In this study, a novel technique (TO-Butterfly package) for butterfly-type laser module packaging based on the coaxial type structure is proposed. By applying the low cost TO packaging technique, the cost and fabrication time can be reduced, and the yield rate can be increased. The achievement can be employed to package the novel butterfly-type laser module in the fiber optics communication. In traditional butterfly-type module package, the PWS was large while saddle clip and fiber ferrule being jointed by laser welding after the fiber ferrule and laser being aligned. Therefore, the coupling efficiency and the yield rate are low with long fabrication time. On the contrary, the TO-Butterfly package, similar to TO-Can laser module, includes upper part and lower part. The direction of the main PWS in TO-Butterfly laser module parallels to the optical axis, in which direction the components are constrained. Therefore, the PWS takes less influence on the coupling efficiency. Furthermore, the aligning process between the fiber and the laser and laser welding process is completed on Newport LW4000 workstation to build up a TO-Butterfly TOSA. After that, the TO-Butterfly TOSA is taken out of the workstation and combined with the case through solder. As a result, the fabrication time can be reduced to one-third. And the coupling efficiency and yield rate can also be improved. After several times of process modification, the coupling efficiency of the 19 TO-Butterfly TOSA modules by applying the novel packaging technology was all over 70%. The average and the highest coupling efficiency were 81.3% and 95.7%, respectively, and the standard deviation was 6.5%.

The fiber alignment shifts induced by the post-weld-shift (PWS) in laser-welded TO(Transistor outline)-Can type laser module packages is studied experimentally and numerically. The PWS induced fiber alignment shifts were quantitatively determined by four geometrical parameters: the lateral shift(r), the position angle(£\), the tilt angle(£Z), and the swing angle(£c). The measured coupling powers in laser module packages before welding, after welding, and after a compensation clearly confirmed with the measured fiber alignment shifts determined by the dominant parameters of the r and £\ that the fiber shifts due to the PWS could be realigned back closer to their original optimum position after applying a welding compensation, and hence the coupling powers loss due to the PWS could be regained. The measured coupling efficiency after laser welding was from 68% to 95%, and the overall coupling efficiency after the PWS compensation was from 77% to 97%. The increased coupling efficiency after this PWS compensation was from 2% to16%. A coupled thermal-elasto-plasticity model of finite-element method (FEM) analysis was performed to evaluate the effects of PWS on fiber alignment shifts in laser module packages. The measured fiber alignment shifts determined by the dominant parameters of the r and £\ were in good agreement with the numerical calculation of the FEM analysis. In this study, the combination of the experimental and numerical results have significantly provided a practical design guideline for fabricating reliable laser-welded TO-Can type laser module packages with a high yield and high performance for use in low-cost lightwave transmission systems. A novel measurement and compensation technique employing a high-magnification camera with image capturing system (HMCICS) to probe the post-weld-shift (PWS) induced fiber alignment shifts in high-performance butterfly-type laser module packages is investigated. The results show that the direction and magnitude of the fiber alignment shifts induced by the PWS in laser-welded butterfly-type laser module packaging can be quantitatively determined and then compensated. The measured coupling powers in laser module packages after welding and compensation clearly confirmed the measured fiber alignment shifts determined by the translational and rotational parameters that the fiber shifts due to the PWS could be realigned back closer to their original optimum position after applying a welding compensation, and hence the coupling powers loss due to the PWS could be regained. The measured coupling efficiency after laser welding was from 63% to 79%, and the overall coupling efficiency after the PWS compensation was from 69% to 89%. The increased coupling efficiency after this PWS compensation was from 3% to 10%. In comparison with previous studies of the PWS compensation by a qualitatively estimated technique in butterfly-type laser module packages, this novel HMCICS technique has significantly provided an important tool for quantitative measurement and compensation to the effect of the PWS on the fiber alignment shifts in laser module packages. Therefore, the reliable butterfly-type laser modules with a high yield and a high performance used in lightwave transmission systems can be developed and fabricated.

In this study, the capacitance displacement system (CDS) is employed to measure the post-weld-shift (PWS) induced by laser welding in butterfly type laser module package. The advantage of CDS is able to simultaneously and immediately measure the direction and the magnitude of PWS. Furthermore, with the aid of notch clip, the PWS can efficiently and quantitatively be compensated by laser hammering technique to regain the coupling power. Reduction of the PWS is an important issue in developing low-cost and high-performance laser modules. The package yield of laser modules can be imp roved due to the real-time measurement and quantitative compensation. In comparison with the high-magnification camera with image capturing system (HMCICS) having 0.7£gm resolution, the capacitance sensor achieves 25.4nm and 0.1£gm in its resolution and accuracy, respectively. Besides, during the package procedure, the real-time displacement detection can be used to adjust the package parameters. As a result, the PWS is reduced that contributes to less coupling power loss. After welding, the result reveals that the PWS was measured as X=0.15£gm and Y=-4.58£gm, while the coupling power is 43.19%.

