Assessment of Surface Finish on Stamped Mirrors of Metallic PIC Connectors (MPC)

Introdução

The development of high-performance photonic integrated circuits (PICs) has driven the need for advanced optical connectivity solutions. Metallic PIC Connectors (MPCs) utilizing micro aspherical mirrors are an emerging technology that facilitates efficient optical coupling. The quality of these mirrors, particularly their surface finish, is critical for ensuring low optical loss and high signal integrity.

Precision optics require exceptional surface finish and low roughness to ensure optimal light reflection and transmission. The MPC Connector’s micro aspherical mirrors, produced through an advanced stamping process, achieve optical quality without the need for post-processing. This article presents an evaluation of the mirror finish in an 8×1 stamped mirror array and discusses its implications for high-performance optical connectivity.

 

Optical Quality of Stamped Micro Aspherical Mirrors

A detailed surface finish assessment of the stamped mirror array for 1310nm and 1550nm optical wavelengths reveals several key attributes that contribute to its high optical performance. Notably, the mirrors achieve exceptional results directly from the stamping process without the need for any post-processing. This not only simplifies the manufacturing workflow but also ensures that the mirrors maintain their precise geometrical features as intended from the initial design.

Uniform reflectivity across the mirror array is another significant outcome. This uniformity is crucial for consistent light steering across all mirrors in the array, ensuring that the optical signals are transmitted with minimal loss and high fidelity. Moreover, the highly controlled geometry maintains precise aspherical curvature, which is essential for optimal beam shaping and focusing. This accurate curvature is vital for reducing spherical aberration and enhancing the efficiency of optical signal coupling.

Statistical Distribution of Surface Roughness Attributes

The surface finish measurements, obtained using a scanning white light interferometer, reveal critical parameters that underscore the quality of the stamped micro aspherical mirrors.

Firstly, the Sa (Areal Arithmetic Average) represents the average height deviations across the mirror surface. This metric provides a comprehensive overview of the surface texture by calculating the mean of all the absolute differences between the actual surface and an ideal flat plane. A low Sa value indicates a smoother surface, which is essential for minimizing scattering.

Secondly, the Sq (Areal Root Mean Square – RMS) quantifies the statistical distribution of surface irregularities. This measurement is particularly insightful as it considers the square of the height deviations, thereby giving more weight to larger deviations. A lower Sq value suggests that the surface has fewer and less severe irregularities, enhancing the mirror’s ability to maintain high optical performance and reducing the likelihood of scattering losses.

Lastly, the overall low roughness values observed in these measurements demonstrate the suitability of these mirrors for high-efficiency optical coupling. The low roughness ensures that the mirrors can effectively reflect optical signals with minimal aberration. This characteristic is vital for applications requiring precise optical signal transmission, as it contributes to maintaining high signal fidelity and reducing insertion loss.

The impeccable surface quality achieved through the advanced stamping process, as evidenced by these low Sa and Sq values, highlights the MPC’s potential in high-performance photonic integrated circuits, where maintaining signal integrity is paramount.