Optical connection of optical fibers to grating couplers

Abstract

To couple light between an optical fiber and a grating coupler of a photonic integrated circuits, a mirror is provided to turn light to / from the optical fiber to allow the axis of the optical fiber to be oriented at small angles or parallel to the surface of the PIC, and lowered close to the surface of the PIC. The mirror is further configured to reshape light from a flat polished optical fiber to produce a mode field resembling the mode field of an angled polished optical fiber, to match the design angle of existing grating couplers that are designed to work with angled polished optical fibers. The mirror and optical fiber alignment structure in the optical connector are integrally / simultaneous formed by precision stamping.

Description

PRIORITY CLAIM[0001]This application (1) claims the priority of U.S. Provisional Patent Application No. 61 / 994,089 filed on May 15, 2014, and (2) is a continuation-in-part of U.S. patent application Ser. No. 14 / 695,008 filed on Apr. 23, 2015, which is a continuation-in-part of U.S. patent application Ser. No. 13 / 861,273 filed on Apr. 11, 2013, which (a) claims the priority of U.S. Provisional Patent Application No. 61 / 623,027 filed on Apr. 11, 2012; (b) claims the priority of U.S. Provisional Patent Application No. 61 / 699,125 filed on Sep. 10, 2012; and (c) is a continuation-in-part of U.S. patent application Ser. No. 13 / 786,448 filed on Mar. 5, 2013, which claims the priority of U.S. Provisional Patent Application No. 61 / 606,885 filed on Mar. 5, 2012. These applications are fully incorporated by reference as if fully set forth herein. All publications noted below are fully incorporated by reference as if fully set forth herein.BACKGROUND OF THE INVENTION[0002]Field of the Invention...

AI Technical Summary

Benefits of technology

The present invention provides a new way to connect an optical fiber and a grating coupler in a photonic integrated circuit (PIC). A mirror is used to redirect light from the fiber to the coupler at small angles, making the connection low-profile and suitable for smaller transceivers. The mirror and fiber alignment structure are formed by precision stamping, which improves tolerance, manufacturability, ease of use, functionality, and reliability. The technical effects include better connection performance and economical production.

Problems solved by technology

Consequently, the PICs cannot be tested on a wafer and must be packaged before determining whether a PIC is good or bad.

This increases production cost for the PICs and requires stringent alignment tolerances between the optical fiber and the polished end of the waveguide.

However, prior art using grating couplers has at least two major deficiencies.

The quartz fiber arrays position a linear array of optical fibers on standard pitch (e.g. 250 micrometers), but the tolerances are typically greater than 1 micrometer, which is not ideal for single-mode applications.

Additionally, the quartz fiber arrays are expensive to manufacture since they are generally ground on CNC machine tools; consequently there is little cost savings with increased production volumes.

This adds another level of complication to have to adopt angled polished optical fibers having a specific angled end face that produces a mode field that matches the design angle of the grating couplers.

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