Main Differences: 

The U-groove typically has a U-shaped bottom, formed by a dicing process. It is primarily used to prevent UV glue from overflowing onto the lens surface during attachment, reducing the impact of glue on optical performance. It can also serve as an identification mark.

The V-groove has a V-shaped cross-section, formed by wet etching, with an angle of typically 54.74°. It can be used to prevent UV glue overflow and for high-precision alignment, but the cost is higher than that of U-grooves.

OCS 2D TSV Aperture Accuracy: 

SUNA's current 2D TSV array diameter accuracy is 125.75 - 127.25μm (deviation approx. ±0.75μm). Improving aperture accuracy may require process modifications and is subject to technical evaluation by SUNA.

What is the current status of product development?

A 36-channel V-groove standard product has been developed, with pitch accuracy of ±0.3μm.

What are the competitive advantages?

Wet etching has no accumulated tolerance, offering better pitch accuracy compared to glass dicing.

What are the application scenarios for lens-prism assembly?

Used in optical path redirection scenarios such as vertical coupling, while meeting the requirements of multi-channel lens arrays + 45° integrated prisms.

What is the accuracy of the lens array?

ROC tolerance within array: ±1%; pitch accuracy: ±0.3μm.

What are the parameters of the 90° groove for light input/output?

Vertical grooves are opened for both light input and output, with anti-reflective coating to address reflection issues. 90° groove angle: 90°±1°; Groove depth: ≤100μm. Anti-reflective coating can be customized for air or glue. Roughness: <10nm under a 50μm x 50μm test area.

What are the application scenarios for double-sided orthogonal cylindrical lenses?

Used in high-power laser scenarios, suitable for lasers of 350mW and above in CPO applications. Addresses the significant divergence angle difference between fast and slow axes by controlling the X/Y axis spot to improve optical field distribution and enhance signal transmission quality.

Supported Incident Angle Range:

For the 1260-1620nm wavelength range, an incident angle of ±10° is supported. Larger incident angles require evaluation based on wavelength and customer reflectivity requirements.

Etching Process Types and Applications:

SUNA's etching processes include dry etching and wet etching.

Wet etching is used for V-groove fabrication, removing unwanted material via chemical reaction with a solution.

Dry etching is used for silicon/fused silica lens array fabrication, removing material via plasma or other means.

Capability to Fabricate Aspheric Surfaces:

SUNA's silicon/fused silica lens arrays support custom aspheric surfaces and possess the capability to fabricate aspheric lenses.

Design Feasibility of Switching from Quartz to Silicon: Optically, the design is perfectly feasible; from a design perspective, there is no difference in coupling efficiency.

Molded quartz lenses offer better ROC consistency. Silicon lenses require active alignment to compensate for ROC variation.

Silicon has a higher temperature sensitivity of refractive index than quartz. This is not an issue in temperature-stable environments like data centers, but stability under extreme environmental conditions requires further evaluation.

① Pitch Accuracy: SUNA guarantees pitch accuracy of ±0.3μm, measurable via high-precision profilometer. Pitch tolerance and accumulated tolerance: Pitch accuracy is determined by the photomask, lithography, and etching processes; no accumulated tolerance.

Benefits of Improved Coupling Efficiency and Yield: Higher coupling efficiency reduces optical signal transmission loss, improving signal strength and transmission distance in optical communication systems. Higher yield lowers customer procurement costs and enhances the competitiveness of customer products in the market.

To improve coupling efficiency, we select appropriate lenses, assemble them in the most suitable configuration for customers, and apply surface coatings to reduce interfacial reflection. Furthermore, we employ simulation-measurement co-optimization methods to enhance coupling efficiency.

✓ Multiple specifications are capable of mass production.

✓ Mpcs-level orders have been received from global top-tier customers. Currently being delivered in batches.

What is the maximum capacitance value achievable?

Currently, the maximum capacitance for the 0101 size (0.25*0.25mm) is 1nF. Next-generation products are under development, with an expected 51% increase in capacitance.

What is the maximum number of gold wires that can be bonded on the front pad of a 0101 size capacitor?

Internal SUNA testing has verified that with a gold wire diameter of 25μm and a gold ball diameter of 60-66μm, three gold wires can be bonded with normal pull and shear force results.

What packaging options are currently supported?

Standard packaging includes waffle pack packaging and expanded ring frame packaging (supports 6-inch and 9-inch). Custom packaging options are also available per customer requirements.

✓ 67GHz/110GHz+ single-ended and differential broadband capacitors have been released and are capable of mass production .

✓ Mpcs-level orders have been received from global top-tier customers. Currently being delivered in batches.

How to select the capacitance value for silicon capacitors?

Capacitance value is primarily determined by the low-frequency cutoff frequency at -3dB. Based on current experience and considering factors such as capacitance tolerance, voltage, temperature, and aging, a 100nF MLCC commonly used in the industry can be replaced with a 22nF silicon capacitor. Similarly, a 47nF MLCC can be replaced with a 10nF silicon capacitor.

What bandwidth do you recommend for end customers' 1.6T optical module projects?

67GHz meets the requirements for 200G per lane products. 400G per lane requires products with 111GHz or higher bandwidth.

What is the current mounting solution for SUNA's broadband capacitors?

SUNA's standard products come with pre-applied solder paste. The solder paste solution is a mainstream and mature process for optical device mounting at leading SMT companies, offering high compatibility and stable, reliable assembly. SUNA provides a detailed mounting application guide to help customers quickly understand silicon capacitor mounting techniques.

Are 200G per lane samples available?

Yes. Our 67GHz broadband silicon capacitors meet the performance requirements for 200G per lane applications.

✓ 100G per lane IPD (integrated DTC and resistor) for 400G and 800G applications has passed small-batch qualification at multiple customers and is ready for mass production.

✓ Single-ended and differential 200G EML IPD for 1.6T projects is currently in development and tape-out.

What are the main challenges of EML IPD?

IPD has slightly inferior heat dissipation capability compared to ceramic substrates. However, it is far superior in terms of high-frequency loss and product precision, while significantly reducing customer BOM costs.

What are the advantages compared to AlN substrates?

Compared to AlN substrates, discrete capacitors and resistors used in traditional mounting solutions can be integrated onto the silicon substrate, requiring only the EML to be mounted. This greatly improves packaging efficiency. Additionally, silicon offers better flatness and higher process precision, resulting in superior impedance matching performance, better noise suppression, and lower loss.

Advantages compared to broadband MLCCs?

Lower insertion loss at high frequencies (<0.5dB@111GHz). The bottom electrode design also facilitates better PCB trace optimization.

Advantages compared to single-layer ceramic capacitors (SLC)?

Lower ESL and ESR. Smaller size and thinner profile for the same capacitance value, with tighter tolerance (Silicon capacitor: 100μm, SLC: >151μm).

How does the cost compare to ceramics?

Silicon capacitors are currently in the early adoption stage in the optical communication industry. Costs will gradually decrease as market adoption increases.

Standard contract lead time?

6-8 weeks (with forecast), 14-17 weeks (without forecast). For specifications already in mass production, lead time can be shortened to one week if inventory is available. To ensure timely delivery, we recommend placing firm orders in advance. We will prioritize production scheduling based on demand.

Current yield status?

Yield is at the industry average level and is continuously improving with SUNA's in-house process enhancements.