In an interview with PIC Magazine, Al Cheswick, President of Krell Technologies, explained how the company has evolved its polishing systems and approach to address the needs of the photonic integrated circuit (PIC) industry and shared what innovations are next. 

From Telecom to Advanced Photonics 

Founded over 30 years ago, Krell Technologies first supplied polishing equipment for telecom and datacom applications such as patch cords and cable assemblies. These solutions were developed to meet strict industry standards like IEEE and Telcordia. Over time, KrellTech expanded its technology to serve avionics, defense, and medical device markets, adapting its solutions to meet the tighter specifications required for precision optics in new industries. 

Building a Product Line for PIC Manufacturing 

About twelve years ago, KrellTech began its first waveguide polishing project, which started its path into PIC-focused solutions. The first system designed for this purpose was the FLex machine, created to give researchers high flexibility to adjust polishing parameters for new PIC and waveguide designs. 

Recognizing a need for greater automation, KrellTech introduced the NOVA polishing system six years ago. NOVA offers a more automated approach than the FLex. It includes tablet control, a programmable user interface, automated axes and in-line video inspection. NOVA is now the foundation of KrellTech’s dedicated PIC product line. 

Why Polishing Quality Matters for PICs 

Although polishing is not as publicly visible as other advanced photonics fields, it plays a critical role in maximizing PIC performance. High-quality polishing improves coupling efficiency between components and reduces reflectance losses. KrellTech’s systems help achieve superior surface finishes and precise geometry control. The company describes its process simply: shape, polish and inspect. 

Unique Features of KrellTech’s Approach 

One standout feature is the fixture used for polishing. The fixture has interchangeable clamps that allow it to handle various chip sizes, which is important during research phases when final chip dimensions are not yet defined. It also supports multiple polishing angles, whether flat or angled finishes are needed. 

Each chip position on the fixture has independent suspension with freedom of movement in the Z-axis. This ensures equal pressure distribution so that each chip achieves a uniform polish. Fixtures are calibrated using interferometric alignment so each polishing point is square and accurate. 

KrellTech’s machines include manual and programmable modes. Engineers can quickly test new parameters and transfer successful recipes to programmable workflows for production. The system allows for precise Z-axis movement, with automated positioning down to five microns and manual control to one micron when needed. Real-time stock removal monitoring and in-line inspection are also integrated so parts can be polished, checked, and adjusted without transferring them between separate stations. 

Preparing for Higher Volumes and Diverse Materials 

As the industry shifts from research to production, KrellTech supports scalability through methods like the carrier approach. In this model, chips are preloaded offline into carriers that can be mounted in multi-position fixtures. This enables users to polish more chips simultaneously once the design is fixed. 

KrellTech has processed many materials including silicon, silica, silicon dioxide, lithium niobate, sapphire and various hybrid combinations. Each new material requires custom process development. KrellTech’s long experience helps shorten this development cycle for new customers. 

Partnering with the Industry and Planning for the Future 

KrellTech works closely with its customers and organizations like Advancing Photonics Technologies to share knowledge and keep pace with new requirements. It also collaborates with local colleges for internships and uses shared facilities for testing when needed. 

Looking ahead, KrellTech plans to integrate more robotic handling, smart vision systems, and automated inspection with data-driven feedback. The goal is to support the growing need for high-volume, high-accuracy PIC production within the next five years. 

Full Transcript: Al Cheswick Interview with PIC Magazine 

0:09 
Hello, all. 

0:10 
Thank you for joining us today. 

0:13 
You are from KrellTech, so for people who might be unfamiliar with the company, could you please briefly outline the range of products that you offer to support the PIC industry? 

0:23 
Yeah, sure. 

0:24 
Hi, Laura. 

0:25 
Thanks for the opportunity to discuss our product line and our technologies. 

0:31 
Krell Technologies. 

0:32 
We have been in business for over 30 years and when we first established ourselves, the markets we were addressing were telecom, datacom and like cable TV and the products we supplied, the polishing equipment was basically supporting patch cords, cable assemblies, basically commodities that had standards that had to be met, industry standards like IEEE Telcordia. 

1:02 
But over the years as fiber, I mean fiber, but optics had integrated into much more broad applications such as avionics defense, and that is defense with a C for you and it is the UK way. 

1:20 
And then things like sensing medical devices, our product line had to evolve to meet those new specifications that come with those types of products. 

1:31 
But about roughly 10 years ago, I mean more like 12 years ago, we had our first project that came to us regarding processing waveguides and PIC type products. 

1:45 
At that point in time, we did not have an actual product line, so we had to develop it based on that. 

1:52 
And we started with a machine called our FLex machine, which gave high flexibility in terms of its name itself to researchers that were developing new PICs and waveguides at that time, with capabilities of changing a lot of polishing parameters to process their chips in a certain way that met their new forthcoming requirements. 

2:20 
It was a very manual machine back then, about 10 years ago. 

2:24 
So we had to evolve that one into something more automated. 

2:27 
So six years ago, we introduced our NOVA polishing system, which was a more automated version of the original FLex, where it is tablet controlled, programmable user interface, automated axes and in-line video inspection. 

2:45 
So that really, like I said five to six years ago, established what we were going to build our PIC product line on at that time. 

2:54 
And that is what we have been going forward with. 

2:57 
That is really interesting how the company's products have evolved as this new market emerged. 

3:02 
Well, yes, you have to do that. 

3:04 
And you know, nowadays, like I said, we initially started in that telecom datacom market. 

