Alignment for Optics & Silicon Photonics FAST MULTI-CHANNEL PHOTONIC ALIGNMENT SYSTEM 7 1 0 2 G K o. C & H b m G PI) e ( nt e m u nstr ysik I h P © e. otic n ut o h wit e g n a h o c ect t bj u S 0 1. 7 1 0 2 6/ 0 nics o ot h P n o Silic E 7 5 O R B WWW.PI.WS Silicon Photonics (SiP) The rapid advent of Silicon Photonics offers promise for bandwidth, efficiency and extensibility, and it presents many challenges for test and packaging processes. Key among these is the need to align fiber optic devices to optimize optical throughput before testing or packaging can begin. Simple economics necessitates fast throughput in this unpredictable nanoscale-accurate step. Silicon photonics devices often need alignments in multiple degrees of freedom across more than one input or output coupling, and these can interact, presenting moving targets. PROBING CHIP TEST Sometimes, getting exactly the right coupling can be tricky and time-consuming. PI can make this a quick process, ensuring Clearly, manual approaches are not scalable over the volume demands SiP devices against the wasteful packaging of pro- are enjoying. Even automated solutions can require lengthy iterative loops that kill duct that acquires damage during multiple test and packaging economics. packaging steps. Custom, embeddable configurations are welcome. PI’s alignment automation options provide exacting optimization using a deep toolkit of firmware-based algorithms. PI’s unique, fully parallel technology can optimize multiple degrees of freedom, multiple inputs and outputs across multiple channels, or even multiple devices all at once. PI hexapod-based solutions offer a freely selectable pivot point, so you can optimize by rotating about a beam waist, focal point or optical axis for further efficiencies. WAFER TEST On-wafer photonic device testing is essen- tial to ensure against faulty devices pro- ceeding through the costly packaging process. Today’s silicon photonics devices are more complex than ever, with multi- ple inputs and outputs that often inter- act, multiple channels, and alignments that must be optimized across multiple degrees of freedom in order for tests to proceed. Cascade Microtech’s pioneering CM300 photonics-enabled engineering wafer prober integrates PI’s Fast Multi-Channel Photonics Alignment systems for high throughput, wafer-safe, nano-precision optical probing of on-wafer Silicon Photonics devices. Photo courtesy Cascade Microtech div. of Formfactor, Inc. 2 WWW.PI.WS Packaging PI’s deep industrial alignment toolkit includes all you need to address your test and production needs, including the world’s most comprehensive line of photonics-focused mechanisms and controls. For example, make quick work of the multichannel optimiza- tions; perform parallel optimization of multiple elements; quickly optimize in all degrees of freedom— all key capabilities for today’s complex and tightly-packed photonic devices! This optimization can be continuous, tracking minute dimensional changes during burn-in and compensating for curing stresses and other drift processes. ARRAY DEVICE ALIGNMENT Array devices and others with angular optimization formerly required time- consuming, sequential optimizations. For example, theta-Z alignments could only be performed stepwise, with an XY optimization in between steps. This rendered the overall alignment very time-consuming. And time is money, especially today. PI addresses this through parallelism, a unique new capability. In the theta-Z example just mentioned, the lengthy loop of stepwise iterations in XY, then theta-Z, then XY, and so on, is replaced with a one-step optimization of both at the same time. Additional angular optimizations and (in the case of a waisted coupling) Z optimization can be performed at the same time too, allowing a one-step global optimization, and tracking too. The resulting, typically 1-2 order of magnitude improvement in test and packaging throughput has a profound impact on process economics. PI products come standard with a wealth of analog interfaces for connection to one or more PI optical power meters or other high-speed optical metrology instru- ments and sensors, including embedded sensors. Additional analog resources can be specified as needed. This means array devices can be optimized by aligning the two outermost elements or by balancing the coupling of multiple additional channels. Either way, alignment is as fast and accurate as you would expect from PI, the world leader in NanoAutomation®. 3 MOTION | POSITIONING Basics of PI’s Unique Fast Multi-Channel Photonic Alignment (FMPA) COMPREHENSIVE SOFTWARE STACK ENABLES EASY INTEGRATION AND USE Start with quick set-up, exploration and ease of use with PIMikroMove. Proceed to productivity with useful, open- source graphical applications examples that include scrip- tability for fast construction of test executives using virtually any language. Rapidly construct custom applications using PI libraries and samples for popular platforms including C++, C#, MATLAB, Python and LabVIEW on Windows, Linux and macOS. 