The post-weld-shift (PWS) introduced in the butterfly laser packaging is investigated in this study. The elastic-plastic-thermal coupled finite element model is employed in the stress and deformation analyses. The temperature dependent material properties are used to calculate the residual stresses and the post-weld shift distributions during the packaging process. The finite element package ¡¥MARC¡¦ is used in this study. And the commercial optical software, i.e. ¡¥Zemax¡¦ is also employed in laser power coupling efficiency simulation. The variations of laser welding sequence, Nd-YAG pulse laser power, and initial ferrule¡¦s alignment position on PWS for butterfly laser packaging are studied and discussed in this work. The results indicated adjust the sequence and pulse laser power properly can improve the PWS in butterfly packing significantly. Besides, the PWS correction technique, i.e. the ¡¥Laser Harmering¡¦, is also illustrated in this study. The simulate results showed that proper arrange the welding processes may improve the coupling efficiency over 75¢M.

Optical transceiver module plays an important role in the optical communication system. The packaging quality of the module decides the ability of the communication. Since the light signal is transferred from a laser diode to an optical fiber, the light transfer efficiency between these two components becomes a very important work to be done. The micrometer dimension and the ultra-high performance requirement of these components lead to many problems in module packaging process. Among all the problems, the packaging of the fiber components is the most complicated. In this research, many key technologies are proposed to solve or improve the problems in the packaging of the fiber components. Thus, the performance of the module can be ensured. Two main topics of the fiber component packaging will be introduced here, the fiber-solder-ferrule (FSF) packaging and the machining of the fiber. In the packaging of the FSF, a positioning and a soldering technology are proposed to improve the packaging yield. For the positioning, a novel control strategy is constructed to shorten the positioning time and improve the positioning accuracy. Thus, the position of the fiber can be positioned at the center of the ferrule fast and precisely. The controller successfully completes the positioning command in 0.25sec with 1µm accuracy. And finally, the coupling efficiency can be hold. For the soldering of the FSF, an active soldering mechanism is developed to replace the passive manual operation. The mechanism successfully proofs the stability of the soldering and raises the yield from the 25% to 83%. In machining of the fiber, a fiber end polishing issue and a fiber inspection topic are addressed. For the fiber end polishing, an online force sensing mechanism is implemented. The force sensing mechanism can control the polished fiber tip offset within 1.5µm. So the fiber coupling efficiency can be maintained. A control strategy is designed to solve the polishing problems and reach the polishing requirement. At last, an interference-based fiber inspection method is proposed to find the splicing plane between two spliced fibers. The accuracy of the fiber cleaving in a cascaded fiber fabrication improves from 10µm to 1µm by observing the fiber splicing plane precisely. All the improvements of the above packaging technologies are proposed to raise or keep the performance of the transceiver module. So, the error between theories and experiments can be minimized. Meanwhile, a high stability and repeatability of the packaging can be achieved due to the automation of the positioning, force sensing, and inspection.

The goal of this dissertation is to provide a solution by using a low-cost and high-performance laser module package for the applications of high-speed optical communication, fiber-to-the-home (FTTH), and passive optical network (PON). A 10-Gb/s coaxial-type laser module, a 10-Gb/s bi-directional optical sub-assembly (BOSA) module, and a 4 channels x 10-Gb/s coarse wavelength division multiplexing (CWDM) laser module have been implemented for this study. The conventional TO-Can header suffers poor RF transmission characteristics without proper modification. The notch filter effect induced by the parasitic inductance of the long lead and wires is one of its major factors. The proposed coaxial laser module is fitted with a commercial TO-Can with an internal matching resistor of 18£[ to reduce the signal reflection. The comparison of small signal results between the theoretical and the experimental results shows good agreement. The proposed 10-Gb/s coaxial laser module implemented can achieve 31% mask margins with the OC-192 standard. For cost consideration, the structure of the proposed 10-Gb/s BOSA modules is adapted to the idea of the commercial low bit rate of 155-Mb/s or 1.25-Gb/s BOSA modules. The proposed BOSA modules show a clear opening eye diagrams at both their transmitter and receiver side. The power penalty with a 10-km SMF transmission is 0.5dB and the crosstalk penalty is 0.9dB. According to the experimental results, we have demonstrated successfully the high-performance and the low-cost of 10-Gb/s BOSA modules and verified the feasibility of the bi-directional architecture for use in the future¡¦s high-speed FTTH or PON network applications. The 4 channel x 10-Gb/s laser modules adapted the existing low-cost TO-Can laser and the CWDM techniques provide one of the solutions for the 40-Gb/s optical communication application. The proposed optical module operating at 10-Gb/s per channel can exceed a rate of over 30 km transmission at the bit-error-rate (BER) of 10-9, with an average system power penalty of 12 dB. The proposed high-performance 40-Gb/s CWDM module shows the low-cost possibility that ensures the application of WDM-passive optical network (WDM-PON) fiber-to-the-home (FTTH) systems.

