Photonic Integrated Circuit (PIC) Demo Testing Station

PIC Demo Testing Station

Thorlabs offers a variety of components that enable construction of a photonic integrated circuit (PIC) testing station, including imaging systems, fiber optics, precision piezos, and manual stages. This page presents a demo system that drives an on-chip laser and collects and analyzes the emitted light. The laser chip employed in this example PIC testing setup is a fully integrated, heterogeneous GaAs-on-SiN platform with an array of tunable lasers, with each source capable of coarsely covering the range from 765 to 795 nm. This PIC chip was supplied by Nexus Photonics. The scheme of this PIC testing demo can be generalized and customized to meet the needs of testing various PIC chips and is not restricted to the specific circuit used here. Click on the highlighted areas in Figure 787B or the links in Table 787A to find descriptions of the subsystems that comprise the demo testing station. Tables 787C and 787D provide a comprehensive list of all parts used in the demo.

Figure 787B  PIC Testing Demo Setup

Imaging

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Figure 787E  Image of PIC chip, probes, and collection fiber acquired by the imaging system. The lensed fiber used for light collection can be seen in the lower left of the image. The scale bar shows 1 mm.

A widefield imaging system^a is necessary to facilitate alignment of the probe card and light collection (lensed fiber) systems relative to the the PIC chip. Thorlabs' SFM2 Cerna^® Mini Microscope provides a simple means to construct an imaging system^b. An LP126CU Kiralux^® Scientific Camera attached to the SFM2 Mini Microscope displays the image of the PIC chip, probe card, and collection fiber (shown in Figure 787E). Illumination from a light source like the OSL2 High-Intensity Fiber-Coupled Illuminator can be guided to the chip via the OSL2YFB gooseneck fiber bundle. The combination of an MCM301 Stepper Motor Controller and an MCMK3 USB Joystick with the PLSXY and PLSZ Motorized Translation Stages enables three-dimensional motorized control of the imaging system.

1. In this context widefield means an imaging field comparable to the size of the PIC chip.
2. An EF-Mount Adapter Ring such as the SM2CEFM can be used to connect the camera lens to the Cerna microscope.

Cerna® Mini Microscopes	Halogen Fiber Optic Illuminators	Gooseneck Fiber Bundles	EF-Mount Adapter Rings	Kiralux® Scientific Cameras	Compact Stepper Motor Controller	Joystick for Stepper Motor Controller

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Figure 787F  PIC Chip Close Up Showing Probe Card, Collection Fiber, Illumination, and Imaging Microscope

Light Collection

Figure 787F shows a close up of the light collection geometry. Light emitted from the chip is collected by an LFM1F-1 Lensed Multimode Fiber and coupled into an optical spectrum analyzer (as discussed in the previous section). If multiple facets of analysis are desired, the signal can be split using a multimode fiber optic coupler such as the TM50R2F1B. To achieve adequate signal-to-noise ratio, fine positional control of the collection fiber is necessary. Thorlabs offers many components enabling precision control of fiber optics. Thorlabs' NanoMax™ line provides precision fiber positioning, and a PY004 base allows pitch and yaw control. The NanoMax MAX311D contains piezos, which can be controlled for auto-alignment with a combination of the KNA-VIS and KPC101 K-Cube^® Controllers. The KCH301 and KCH601 K-Cube mounts are available as a USB hubs for the K-Cubes.

Lensed Multimode Fibers	Multimode Fiber Optic Couplers	NanoMax™ Fiber Flexure Stages	High-Load Pitch and Yaw Platform	K-Cube Auto-Alignment Controllers	K-Cube Piezo Controller	K-Cube USB Controller Hubs

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Figure 787G  Screenshot of Spectrum Acquired with the OSA202C

PIC Control and Readout

In order to drive the laser circuit on the chip, current is supplied to the PIC chip via the probe card. Two LDC202C Laser Diode Drivers serve as the current sources here. Emitted light collected from the chip is directed into the fiber-coupled OSA202C Optical Spectrum Analyzer, which provides analysis and display of the signal. Figure 787G shows an example screenshot of the spectrum acquired by the OSA202C.

Depending on the particular PIC chip/testing application, various beam characterization and polarization measurement instruments can be used to construct a custom analysis setup to meet specific needs. Examples include the CCT10 Compact CMOS Spectrometer for spectroscopy, the PNA1 Intensity Noise Analyzer for high frequency-axis noise analysis, and the PAX1000IR1 Polarimeter for polarization measurements.

Laser Diode Drivers	Optical Spectrum Analyzers	Compact CMOS Spectrometers	Intensity Noise Analyzer	Polarimeters

Positioning

MVS05 Vertical Translation Stage	XRV1 Vertical Translation Stage	Compact X-Y Translation Stages

PIC Chip Stage

Vertical (Z-axis) control of the PIC chip aids in focusing the widefield imaging system. A vertical drive stage such as the MVS05 Stage provides this additional degree of freedom. If more range is needed, the MVS1 Vertical Translation Stage allows up to 1" of travel.

Probe Card

The probe card serves to supply a multipoint electrical contact directly to the on-chip devices. To achieve optimal/flush contact with the chip multiple degrees of freedom are necessary. A vertical translation stage such as the XRV1 Stage provides vertical translation, and the LX20 Stage allows XY translation.

Thorlabs offers a wide selection of manual stages including linear translation, rotation, and multi-axis stages.

Optical Tables, Breadboards, and Supports	Solid Aluminum Breadboards	ScienceDesk Workstations	ScienceDesk Shelving	Cable Management

General Setup, Organization, and Cable Management

Thorlabs offers a wide selection of general components and tools for construction, organization, and management of a PIC testing station. Optical tables, breadboards, and supports provide the foundation of any testing setup. ScienceDesk™ workstations can provide a convenient means to construct a vibration isolated table with a small footprint, and shelving affords convenient options for holding tools, equipment, and instruments. Cable management products for electric and fiber optic cables are also available.

Custom Capabilities

Both the lensed fiber holder and probe card holder were custom made for this specific PIC testing station demo application. Thorlabs offers a wide variety of custom solutions and manufacturing capabilities for various applications. Contact techsales@thorlabs.com for further information.