Optoelectronic multichip module integration for chip level opticalinterconnects

We have integrated an 850-nm vertical-cavity surface-emitting laser (VCSEL), its driver, and a diffractive lenslet array onto a single substrate to produce an integrated optoelectronic multichip module for signal fan-out and distribution. The diffractive element performs optical fan-out of the output beam from the VCSEL into an array of focused spots at a plane 1, 416 μm from the surface of the VCSEL. This corresponds to 160 μm from the surface of the diffractive lens. System design, fabrication, integration, and experimental characterization is presented     

A novel one step integration of edge-emitting laser diode withmicro-elliptical lens using focused ion beam direct deposition

An edge-emitting laser diode (LD) integrated with a microlens on its emitting surface for the purpose of collimating and fiber coupling is introduced in detail in this paper. A micro-elliptical lens is adopted for the integration in terms of divergence angle in both parallel and transverse directions. The lens with dimensions of 50 μm×30 μm×4 μm is microfabricated on the emitting surface of the laser diode with operating wavelength of 635 nm directly by focused ion beam (FIB) deposition function. The SiO₂ deposition is realized by programming of the FIB machine. It is shown by test results that the focused spot size in the parallel and transverse propagation directions are 7.9 and 9.1 μm (at site of 1/e²), respectively, and the coupling efficiency of the compact and miniaturized system can reach as high as 71%. Measured far-field angles (full angle) with the microlens in both parallel and transverse directions are 2.2° and 1.2°, respectively. Compared with the original divergence angles of 31° and 14° without the micro-elliptical lens, they were greatly reduced by this method     

Collimating diode laser beams from a large-area VCSEL-array usingmicrolens array

In this letter, we demonstrate the fabrication and bonding of a 1 cm×1 cm monolithic two dimensional (2D) vertical-cavity surface-emitting laser (VCSEL) array. We coupled the array to a matched microlens array to individually collimate light from each laser. We found the beam divergence of the collimated array to be 1.6° (1/e2) for the entire array. Using a 1-cm diameter F2 lens, we were able to focus the collimated beams to a spot of 400 μm in diameter and to couple more than 75% of the array power into a 1-mm core fiber. Our results show that it is possible to uniformly bond large area VCSEL arrays to heat sinks, and to collimate light from each element into parallel beams using a single 2-D microlens array. Our results also show that the brightness of the focused beam can be further increased with a lens to near 10⁵-W/cm² Steradian, a level that is useful for many high-power applications     

OC-48 capable InGaAsN vertical cavity lasers

A selectively oxidised InGaAsN/GaAs three quantum well vertical cavity laser (VCSEL) demonstrated continuous wave (CW) lasing with a single-mode output power of 0.749 mW at 1266 nm. This is the first reported InGaAsN VCSEL capable of meeting the power and wavelength requirements for both OC-48 SR and OC-48 IR-1 compliant links. The VCSEL uses two low absorption n-type GaAs/AlGaAs distributed Brag reflectors and a tunnel junction to achieve current injection into the active region. A multimode version of the VCSEL had a output power of 1.43 mW at 1.26 μm. CW lasing continued up to temperatures as high as 107°C. The VCSEL material was grown by solid source molecular beam epitaxy with an RF nitrogen plasma source     

Monolithic integration of vertical-cavity surface-emitting laserand diffractive optical element for advanced beam shaping

We have demonstrated a vertical-cavity surface-emitting laser (VCSEL) with a monolithically integrated diffractive optical element (DOE) for advanced beam shaping. The DOE is a two-level surface relief, etched into the GaAs substrate beneath a bottom-emitting VCSEL. The combination generates a 4×4 array of focused spots 10 mm from the substrate with spot sizes down to less than 400 μm, almost at the diffraction limit. Diffraction efficiencies of 29% and uniformity errors of 14% were measured     

应用于VCSEL的宽角度光束控制非周期性高对比度光栅阵列

设计了特定周期和占空比的非周期性高对比度光栅来实现光束的波前相位控制,进而实现对光束的多角度控制.在研究中,采用有限时域差分法模拟了特殊排列的非周期高对比度光栅,并获得了-10.644°,-21.176°,-28.307°,10.644°,21.447°和28.418°的光束控制角度.基于这种多角度控制的高对比度光栅阵列,提出了一种具有多角度光束控制的VCSEL光源,这种尺寸极小的宽角发射VCSEL光源系统能使激光雷达系统的结构紧凑化和微型化.     

