In-House MEMS Chip Fabrication
Photonwares leads the industry in advanced thermal actuated MEMS device design and fabrication. The company operates a 150mm wafer fabrication facility. The 5,000 ft² cleanroom space also serves as new product development, demonstration, integration, and qualification area for outside customers.
Photonwares produces MEMS chips at our in-house MEMS fab facility, located at Woburn headquarter. This capability allows us to reduce the fabrication cost through tight control of manufacturing yield and quality and continuously improve the performance of our MEMS-based products through the combination of design and process improvements. Moreover, we have developed vision-based automatic wafer testing tools that ensure the dynamic performance and quality of each MEMS chip.
Digital 2D MEMS Technology
MEMS-based optical switches can be grouped into two approaches: digital and analog. In both cases, micro-mirrors are actuated to redirect light from a given input port to a given output port. In analog 1xN switches, a mirror is rotated to obtain the switch function, requiring complex feedback electronics with firmware to maintain each coupling position and compensate temperature dependence. These switches have drawbacks of drifting over time due to residual electrostatic charge build-up, which cannot be calibrated by software; slow due to the need to reset after each switching; lost position when power off, and hitless issues.
In digital switches, each mirror only moves within two positions: in or out of the light path. We use a proprietary thermally actuated digital MEMS offering major advantages over analog MEMS. These include high reliability, intrinsic temperature insensitive, no drift over time, fast switching, latching to the positions against vibrations, simple, straightforward electronic driver interface, direct low driving voltage, fail-safe preserving light paths when power removed. Agiltron produces the MEMS chips in our 6” foundry, which enables us to offer the most competitive pricing. A typical MEMS mirror arrangement and principle of operation of a digital optical switch is shown in Figure 2.
Large Motion MEMS Technology
Conventional MEMS are based on electrostatic actuation that is prone to electrical charge build-up induced drift and moisture-induced electrical shorting requiring expensive hermetic sealing. Photonwares’ MEMS is based on the electro-thermal driven actuation principle. Our unique etMEMSTM design provides advantages for fiber optic components, including:
1. Large actuation force over mm
2. Low direct driving voltage <5V
3. A few fabrication steps, high yield
4. No need for a hermetic package
5. Intrinsic tolerance to EDS
Our MEMS switches and VOAs are based on single crystalline silicon, exceptional material that does not deform, fatigue, or wear out over time, and its dimensions and mechanical properties are immune to stress unless a critical fracture stress level or a permanent deformation high temperature is reached. Data results from testing show that Photonwares MEMS switches and VOAs still work within specifications after many billion cycles.