Photonics Packaging Made Visible

Abstract

tially. PICs for optical communication typically use wavelengths between 1 and 2 μm, typically 1550 nm, referred to as C-Band. In applications where visible light is used (400 -700 nm), the use of PICs is emerging and the potential benefits are significant [2 -5]. These applications include several biophotonics applications such as confocal microscopy, flow cytometry, molecular diagnostics, bio sensing DNA sequencing and micro spectroscopy. Moreover, laser based display applications and several (food) sorting applications use visible laser light and will benefit from the use of PICs.The fields of these emerging applications are so broad that no standard packaging scheme, like the fiber pigtailed butterfly package as used in telecommunication, is suitable for all. For example, the complex assembly in Fig. 1 consists of a triangular-shaped fused silica PIC, several fiber arrays and a PCB for electrical interfacing. Furthermore, 45-degree on-chip mirrors are used to guide the light from the center of the PIC into free space. This article will highlight some of the new type of interfaces that are needed for these applications and how they need to be included in next generation packaging standards. PIC technology -TriPleX waveguidesThe technology for photonic ICs is diversified over several materials and processes all targeting specific applications. The main technologies currently used are categorized as silicon photonics, III-V materials and dielectrics. Where silicon photonics and InP, as main III-V material, mainly focus on telecommunication applications at the 1550 nm window, the dielectric materials have the advantage to be transparent for wavelengths below 1 µm. Other advantages that the dielectrics technology platforms offer are the very low optical As PIC technology has a more mature status in the infrared wavelength range around 1550 nm for telecom applications, certain assembly and packaging standards have already been implemented. However, the broad application scope, ranging, for instance, from confocal microscopy to biosensors and display applications, requires a different set of packaging technologies in creating the PIC into a robust and usable product. In this article, we describe -via a set of application examples different options -on how interfaces can be made to PICs for visible light which meets the requirements for these emerging applications.Photonic integrated circuits (PICs) are planar circuits on which several, or even many, optical functions are integrated. Compared to a module with discrete optical components, a module with a PIC will be simpler, more robust, more reliable, more compact and manufacturable in high volumes at lower cost. In addition, the small form factor of PICs serves applications which can impossibly be served with usage of existing discrete components. The primary task for all integrated photonics functions is to transport, manipulate and deliver the laser light to a given target and many functions from well-known discrete optical components can be implemented on a smal...

Integrated Photonics Packaging: Challenges and Opportunities

“…A cohort of packaging techniques have already been adapted to the visible, for example, on the SiN-based TriPlex platform. − Fiber-optic connections to PICs are established using methods similar to those employed for near-IR bands, albeit with tighter alignment tolerances due to the wavelength scaling. Alternatively, visible PICs can also interface directly with free space via polished end facets or etched 45° mirrors Figure illustrates a visible PIC equipped with both fiber-optic and free-space optical interfaces designed to operate as a multicolor laser engine for applications in life sciences. , Light source integration has also been realized, via grating coupling to VCSELs and butt coupling to III–V gain chips …”

“…A cohort of packaging techniques have already been adapted to the visible, for example, on the SiN-based TriPlex platform. − Fiber-optic connections to PICs are established using methods similar to those employed for near-IR bands, albeit with tighter alignment tolerances due to the wavelength scaling. Alternatively, visible PICs can also interface directly with free space via polished end facets or etched 45° mirrors …”

“…Alternatively, visible PICs can also interface directly with free space via polished end facets or etched 45°mirrors. 141 Figure 8 illustrates a visible PIC equipped with both fiber-optic and free-space optical interfaces designed to operate as a multicolor laser engine for applications in life sciences. 142,143 Light source integration has also been realized, via grating coupling to VCSELs and butt coupling to III−V gain chips.…”

Photonic integrated circuits for life sciences

“…In an extended version of the chip, the VOAs have two complementary output ports that are sent to independent sets of wavelength combiners and coupled to one out of two fibers at the output, fulfilling all the functionalities of the commercial MLE represented in figure 1(a). While the lasers are free space coupled to the input of the chip with a pair of lenses, light is directly edge coupled to fibers at the output by attaching a fiber array to the optical subassembly [5]. quency doubled diode laser, FDDL).…”

Transfer-print integration of GaAs p-i-n photodiodes onto silicon nitride waveguides for near-infrared applications

“…The technique also requires III-V processing to be done on top of the circuit wafer. As the current SiN x market is still developing and the application demonstrators are still in the low volume range, the techniques of choice, so far, have been flip-chipping or butt-coupling active components [9]. The downside is that those approaches do not offer a route to scaling towards high-volume or to the dense integration of active components in a cost effective manner.…”