100% ASCII communications ensures compatibility with legacy fab computers. Output Input Output Input Testing and packaging today’s photonic devices can be a optical path multi-degree-of-freedom challenge and a moving target. PI’s industrial-class solutions help you make it a fast, repro- optical path ducible, one-step process. y y o i x z z x o o i i y y o i ■ misaligned optical path xo zo zi xi ■ ideal optical path ■ misaligned optical path ■ ideal optical path GROUNDBREAKING BUILT-IN ROU- TINES FOR FASTEST PEAK FINDING Built-in routines enable extremely high alignment speed. The algorithms for first light, area scan, and gradient scan routines are extraordinarily fast and reliable for all kind of couplings. They offer process time of less than 1 second for aligning input and output simultaneously. PI algo- rithms even include automatic modeling of scan data to accurately localize the optimum even in fast, coarse scans. This includes the ability to rapidly localize the centroid of top-hat couplings – another PI world exclusive. 4 WWW.PI.WS Automated Alignment is the Key to High Throughput and Outstanding Quality The key component of the alignment systems is PI’s Nano- Cube®, a highly dynamic, closed-loop XYZ piezo scanner. It is so compact yet yields 100 x 100 x 100 µm travel with nanoscale repeatability and extreme speed. With a completely wear-free working principle, it makes even the most compli- cated coupling optimizations possible in typically a few hundred milliseconds. The integrated optical encoder offers the highest bandwidth and resolution for this high-dynamic application. Closed-loop operation helps ensure device safety and process repeatability. PI hexapods offer all 6 degrees of freedom, namely 3 linear and 3 rotational axes, combined into parallel kinematics. A further advantage of the hexapod is the user-definable pivot point that enables rotation directly around the fiber tip and if required, also allows any other point of rotation. Either stacked linear axes or hexapods can be used for positioning or scanning larger areas. In the case of stacked systems, a lot of value was placed on robustness and stiff- ness. All linear axes are equipped with position sensors and are connected to each other by very stiff brackets. High- quality components and a solid design guarantee reliability and a long lifetime. 5 MOTION | POSITIONING First Light Scan In order to determine the global maximum of a signal, it is necessary to make an intensity signal available to the controller that can be optimized. The built-in firmware algorithms provide all convenient and fast searching for ‘first light’. To ensure extremely fast success for first light searching, it is possible to combine several area scan routines for this scan, which can be performed simultaneously. This can be performed quickly and reliably even for double- sided tasks, where both sides need to be coupled at the same time; the firmware-based algorithms run fully automatically and simultaneously until the predefined threshold value has been reached or the entire area has been scanned. All axes, irrespective of whether they are coarse or fine axes, can be used and configured according to their dynamics. For example, the transmitter side can perform highly dynamic area scans, during which, the receiver side moves slowly but continuously. Therefore, the entire transmitter side is scanned for each and every position on the receiver side. It is also possible to set whether scanning stops as soon as the defined threshold value has been reached or whether the entire area of both sides should be examined. 6 WWW.PI.WS Area Scan Routines The FMPA system offers 3 different routines for an area scan. The spiral scan with constant angular velocity, the spiral scan with con- stant path velocity, and the sinusoidal area scan. All routines can be configured individually and therefore optimized for the respective application case. Several scan routines can also be started simul- taneously with a single command. It is possible to calculate the approximate maximum using a Gauss function or by determining the centroid. In the case of the sinusoidal scan routine the defined surface is scanned continuously without strong acceleration or deceleration phases. Surface, starting point, line distance, and success criteria can be defined by the user. In the case of the spiral scan routine, a defined area is scanned helically, whereby either a constant angle or a constant path velo- city is maintained. The advantage of spiral scanning at a constant frequency is the ability to avoid system resonance. This ensures successful scanning. The advantage of spiral scanning at a constant path velocity is the ability to reduce the scanning duration in the case of lower system dynamics. Application-specific configuration of the routine is also possible here. Gradient Search Routines Ground-breaking results can be achieved with the unique implementation of this algorithm. If the light signal is present, this gradient search makes it possible to find the signal maximum in less than 