PHOTOREGULATION ELEMENT AND PRODUCTION METHOD THEREOF

摘要

A photoregulation element having a single-mode waveguide in a photoregulation element having a ridge type waveguide, especially, a photoregulation element having a single-mode waveguide can be produced with precision and stability even if a substrate is a thin sheet up to 10 µm in thickness. The photoregulation element has a substrate (1) formed with a light waveguide, characterized in that the substrate is a thin sheet up to 10 µm in thickness, at least part of the light waveguide is a ridge type waveguide (21), trenches (20) up to 10 µm wide are provided at the opposite sides of at least part of the ridge type waveguide, and a tapered waveguide unit (region B) is provided that continuously change the width or depth of the trench to thereby continuously change the light propagation mode of the waveguide between a single mode and a multiple mode. Preferably, the pbotoregulation element is characterized in that the tapered waveguide unit is disposed at an incident portion or/and an outgoing portion, and a guided light at the disposed portion is a single-mode light.