基于TIR结构LED准直透镜的设计与实现

介绍了一种LED自由曲面准直透镜的设计方法,并运用该方法设计了一款基于全内反射,结构的准直透镜。对初始结构不断进行逼近,最终得到准直透镜的模型。透镜外径为35 mm,总高为21.5 mm。透镜匹配Cree公司XPE光源进行计算机模拟,效率高达84.8%,K值高达125.8 cd/lm。模拟应用于35 W的探照灯时,在100 m远处形成一个直径为8 m的圆形光斑,光斑中心照度高达60 lux。透镜实际样品被制作出后,经过测试,实际透镜的光束角为3.2°。此款透镜被用于实际探照灯灯具中。     

Transverse mode selection in large-area oxide-confinedvertical-cavity surface-emitting lasers using a shallow surface relief

Transverse mode selection has been introduced in a large area oxide-confined vertical-cavity surface-emitting laser (VCSEL) by etching a shallow (only 40-nm deep) surface relief. The circular relief pattern, intended for fundamental mode selection, selects low order modes, resulting in significantly reduced beam divergence (from 48° to 13° and less over the entire drive current range) and improved spectral purity (width of emission spectrum reduced from 5 to less than 0.3 nm) compared to VCSEL's without surface relief. A maximum output power of 10 mW was measured     

入射光波波长对菲涅耳透镜衍射效率的影响

使用离子束刻蚀法成功制作高衍射效率 16阶菲涅耳透镜。菲涅耳透镜的衍射效率是评价菲涅耳透镜质量的一个重要指标。对于宽带光学系统 ,除设计、制作误差外 ,入射光波波长对菲涅耳透镜的衍射效率也有影响。针对宽带折衍混合光学系统 ,分析不同入射光波波长对菲涅耳透镜衍射效率的影响。使用四种不同光源 ,对菲涅耳透镜的衍射效率进行测试。指出在短波方向 ,衍射效率下降较多 ;在长波方向 ,衍射效率下降较少     

薄膜衍射消热差红外光学系统设计

设计了一种薄膜衍射消热差红外光学系统.此光学系统口径为200 mm,焦距为200 mm,相对孔径为1,全视场角为3°,工作波段为10.7～10.9mm.该系统采用薄膜衍射镜作为主镜,厚度为微米量级,具有口径大、重量轻的优点,解决了现有红外光学系统重量和口径无法调和的矛盾.利用含有衍射面的折衍混合透镜进行校正主镜带来的强...     

Prospects of highly efficient AlGaInP based surface emitting typering-LED for 50 and 156 Mb/s POF data link systems

The detail design and performance of the surface emitting type visible light emitting diode (LED) is described for using in the plastic optical fiber (POF)-based data links. The diode showed brightness as high as 3.5 mW@100 mA (dc) and also exhibited the beam divergence angle as low as 10° with using of well designed plastic lens. The using of LED with plastic lens helps to attain also the coupling efficiency over 70% with POF. The temperature rise of the ring LED under operation is also estimated to be 9 and 6°C less than the conventional diode at 50 and 35 mA bias currents, respectively. Transmission experiments reveal that the diode is suitable for 50 and 156 Mb/s 100 m POF-based data links     

底发射VCSEL片上点阵结构光投影装置设计

为解决现有点阵结构光投影装置中准直透镜会导致较强的零级衍射而造成投影点阵光强分布不均匀的问题,提出了一种基于底发射垂直腔面发射激光器的片上点阵光投影装置结构,并给出了衍射光学元件设计思路。首先对目标光场进行光强调整和坐标变换,在无准直透镜情况下利用基于瑞利-索末菲衍射积分的Gerchberg-Saxton改进算法获得片上衍射光学元件的相位分布,并最终对该点阵投影装置的投影效果进行评估。结果表明:在衍射光学元件设计过程中采用高斯光束作为光源时,该结构能更好地抑制零级衍射,获得光强分布更加均匀的投影点阵。此外,该结构不仅可省去透镜的安装,减小投影装置尺寸,还可通过流片工艺实现光源和衍射光学元件一体化集成。     

Phase-shifterless beam-steering micro-slotline antenna

A novel beam-steering leaky-wave antenna that uses reactive loading capacitors along the leaky line is presented. The reactive loading varies the phase constant of the leaky line, altering the direction of the main beam. A prototype was constructed and tested, demonstrating that a beam scanning angle of 23° is obtained by periodically loading the 0.06527 pF capacitors along the leaky line at 4 GHz. An electronic beam-steering antenna of scanning angle 13° was established by replacing the metal-insulator-metal (MIM) capacitors with varactors     

Beam-switchable scanning leaky-wave antenna

A beam-switchable scanning leaky-wave antenna (LWA) has been developed. This LWA with a two-terminal feeding microstrip line structure is integrated with a single port double throw (SPDT) switch as a control circuit. In dual-beam mode, the scanning angle is steered over a range of 36-64° for the right-hand beam and 144-116° for the left-hand beam. In one-beam mode, the scanning angle is measured over 20° for the right-hand beam. The measured result shows that we can change from the one-beam mode to the dual-beam mode electronically by controlling the on/off status of an SPDT switch, in contrast to the case for traditional leaky-wave antennas     

Design of integrated microlens for collimation of the vertical-cavity surface emitting laser array

A method based on the theory of transfer matrix to design the integrated microlens for the collimation of vertical-cavity surface emitting laser (VCSEL) array is presented. The integrated microlenses fabricated on the substrate directly and on a certain polymer material which is on the substrate are considered. The relationships between the radius of curvature, beam waist and the divergence angle after collimation are obtained with the help of ZEMAX. The results show that the devices with the divergence angle of 15° (1/e ²) and beam waist of 2 μm can be improved to those with the divergence angle lower than 1°, and the devices with beam waist of 10 μm can be improved to those with the divergence angle lower than 3°, which is a good reference for manufacturing high-power devices with small divergence angle. The conclusions including increasing the thicknesses of both the substrate and polymer material and reducing the diameter of oxidized layer are drawn, which will be an important guidance for experiment research.     