3:09 
That is probably less than 10 percent of our business now. 

3:13 
I mean PICs have become in terms of inquiries, probably 50 percent of all our new inquiries are related to the PIC waveguide industry. 

3:26 
And that just shows how the industry is growing. 

3:30 
Could you expand on how important polishing technology is to achieving high performance for PICs across all their applications? 

3:41 
Well, polishing is the nitty gritty of the PIC world. 

3:45 
It is not like quantum computing or photon entanglement. 

3:51 
It is polishing, grinding and shaping types of objects. 

3:56 
But it is important for PICs in terms of maximizing performance. 

4:02 
That means improving coupling efficiency between components and minimizing reflectance. 

4:12 
All of that is accomplished by using a machine that yields superior surface finishes and geometry control. 

4:22 
We like to sum it up this way: we shape, polish and inspect the PICs. 

4:32 
Polishing is very critical. 

4:36 
We often receive samples from universities for projects and many samples arrive in what we call a post dicing condition. 

4:52 
The surface finishes are usually quite poor. 

4:58 
So before you can even polish those components, you have to coplanarize them. 

5:04 
After that, you can move forward. 

5:06 
So polishing is integral to PICs. 

5:11 
Absolutely. 

5:13 
Especially as they transition from academia to commercialization, it becomes essential for reliability. 

5:21 
And that is an issue we run into now. 

5:25 
Could you tell me what is unique about KrellTech's approach to polishing and what advantages it offers for PIC manufacturing? 

5:35 
Sure. 

5:39 
A big advantage of our products is in the fixture itself. 

5:47 
This is a sample of a waveguide polisher. 

5:55 
It has four positions so you can mount four chips on it. 

6:00 
It has interchangeable clamping mechanisms for different size chips. 

6:08 
This means one fixture can handle a variety of chip sizes, which is important in research because final shapes or sizes are not always known. 

6:21 
It also allows for different geometries, flat or angled polishes. 

6:37 
Our fixtures support this flexibility at the research and development stage. 

6:53 
They also have independent suspension. 

6:57 
Each position can move independently in the Z-axis. 

7:03 
This equalizes the pressure during polishing, so each chip gets the same polish. 

7:24 
It ensures that all chips stay in contact with the film, preventing skips. 

7:32 
These features make our fixtures quite sophisticated. 

7:39 
Each position has a ball and socket joint for fine adjustments. 

7:50 
We adjust each position in our calibration lab using interferometric tools to ensure each point is square with the polishing surface. 

8:08 
This gives superior geometry control. 

8:32 
The machine itself has different operating modes, manual mode for quick development and programmable mode for production. 

8:55 
It offers automated Z-axis positioning down to five microns and even one micron in manual mode. 

9:09 
Controlling stock removal is important so you polish to the right depth without damaging the light guides. 

9:30 
Our systems include real-time monitoring and in-line inspection while chips remain loaded. 

9:55 
This prevents unnecessary handling and reduces breakage risks. 

10:07 
The work cell approach lets users polish, monitor and inspect in one machine. 

10:30 
This supports both development and production. 

10:35 
Could you describe some challenges involved in polishing and how KrellTech addresses them? 

10:47 
Challenges include loading components consistently, clamping without damaging sensitive areas, and handling chips of different sizes. 

11:21 
This often requires custom fixture design. 

11:29 
Other challenges are achieving good surface finishes, managing edge geometry and maintaining precise angles and removal rates. 

11:56 
We use our extensive database and experience but each new project brings unique issues. 

12:11 
As PICs evolve and integration density increases, does this create new polishing challenges? 

12:22 
Not necessarily in density but more in scaling up to higher volumes. 

12:43 
Researchers need flexible fixtures which take up space and limit the number of chips that can be polished at once. 

13:07 
Once designs are fixed, we use a carrier approach where chips are preloaded offline into carriers. 

13:48 
Carriers allow polishing more chips at once but with less variability. 

14:28 
We also expect higher volume requirements and plan to add robotics and smart vision systems. 

14:55 
We want to be ready within five years. 

15:12 
Do different PIC materials require different techniques? 

15:27 
Yes, materials vary: silicon, silica, silicon dioxide, lithium niobate, sapphire and hybrids. 

15:47 
Process development is essential and includes testing abrasives, pressures, speeds and cycles. 

16:09 
Our experience helps but each project has unknowns. 

16:23 
About half the work is fixture design, half is process development. 

17:03 
Customers often improve performance further using our tools. 

17:24 
The equipment is straightforward to learn but flexible enough for innovative development. 

17:37 
How does KrellTech work with partners like PIC foundries? 

17:49 
Our main partners are our customers. 

18:04 
We share knowledge, generate and test samples together. 

18:24 
We also collaborate with Advancing Photonics Technologies and regional colleges for shared testing and internships. 

19:16 
Looking ahead, what PIC innovations is KrellTech excited about? 

19:30 
Our next generation equipment will have more robotics, advanced inspection, feedback and analysis. 

20:09 
This will support production lines. 

20:33 
Our engineers are eager to work on new robotics and scratch analysis tools. 

20:41 
We want to be ready within five years. 

20:52 
Thank you for joining us. 

20:55 
Thank you, Laura. 

Learn More 

If you are developing or manufacturing photonic integrated circuits, waveguides or optical interconnects, KrellTech’s NOVA system offers the precision and flexibility needed from R&D to production. 

Watch the full interview 
Explore the NOVA Polishing System 
Contact sales@krelltech.com