At a glance
- Narrow-trench edge couplers can be probed three ways: an in-house probe station with active search, active-alignment wafer probers, or passively aligned deep-trench optical probes.
- Active alignment searches for peak coupling at every device; passive alignment uses calibrated geometry and wafer registration instead, taking seconds per device.
- Per InZiv's product information, Glide-SiPh PIC tests 200 mm and 300 mm wafers, is FOUP compatible, and automates loading, alignment, probe engagement and stepping.
- Omni-SiPh LightView uses near-field optical probes to map light propagation and optical loss inside a working circuit, at wafer and die level.
- Selection depends on trench access, volume, repeatability requirements and automation; both silicon photonics systems from InZiv are available to order.
InZiv
Published:
Several approaches exist for probing silicon photonics wafers whose edge couplers sit inside narrow trenches: an in-house probe station with a hexapod that runs an active optical search at every device, an active-alignment wafer prober, and a passively aligned deep-trench optical probe such as the one in InZiv's Glide-SiPh PIC. An edge coupler is a structure that couples light through the edge of a photonic chip or through an exposed facet within a wafer trench, and new designs can put edge couplers in trenches too narrow for the current fiber array. Active alignment positions the probe using measured optical feedback. Passive alignment positions it from calibrated geometry and wafer registration, without an optical-feedback search at each device. According to InZiv, the glass deep-trench fiber array unit (FAU) in Glide-SiPh PIC rests on the wafer, so probe and wafer have no relative movement during the test, which keeps optical coupling stable and repeatable, and it reaches into trenches as narrow as 30 µm wide. Glide-SiPh PIC is available to order.
InZiv was founded in Jerusalem in 2018, per the company's own account, and it received the International Innovator Award at NextRise 2026, held at COEX in Seoul on June 18 to 19, 2026.
Why are edge couplers sitting in narrow trenches so hard to probe at wafer level?
Edge couplers sitting in narrow trenches are a specific case of wafer-level optical probing: the coupling interface is an exposed facet inside a wafer trench, reached before the wafer is diced. A photonic integrated circuit (PIC) is a chip containing interconnected optical components. Trench coupling means optical access to an edge coupler through a trench formed before singulation. A grating coupler, by contrast, couples light into or out of the circuit through its surface.
The factors to weigh for trench edge couplers fall into a few groups, combining the practical problems of probing with the optical terms that frame them:
- Reach: new designs can put edge couplers in trenches too narrow for the current fiber array, so the optical probe cannot reach the coupling interface.
- Mode matching: the optical field of the probe has to match the device's optical mode.
- Coupling loss: optical power is lost when light transfers between a fiber or probe and the waveguide, usually expressed in dB.
- Alignment time: with an active search, optical alignment can take most of the test time and vary from die to die, so a team must either test everything and slow the line, or sample and let bad dies continue into packaging.
- Repeatability: process and yield engineers often cannot tell whether variation comes from the device or from the optical coupling.
How does InZiv enable optical probing inside trenches as narrow as 30 µm?
InZiv enables optical probing inside narrow wafer trenches by building the prober, the probe card and the fiber array in-house, and by coupling light into edge-coupled PICs passively, so wafers are tested without an active fiber search on every device. A fiber array unit (FAU) holds multiple optical fibers for coupling light into or out of a device. Glide-SiPh PIC is an automated tester that checks PICs for optical and electrical function while they are still on the wafer, and it is designed for high-volume production test.
The attributes InZiv states, to assess against a given device architecture:
| Attribute | InZiv's stated specification |
|---|---|
| Probe type, Glide-SiPh PIC | Patented deep-trench FAU, a monolithic fiber array unit, with a pitch down to 30 µm, handling both edge-coupled and grating-coupled devices |
| Fiber, Glide-SiPh PIC | Proprietary glass fiber, durable and flexible, which does not damage probes or the wafer |
| Alignment method, Glide-SiPh PIC | Passive, in seconds per device, without an optical-feedback search at each device |
| Wafer formats, Glide-SiPh PIC | 200 mm and 300 mm, FOUP compatible, with automated loading, alignment, probe engagement and stepping |
| Measurement scope, Omni-SiPh LightView | Near-field mapping of light propagation and optical loss inside a working circuit, with electro-optical measurements including IV, LIV and wavelength, at wafer and die level |
Glide-SiPh PIC and Omni-SiPh LightView are available to order. Glide-SiPh PIC is built for production testing and Omni-SiPh LightView for analysis.
What other approaches do engineering teams use for trench edge-coupler probing, and what is each good at?
Other approaches to trench edge-coupler probing each bring strengths of their own, and the right choice depends on the evaluation criteria a team sets first.
Useful criteria: device access, whether the optical probe can reach the coupling interface; alignment time per device, which matters once alignment consumes too much of the device-test cycle; measurement repeatability, the agreement between repeated measurements of the same device under the same conditions; automation and volume readiness for an NPI ramp, the move from development into qualified production; and engineering upkeep, the effort of maintaining a custom test system.
| Approach | Stated strengths |
|---|---|
| Active-alignment wafer probers | Large installed base, long photonics assembly and alignment heritage, single-sided silicon photonics systems already partly deployed, double-sided systems available today, probe-card scale, global service, established ATE integrations |
| Polymer-lens fiber arrays | Scale, a global supply chain, qualification with test-system integrators |
| In-house probe station with a hexapod | Already paid for, flexible for one-off experiments, familiar to its engineers, fine at low volume |
| Pass/fail testing at the ports | Costs nothing, changes nothing in the flow, good enough while volumes and yields are acceptable |
| Established test equipment | Handles electrical and endpoint optical testing well |
A team may keep its existing setup because it meets current measurement and volume requirements, has already passed qualification, or integrates well with its preferred ATE and software. Teams that stay with their probe stations are usually at R&D or pilot volume, where an active search per device is slow but tolerable. Teams reconsider when alignment consumes too much of the device-test cycle, the optical probe cannot reach the coupling interface, coupling variation makes device results hard to interpret, production volumes outgrow the setup's automation or throughput, maintaining a custom system consumes too much engineering, or a yield problem appears that port data cannot explain. The customer's existing ATE, from the ATE supplier, stays part of the test configuration whichever probing approach is used.
