具有低功耗、高调制速率、宽波长调谐范围、易耦合等优点,被广泛应用于激光通信领域。为提升激光器工作性能,如扩大波长调谐范围、提高偏振对比度等,需要优化内腔亚波长光栅结构参数来改善腔内光场分布以及偏振输出模式。基于等效介质理论(EMT),并结合薄膜理论设计了针对调谐范围中心波长为850nm、GaAs材料的亚波长光栅的较优周期、占空比、脊高的取值。分析了横电(TE)、横磁(TM)光,占空比与脊高对光栅透射率的影响。另外,通过系统模拟,对比了未刻蚀光栅、光栅未优化及光栅优化后的激光器波长调谐范围,结果表明:针对特定波长调谐范围及光栅材料,通过优化光栅参数可实现光栅对TE或TM光的增透,增强半导体腔和空气隙之间光场的耦合,进而扩大激光器的波长调谐范围。     

可调谐激光器技术及其在DWDM系统的应用

大容量、长距离DWDM传输系统及动态波长交换DWDM光网络对保护方式、波长分配、波长备份成本的要求,使可调谐激光器变得十分重要。讨论了常用可调谐激光器的技术原理和水平,概要说明了可调谐激光器的市场前景,介绍了可调谐激光器在DWDM系统中的部分应用。     

连续波掺钛蓝宝石激光器的全波段可调谐振荡

连续波掺钛蓝宝石激光器的全波段可调谐振荡日本昭和光子公司开发连续波掺钛蓝宝石的全波长可变区（６６３～１０９０ｕｒｎ）的宽带、低损耗反射镜，并与理化学研究所光动力学研究中心共同研究，仅用一组这种反射镜在世界首次实现掺钛蓝宝石激光器的全波段振荡。它打破了...     

Continuous wavelength tuning in micromachined Littrow external-cavity lasers

This work presents the theory and experiment of the wavelength continuously tunable lasers, whose external cavities are constructed by the microelectromechanical systems (MEMS) technology. The theoretical study reexamines the wavelength tuning theory and adapts it to the MEMS tunable lasers under special concerns of the system properties such as short cavity length and prealigned component position. It is shown that in the MEMS Littrow lasers a mode-hop-free wavelength tuning requires a moving pivot, or in other words, a fixed pivot has only limited tuning range. In addition, it is also found that the wavelength dependence of the gain medium refractive index significantly affects the wavelength tuning range. Based on the theoretical study, a tuning structure is fabricated by the deep reactive ion etching (DRIE) on a silicon-on-insulator (SOI) wafer, and hybridly integrated with a gain chip and an optical fiber. The laser has dimensions as small as 2.0 mm/spl times/1.5 mm/spl times/0.6 mm, and can be tuned continuously over 30.3 nm at a resolution of 0.03 nm/V/sup 2/. As a comparison, another MEMS tunable laser designed according to the conventional theory has only a tuning range of 5.9 nm.     

Photonic MEMS tunable laser sources

This article covers laser configurations, design and experiments of photonic microelectromechanical systems (MEMS) tunable laser sources. Three different types of MEMS tunable lasers such as MEMS coupled-cavity lasers, injection-locked laser systems and dual-wavelength tunable lasers are demonstrated as examples of natural synergy of MEMS with photonics. The expansion and penetration of the MEMS technology to silicon optoelectronic creates on-chip optical systems at an unprecedented scale of integration. While producing better integration with robustness and compactness, MEMS improves the functionalities and specifications of laser chips. Additionally, MEMS tunable lasers are featured with small size, high tuning speed, wide tuning range and CMOS compatible integration, which broaden their applications to many fields.     

Optical MEMS for Lightwave Communication

The intensive investment in optical microelectromechanical systems (MEMS) in the last decade has led to many successful components that satisfy the requirements of lightwave communication networks. In this paper, we review the current state of the art of MEMS devices and subsystems for lightwave communication applications. Depending on the design, these components can either be broadband (wavelength independent) or wavelength selective. Broadband devices include optical switches, crossconnects, optical attenuators, and data modulators, while wavelength-selective components encompass wavelength add/drop multiplexers, wavelength-selective switches and crossconnects, spectral equalizers, dispersion compensators, spectrometers, and tunable lasers. Integration of MEMS and planar lightwave circuits, microresonators, and photonic crystals could lead to further reduction in size and cost     

利用NOLM同时实现两个波长的波长变换

最先利用非线性光学环路镜(NOLM)成功地将2.5Gbit/s的归零码光脉冲同时变换到不同的两个波长上.最大波长变换间距为35nm.实验系统中采用增益开关分布反馈半导体激光器(GS DFB-LD)产生的超短光脉冲作为控制光,采用分布反馈半导体激光器(DFB-LD)和波长可调激光器作为信号光.首次在1.55 μm波长段利用非线性光学环路镜进行波长变换过程时观测到了反相波长变换和脉冲畸变现象.     