4×10Gbit/s并行光模块串扰优化设计

为了对4×10Gbit/s并行光模块光串扰进行优化,采用了ABCD传输矩阵法,结合光纤耦合约束条件以及准直透镜、自聚焦透镜和光纤端面球透镜的理论,设计出两套优化方案。研究了垂直腔面发射激光器光束特性,利用MATLAB进行理论分析,模拟得出光斑半径与发散角的关系,并分析了串扰情况。在ZEMAX非序列模式下完成了光路建模,优化结构中透镜参量以及光纤端面设计,进行了理论分析和实验验证,取得了优化后耦合光斑半径与耦合效率。结果表明,间接耦合优化结构中,到达光纤端面的光斑为53.72μm,耦合效率达到72.59%;而直接耦合优化结构中,到达光纤端面的光斑为3.695μm,耦合效率高达到76.11%,有效地解决了并行光模块之间的光串扰问题。这一结果对光网络信号传输质量优化方面是有帮助的。     

Dual-polarized slot-coupled patch antennas on Duroid with teflonlenses for 76.5-GHz automotive radar systems

A dual-polarized 76.5-GHz microstrip patch and teflon lens antenna system was designed, constructed, and tested. A receiver (RX) array of three dual-polarized microstrip patches was coupled through a 10-cm-diameter lens to produce radiation patterns with 3° beamwidths and beam crossovers of -3 dB. The transmitter (TX) consisted of a single dual-polarized microstrip patch coupled through a 2.5-cm-diameter lens to produce a 10° beamwidth. Slot-coupled patches were used to isolate the microstrip feed circuit from the radiating elements. The antennas and feeds were fabricated on commercially available 5880 Duriod substrates. Cross-polarization levels were less than -20 dB and were typically less than -30 dB over the entire beam at the design frequency. First sidelobe levels were no greater than -15 dB and were typically closer to -20 dB. Stepped and unstepped versions of the 10-cm-diameter receive lens were designed and fabricated. Antenna system sidelobes levels were lower with the stepped lens while the cross-polarization levels were comparable     

波前分割DOE阵列半导体激光器光束的品字形整形

半导体激光器（LD）输出光束受工作电流、个体差异的影响,发散角、输出光强出现波动。常规衍射光学元件（DOE）的激光光束整形设计只针对特定的输入输出光场,使用宽容度比较小。文中在LD 的整形中利用DOE 阵列化的处理,输入光场被分割成许多小单元,不同强度的光重新在成像平面内预定的区域内叠加,实现对光束的整形。用均匀平面波设计阵列DOE 每个单元,把高斯分布的球面波整形成品字形光强分布,衍射效率为90.53%,均匀性大约为96%;发散角在快、慢轴方向上2~16的范围内变化,均匀性为95.8%以上、衍射效率为90%以上;在离焦量16 m 内,光束质量变化不大。阵列DOE 提高了LD 光束整形系统的稳定性。     

Tunable external-cavity semiconductor laser using monolithicallyintegrated tapered amplifier and grating coupler for collimation

A novel lensless tunable external-cavity laser using monolithically integrated tapered amplifier, grating coupler (GC) and an external half mirror is proposed and demonstrated. It can be fabricated by a simple process and emits a collimated output beam. By making use of wavelength dispersion of the GC, the lasing wavelength can be angle tuned. Wavelength tuning over a wide range of 21.5 nm by 4.5° device rotation and an 84-mW output power were achieved under continuous-wave operation. A well-collimated output beam with a divergence angle as small as 0.3° was maintained over the entire tuning range     

基于红外波段的大视场谐衍射透镜设计

针对目前光学设计中,通过增加光学元件数量、限制视场角等方法来平衡像差,导致光学系统较复杂的问题,提出了一种基于红外波段的大视场谐衍射透镜设计方法。使用光学设计软件Zemax进行光学设计,使用DLL编写了一种可以自定义的表面面型,使用这种表面进行分区优化,并结合标量衍射理论进行了成像效果分析。结果显示,所设计的谐衍射透镜具有21°的视场角,截止频率(以0.1作为对比度极限)为11.4 lp/mm,并通过实验验证了该透镜的大视场单透镜成像的可行性。