1 second even in the case of double-sided tasks. It is also possible to run several searches at the same time and therefore optimize the signal simultaneously in several degrees of freedom. The routine allows excellent „tracking“ and therefore it is ppoossssiibbllee ttoo ccoommppeennssaattee aannyy ddrriifftt eeffffeeccttss.. SSeevveerraall ppaarraammeetteerrss aarree aallssoo aavvaaiillaabbllee hheerree ffoorr ooppttiimmiizziinngg tthhee sseeaarrcchh for the respective application case. 7 MOTION | POSITIONING PIMikroMove PIMikroMove gives you the option to control axes, perform (manual) tuning as well as record data from the controller in real time, display the data graphically and also analyze the data. Furthermore, it is also possible to access all controller algorithms and parametrize them con- veniently; this also includes the fast alignment routines. A live display of the analog inputs (incl. floating chart) as well as a 3-D view of optical distribution of the scanned area is particularly interesting for alignment tasks. Of course, it is also possible to export the data (.csv). Various tools are available for realtime data analysis, triggering, configuration, and much more. PIMikroMove does not only offer the possibility of analyzing the dynamic properties of the PI axes, but can even perform an evaluation of the overall system with the help of an FFT analysis of the optical signal. PIMikroMove application for Windows provides quick access to motion & scanning across all PI products regardless of drive technology, controller type, no. of axes etc. Includes software-based scan & align routines which work with all available PI motion controllers and access to all available firmware-based fast alignment algorithms. 8 WWW.PI.WS Available Programming Languages Ready-to-use LabVIEW sample application that provides fast access to controller-based alignment routines as well as visualization and system analysis. User-friendly, platform-independent application development libraries and sample applications for easy, fast, and flexible implementation n Libraries for C++, C#, VB.net, etc. n Python n LabVIEW n MatLab Available for Windows, Linux and OS X deployment. Universal Command Set (GCS) simplifies commis- sioning and programming. Supports PI controllers’ built-in, ultrafast, and vibration-free scan/align algorithms. It is also possible to access the entire command set, including the fast alignment routines in the controller, in order to parameterize and ex- ecute them. This makes it possible for customers to integrate PI controllers into their own software solutions quickly and easily. Python sample code 9 MOTION | POSITIONING FFaasstt MMuullttii--CChhaannnneell PPhhoottoonniicc AAlliiggnnmmeenntt SSyysstteemm SSttaacckkeedd MMuullttii--AAxxiiss SSyysstteemm ffoorr AAlliiggnniinngg FFiibbeerrss aanndd OOppttiiccaall CCoommppoonneennttss F-712.MA1 / F-712.MA2 n I ntegrated scan routines for fiber optic alignment n Ideal for applications in silicon photonics n Extensive software package n Direct detection of the optical signal n P osition sensors for high accuracy and operational reliability n Automatic alignment of several fibers in <1 s Fast and high-precision drives Extensive software package The basis of the optical alignment system is a very stiff XYZ The software package supplied in the scope of delivery allows set-up consisting of three motorized linear stages and a P-616 integration of the system into virtually any environment. All NanoCube® nanopositioner. The low overall height simplifies common operating systems such as Windows, Linux, and OS X integration in limited installation space. The motorized drives as well as a large number of common programming languages make longer travel ranges possible and at the same time, the including MATLAB and LabVIEW are supported. Thanks to NanoCube® nanopositioner ensures fast scanning motion and sophisticated program examples and the use of software tools dynamic compensation of drift effects. Flexure guides and all- such as PIMikroMove, the time between starting integrating and ceramic insulated PICMA® actuators guarantee a long lifetime. productive operation is shortened considerably. Because all drives are equipped with position sensors, it is pos- sible for example, to reliably prevent collisions with expensive High-resolution analog input silicon wafers. The controller receives the optical intensity signal directly via a high-resolution analog input. Complex set-ups with cameras are High-performance scan routines not necessary. Various distribution functions are available for The sophisticated scan routines are integrated directly into the determining the maximum intensity. controller. The performance is improved considerably and inte- gration simplified. The system can manage all tasks in the field Fields of application of fiber alignment. For example, double-sided systems allow Alignment of optical components, automatic wafer tests, assemb- simultaneous alignment of the transmitter and receiver. ling technology in silicon photonics. 10 WWW.PI.WS