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.     

Tunable GaInNAs lasers with photonic crystal mirrors

We present results of tunable GaInNAs lasers with photonic crystal (PhQ mirrors, fabricated from GaAs-AlGaAs layers with a double GaInNAs quantum well emitting at IR wavelength. The devices are realized as ridge waveguide lasers with two coupled segments and a total length between 240 and 580 pm. PhC blocks with different thicknesses are used for the back and front mirror as well as for the intermediate reflector between the two segments. The lasers have threshold currents around 20 mA and output powers up to 6 mW. Tuning of the laser emission over 30 nm is achieved by a variation of the currents injected into the two segments.     

Tunable modelocked bismuth-doped soliton fibre laser

A modelocked bismuth-doped soliton fibre laser is reported. A stable passively modelocked operation in an anomalous dispersion regime is achieved using a dilute nitride (GaInNAs)-based semiconductor saturable absorber mirror and a transmission grating pair for dispersion compensation. The laser generated 0.9 ps soliton pulses with a repetition rate of 7.5 MHz and wavelength tunable from 1153? 1170 nm. These are the shortest pulses obtained so far from Bidoped fibre lasers.     

Modal Properties of Long-Wavelength Tunable MEMS-VCSELs With Curved Mirrors: Comparison of Experiment and Modeling

The effective interplay of simulation and experimental results for analysis and optimization of microelectromechanical system (MEMS)-tunable vertical-cavity surface-emitting lasers (VCSELs) operating at wavelength around 1.55 mum is presented. The VCSEL combines a MEMS with concave Al-GaAs-GaAs mirror membrane and an InP-based active cavity with tunnel junction aperture in a hybrid two-chip assembly. Using electrothermal MEMS actuation the included air-gap can be expanded and the cavity resonance can be tuned to longer wavelengths. The experimental results are compared with the theoretical results provided by VELM (VCSEL ELectroMagnetic), the efficient code based on the coupled mode model and adapted for the first time to handle curved-mirror geometries. The vectorial code is found to be able to fully reproduce the experimental results, such as device tuning range, modal frequency splitting, threshold gains and modal selectivity.     

Analysis of large-signal dynamic characteristics of 10-Gb/s tunable distributed Bragg reflector lasers integrated with electroabsorption modulator and semiconductor optical amplifier based on the time-dependent transfer matrix method

We investigate large-signal dynamic characteristics of tunable distributed Bragg reflector (DBR) lasers with different structures. Because of high chirp and complex structures of tunable DBR lasers, it is difficult to accurately analyze large signal chirp and output pulse shapes with analytical models. Therefore, we apply a numerical model based on the time-dependent transfer matrix method to tunable DBR lasers integrated with electroabsorption modulator (EAM) and semiconductor optical amplifier (SOA). Using this model, we find a suitable /spl alpha/-parameter range in the Bragg grating section (/spl alpha//sub Bragg/-parameter) that produces the tolerable wavelength chirp while maintaining a proper tuning range. To employ the tunable lasers in wavelength division multiplexed networks and improve flexibility of the networks, the tunable lasers should have high output power and low wavelength chirp. According to our simulation results, the EAM section had better be located in between SOA and DBR laser sections to obtain high output power and low wavelength chirp.     

Half-symmetric cavity tunable microelectromechanical VCSEL withsingle spatial mode

A new class of microelectromechanically tunable vertical-cavity surface-emitting lasers with a half-symmetric cavity structure is described. The cavity is realized by inducing a curvature (R~320 μm) in the top movable dielectric mirror. The microcavity forces lasing oscillations in a single fundamental spatial mode of approximately 6 μm despite the 20 μm electrical aperture of the device. The device wavelength was tunable from 863 to 833 nm under a 13-V voltage swing. The device operates in a single fundamental mode with sidemode supression ratio of >20 dB throughout the tuning range