The electrostatic force-based VOA mirror adjustment can be applied in 100G DR4 40km applications to cooperate with SOA for signal amplification at the receiver end.
The electrostatic force controls the suspension beam.
The formula for static electricity is as follows.
Reducing d to bring the comb teeth closer increases the static force, which enhances efficiency and reduces power consumption. However, if the distance is too close, the process requirements become more stringent. Moreover, during the application, it is necessary to avoid debris from the optical assembly process that can easily fall into the gap between the teeth and cause the mirror to get stuck.
To address this issue, a dustproof cover has been added to the VOA package. The main optical path window is used for optical signal channels, and other positions form a debris shielding structure.
The design can help dustproofing and improving the VOA's reliability. Meanwhile the light-through hole's shielding design can reduce the optical crosstalk of the RX receiver and improve agility.
The angle of reflection of the VOA is deviated from the light path, and the light energy in the main light path is related to the VOA mirror's angle. Essentially, the light is not "attenuated," and the remaining light that deviates from the optical path will be diffusely reflected throughout the cavity, resulting in crosstalk of the optical path at the receiving end and causing sensitivity degradation.
The dust cover's effect is to absorb or block additional diffuse light, which can alleviate the performance degradation caused by crosstalk.
XINXIN GEM provide TO-33 Caps for Mems Mini VOA.
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