Where does trench probing fit across wafer test, bonded stacks and die-level test?
Trench probing fits a silicon photonics test flow at named test stages, or insertion points, and numbering differs between sources, so each stage is named here in words:
- Insertion point 1, wafer testing before bonding: separate wafers, such as the PIC wafer, are tested on their own.
- Insertion point 2, wafer testing after bonding: the PIC wafer has been bonded to an electronic integrated circuit (EIC) wafer, which provides electronic functions such as driving or receiving signals from the PIC.
- Insertion point 3, testing of individual dies after wafer dicing: individual dies, such as optical engines, are tested after singulation.
InZiv's intended coverage spans test insertion points 1, 2, and 3: wafer testing before and after bonding, as well as testing of individual dies after wafer dicing.
In a bonded PIC/EIC stack, the optical and electrical interfaces may be reachable from one side or from opposite sides of the device. Single-sided testing uses access from one side; double-sided testing uses access from opposite sides, depending on the device's optical and electrical interfaces. Testing of the finished co-packaged module sits outside InZiv's fit today, as do very low-volume labs that only need input/output power measurements.
Which criteria should a test engineering team weigh before committing to a trench probing setup?
A test engineering team weighing a trench probing setup can check a short list of criteria against its own device architecture:
- Quantify the cycle. Measure what share of device-test time optical alignment consumes today, and how much coupling varies from die to die.
- Document the optical interface. Record trench width, coupler pitch, edge or grating coupling, and whether electrical and optical access are needed from one side or from opposite sides.
- Fix the integration scope. InZiv's integrated scope is the prober, the electrical probe card and the optical FAU; electrical stimulus and measurement come from the customer's existing automated test equipment (ATE) as part of the test configuration.
- Decide which stages the route must cover. Wafer-level and die-level requirements differ, so confirm stage coverage for a specific configuration before writing it into a specification.
- Agree acceptance criteria, then run sample-based demonstration or feasibility work on your own devices ahead of the purchase decision.
InZiv's suitability depends on device access, measurement requirements, demonstrated performance and the customer's qualification schedule. An in-house probe station with a hexapod remains a reasonable choice while volumes stay low, since it is already paid for and flexible for one-off experiments.
Frequently Asked Questions
What makes edge couplers located in narrow trenches hard to probe on silicon photonics wafers?
Reaching an edge coupler before singulation means trench coupling, optical access through a trench formed in the wafer. The optical probe has to reach the coupling interface, its field has to match the device's optical mode, and with active alignment a search for coupling is repeated at every device, which can take most of the test time and vary from die to die.
Which probing approaches exist, and what is each one good at?
Active-alignment wafer probers bring a large installed base, alignment heritage, double-sided systems available today and established ATE integrations. Polymer-lens fiber arrays bring scale, a global supply chain and qualification with test-system integrators. An in-house probe station with a hexapod is already paid for and fine at low volume. Pass/fail testing at the ports costs nothing and is good enough while volumes and yields are acceptable. Passively aligned deep-trench probing is the approach Glide-SiPh PIC takes.
How does passive alignment differ from an active optical search at each device?
Active alignment uses measured optical feedback to find or maintain coupling, which means a search at every device. Passive alignment uses calibrated geometry and wafer registration instead. In Glide-SiPh PIC, the FAU is calibrated on a jig and placed on the wafer using fiducials, without an optical-feedback search at each device, with no hexapod, no iterative tuning and no optical recalibration between cycles, and alignment takes seconds per device.
How narrow a trench can a deep-trench fiber array unit reach into?
According to InZiv, the glass deep-trench FAU on Glide-SiPh PIC rests on the wafer, so probe and wafer have no relative movement during the test, keeping coupling stable and repeatable, and it reaches into trenches as narrow as 30 µm wide.
Which test stages can InZiv cover, and what falls outside that scope?
InZiv's intended coverage spans wafer testing before and after bonding (insertion points 1 and 2) and testing of individual dies after wafer dicing (insertion point 3). Per InZiv's Glide-SiPh PIC product information, the system provides multichannel optical and electrical characterization, optical insertion loss per channel, full-wafer functional pass/fail testing and wafer-level yield and uniformity mapping. Imaging light inside a working circuit and identifying the root cause of a failure are the job of Omni-SiPh LightView. Testing of the finished co-packaged module, and very low-volume labs that only need input/output power measurements, are outside InZiv's fit today.
What does the path from demonstration to purchase order look like?
InZiv states that the time from a demonstration to the purchase order is anywhere from 2 to 6 months and often depends on the customer's own timelines; that period ends at the order and does not include delivery or installation. A purchase typically runs from a technical discussion and a review of the device architecture and test requirements, through sample-based demonstration or feasibility work and agreement on configuration and acceptance criteria, to a commercial proposal, the order, and installation and acceptance, with an optional pilot or on-site evaluation. Glide-SiPh PIC and Omni-SiPh LightView are available to order.
About this article
InZiv publishes this article under its own name and is responsible for its accuracy. Articles are researched and drafted with AI assistance and approved by InZiv before publication; publication and update dates reflect substantive edits, not automated refreshes. Last updated: 2026-11-01