The modular NanoTrak Auto-Alignment Controller combines an intelligent active-feedback alignment control system and a two channel piezoelectric controller into a single plug-in unit. As part of the APT series, this autoalignment system represents the latest developments in automated optical alignment technologies. This system is a basic building block from which advanced alignment systems can be quickly configured. It can be fully integrated into a rack system that is comprised of a selection of our plug-ins: piezoelectric controllers, stepper motor controllers, and this NanoTrak autoalignment module. The Controller is available with InGaAs (800 - 1800 nm) or Si (320 - 1000 nm) detectors.

The initial coupling of light from one device (e.g. fiber) to another involves searching a multidimensional space until a signal is detected. The NanoTrak™ support software offers a series of motor search algorithms for this first light detection. Although used primarily for aligning optical fibers and integrated optical devices, the NanoTrak is ideal for automating just about any labor intensive alignment tasks such as waveguide characterization, fiber pig-tailing of active and passive devices, as well as a multitude of other R&D applications.

Module Specifications

Optical Detector Specfications

NanoTrak Connector

Piezo Connector

Principal of Operation

During the auto-alignment process, the NanoTrak uses gradient search algorithms to locate the direction of a peak signal. This operation is similar to that of a compass finding the north-pole. The sensitivity of the search is such that even with small power gradients (far away from peak signal) the NanoTrak will decide in which direction the peak signal is located. This information can then be used to make positional corrections with attached high speed piezo actuators, without having to map or search a large area.

In the proximity of a peak signal, the signal gradient seen is much smaller, indicating that smaller positional correction is required. When peak signal is reached the gradient seen changes to zero, indicating that no positional correction is needed.

The dynamic behaviour of the NanoTrak allows it to continue the alignment process indefinitely. Should the alignment change, the gradient search will detect the change and make a corrective move.

Typical Application Example (Optical Device Alignment)

Optical power transmission through any system under alignment can be described as a Gaussian coupling. Coupled power decreases as a function of distance relative to the aligned position, which is dependent upon the alignment device used. Discrete power level alignments can be thought of as positions about the ideal coupling position where the distance from the aligned position are equal. These descrete power alignment positions form concentric cricles. These concentric circles represent the power contours and can be thought of as the gradient contours of a hill on a map.

By detecting the gradient of the power at any given position, the NanoTrak can adjust the position until the power is maximized and the gradient becomes zero. This is achieved by scanning over the contours in a circular path to establish the direction of the signal maximum on the circular trajectory. The origin of the scan circle is then moved in the direction of the signal maximum.

Continuous active alignment can used to maintain alignment, or the search algorithms can be halted for next step assembly or R&D operations.

The APT (Advanced Positioning Technology) family covers a wide range of motion controller products ranging from small low powered single channel optomechanical motor drivers (the 'Cube' drivers) to high power multi-channel modular 19" rack nanopositioning systems (the APT Rack System).

All controllers in the APT family share a common software platform, the APT System Software. The software CD supplied with all controllers contains an installation of this system software, together with a wealth of support information in the form of handbooks, help files, tutorial videos, FAQs and other relevant information on using and programming these Thorlabs products.

By providing this common software platform, Thorlabs has ensured that users can easily mix and match any of the APT controllers in a single application while only having to learn one single set of software tools. In this way it is perfectly feasible to combine any of the controllers from the low powered single axis to the high powered multi-axis systems and control all from a single PC based unified software interface.

The APT System Software allows two methods of usage - graphical user interface utilities (supplied) for direct interaction and control of the controllers out of the box, and a set of programming interfaces that allow custom integrated positioning and alignment solutions to be easily progammed in the development language of choice.

Typical APT User GUI

Typical Configuration Screen

Detailed information on both usage modes is provided on the CD.

Also of particular interest is the inclusion on the software CD of a range of software video tutorials (see the Video Tutorials tab). These videos illustrate some of the basics of using the APT System Software from both a non-programming and a programming point of view. There are videos that illustrate usage of the supplied APT utilities that allow immediate control of the APT controllers out of the box. There are also a number of videos that explain the basics of programming custom software applications using Visual Basic, LabView and Visual C++. 

Click here to go direct to the Thorlabs Download Area to access the full APT software CD. Experiment with the software using the simulator mode - refer to the Tutorial Videos for the APTConfig utility to learn how to select simulator mode.

These videos illustrate some of the basics of using the APT System Software from both a non-programming and a programming point of view. There are videos that illustrate usage of the supplied APT utilities that allow immediate control of the APT controllers out of the box. There are also a number of videos that explain the basics of programming custom software applications using Visual Basic, LabView and Visual C++. Watch the videos now to see what we mean.

Click here to view the video tutorial

To further assist programmers, a guide to programming the APT software in LabView is also available.

Click here to view the LabView guide