Improved self-mix module utilizing filters

Abstract

A system and method for generating, enhancing, and detecting the amplitude and phase modulation of a laser under a condition of self-mixing is provided. The system may comprise a laser and a detector to extract the characteristic self-mix signal, which is then interpreted using algorithms implemented in hardware or software. In the case of the laser being a Vertical Cavity Surface Emitting laser (VCSEL), the output signal can be detected by monitoring the surface light emission by means of a beam splitter, or in some embodiments as emission from the bottom surface of the laser. In some embodiments, the system may further comprise a wavelength filter such as an etalon in the signal path.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of and priority from U.S. Prov. Pat. Appl. No. 62 / 349,123, titled “Improved Self-Mix Module Utilizing Filters,” filed Jun. 13, 2016, the contents of which are hereby incorporated by reference herein in their entirety.FIELD OF THE INVENTION[0002]The present invention disclosure is related to processing of signals and to sensors based on the mechanism of laser self-mixing. Also disclosed are means for improved packaging for the sensors.BACKGROUND OF THE INVENTION[0003]The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.[0004]Self-mixing, or optical feedbac...

AI Technical Summary

Benefits of technology

The present patent is about improving self-mixing sensors by using a filter, particularly a Fabry-Perot filter, to enhance the output signal from a self-mixing device. The use of a wavelength filter can amplify the output signal from a self-mixing sensor that is sensitive to wavelength changes. The patent also discusses the use of vertical-cavity lasers and the integration of filters with etalons to enable smaller and more cost-effective sensors. Additionally, the patent describes the use of a substrate-emitting VCSEL laser and the removal of the need for a separate beam splitter. The technical effects of the patent include improved sensitivity, reduced size and complexity, and improved performance.

Problems solved by technology

However, VCSELs suffer from many of the same limitations as traditional lasers, namely the low achievable signal levels.

Work has been done to optimize VCSELs for improving VCSEL self-mixing performance, but the degree of improvement is still not adequate for a number of interesting consumer applications envisioned here.

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