A cost-effective 25 Gb/s directly-modulated transmitter optical sub-assembly (TOSA) packaging solutions by transistor outline (TO)-Can materials and processes were proposed and demonstrated. The purpose of this dissertation is to develop a high bandwidth TO-Can header for high-speed laser module, to verify a method, to propose a three-version of 25 Gb/s TO-Can laser module packaging, and to analyze in the frequency-domain and time-domain, and to experimentally demonstrate a 25 Gb/s TOSA. Usually, the transmission bandwidth of a conventional TO-Can laser module is limited below 10 GHz. To overcome this limitation and figure out the solution, firstly, the geometric structure of a conventional TO-56 header was analyzed by using transmission line models and electrical characteristics of the TO-56 header through a three-dimensional electromagnetism full-wave simulation software. The simulated results were in good agreement with the measured results and verify the applicability. Furthermore, we found that the 3-dB bandwidth of a conventional TO-56 header was limited at 16.7GHz. In this study, the first version of TO-Can header V1 was proposed to overcome the problem of the discontinuous impedance. By applying the TO-Can header V1, a TO-Can laser module package was proposed. The electrical characteristics parameters of the TO-Can header V1 were extracted and combined with small-signal equivalent circuit models of laser diode to simulate the electrical characteristics of the entire TO-Can laser module by the circuit simulation tool. Since bent inside feed-leads and two-step coaxial feed-through holes of the TO-Can header V1 were difficult to achieve in our laboratory equipments, the second version of TO-Can header V2 was proposed and verified experimentally. A 25 Gb/s TO-Can laser module with a matching resistor by adopting the TO-Can header V2 was proposed. The simulated results of this solution by considering with bonding-wires showed that the transmission bandwidth and eye diagram could achieve requirements of 25 Gb/s transmissions. Finally, the third version of 25 Gb/s TO-Can laser module adopted the TO-Can header V2 and an AlN submount of L-shaped microstrip line was proposed, fabricated, and measured. A DFB LD chip with a 3-dB bandwidth of 21.2 GHz was modeled and used in the simulation and the fabrication. Due to the parasitic effect induced by bonding-wires and die-bonding structure, the variation of high frequency performance of the laser module was simulated comprehensively. By referring to the proposed structure, a TOSA was fabricated by a conventional TO-Can and TOSA fabrication equipments and processes. The measured 3-dB bandwidth of the TOSA was 18.7 GHz. A clear eye diagrams of 25 Gb/s and BER testing for BTB and SMF transmission were obtained. This cost-effective solution of the TOSA is compatible with existing automatic TO-Can process lines and can be fabricated massively. Therefore, the results of this study of proposed TOSA can be applied in the next generation networks of 100GBASE-LR4, OTU4, and 32GFC. The presented simulation and verified technique may provide sufficient estimation and step-by-step analysis to assist the high-speed and high-density optical communication applications and various product developments in the future.

Ljusbommar/ljusridåer är ett vanligt säkerhetsskydd på dagens industrier, där arbete görs vid rörliga delar.  Det ställs höga säkerhetskrav på ljusbommar/ljusridåer. När ett skydd bryts behöver det återställas och detta görs vanligtvis med en tryckknapp. Detta system medför ett hinder i situationer där truckar används, eftersom att arbetaren behöver kliva ur trucken för att göra återställning av skyddet. Ett trådlöst system av återställningen är lösningen på problemet, men det ställs krav på ett sådant system. Ett öppet lasersystem har valts att undersökas om det skulle kunna uppfylla de krav som ställs. För att testa om ett öppet lasersystem skulle kunna användas togs en prototyp fram. Prototypen bestod av en lasermodul som sändare och en solcell som mottagare. Systemet styrdes av två stycken mikrokontrollers som kommunicerade via UART. Prototypen testades för hur stabilt systemet var mot ljusstörningar och inom vilket område det var begränsat. Det visade sig att den prototyp som tagits fram inte fungerade när störningsljus med frekvenser i sig belyste mottagaren. Prototypens områdesbegränsning visade sig var alldeles för stor. Slutsatsen av undersökningen var att det är teoretiskt möjligt att byta ut knappen mot ett öppet lasersystem, dock inte med den prototyp som togs fram. Det behövs istället en prototyp som måste bearbetas mer för att kunna uppfylla de krav som skulle ställas för trådlösåterställning av ljusbommar/ljusridåer. / Light beams / light curtains are a common safety guard on today's industries, where work is done on moving parts. High safety requirements are imposed on light beams / light curtains. When a protection is broken, it needs to be reset and this is usually done with a pushbutton. This system in which truckers are used, a problem arises, because the worker needs to get out of the truck to repair the guard. A wireless recovery system is the solution to the problem, but it needs to meet high standards. An open laser system has been chosen to be investigated if it could meet the requirements. To test if an open laser system could be used, a prototype was taken. The prototype consists of a laser module as a transmitter and a solar cell as a receiver. The system is controlled by two microcontrollers communicating via UART. The prototype was tested for how stable the system was and in which area it was limited. It turned out that the prototype produced did not work when the interference light with frequencies in itself illuminated the receiver. The prototype area restriction proved to be too wide in the area. The conclusion of the survey was that it is theoretically possible to replace the button with an open laser system. However, not with the prototype that was presented, but with a prototype that has to be processed more to meet the requirements for wireless reset of light bombs / light curtains.