Optical sensor and analyzer using the same

An optical sensor and an analyzer, comprising:

• an optical waveguide in which an insulating layer and a core layer formed on a substrate are patterned by etching to form the core layer in a spiral shape;
• a light emitting element that causes light to enter one end of the optical waveguide;
• and
• a light receiving element that receives transmitted light emitted from another end of the optical waveguide,
• wherein a cladding layer on a side opposite to the substrate with respect to the core layer is removed or thinned,
• wherein optical transmittance in the optical waveguide is measured based on a ratio of intensity of the light emitted from the light emitting element to intensity of the light received by the light receiving element,
• wherein a semiconductor laser is integrated into the optical waveguide as the light emitting element, the semiconductor laser being formed of a compound semiconductor attached to an upper surface of the optical waveguide substrate, the semiconductor laser being of a ridge type,
• wherein the semiconductor laser includes a first InP layer and a second InP layer disposed above the first InP layer,
• wherein the semiconductor laser includes electrodes disposed on the first InP layer,
• wherein the second InP layer is disposed between the electrodes in a plan view,
• wherein distribution of propagating light is moved from the semiconductor laser to the optical waveguide by a reduction in an effective refractive index of layers of the compound semiconductor forming the semiconductor laser in a direction of light propagation,
• wherein a width of the second InP layer decreases in the direction of light propagation, and
• wherein a width of the first InP layer of the layers of the compound semiconductor forming the semiconductor laser is shaped in a manner to form multiple tapered portions.