Optical waveguide array including two-dimensional lens and its manufacturing method

The optical waveguide device, comprising:

• an optical waveguide array having a plurality of waveguides, each waveguide having an incidence portion for receiving light beams and an irradiation portion for irradiating light beams, each said waveguide transmitting light beams from said incidence portion to said irradiation portion;
• first lens means for focusing the light beams irradiated from said irradiation portion in a predetermined direction substantially perpendicular to a direction of transmitting light beams through each said waveguide, said first lens means being coupled to each said waveguide;
• and
• second lens means for focusing the light beams emitted from said first lens means in a direction substantially perpendicular to both said direction of transmitting light beams and said predetermined direction, said second lens means being provided near said first lens means.

A method for manufacturing a two-dimensionally refractive index profile lens, comprising the steps of:

• providing a first clad layer, said first clad layer being planar;
• forming a core layer over said first clad layer, said core layer having a refractive index variable through photo polymerization to transmit light beams in a predetermined direction;
• irradiating light beams onto said core layer and continuously varying the irradiation energy to distribute the refractive index two-dimensionally;
• and
• coating said core layer with a second clad layer having a refractive index less than that of said core layer.

A method for manufacturing an optical waveguide array with a two-dimensionally refractive index profile lens, comprising the steps of:

• providing a first clad layer, said first clad layer being planar;
• forming a core layer including monomer over said first clad layer, said core layer having a refractive index variable through photo polymerization to transmit light beams in a predetermined direction;
• positioning a first mask over said core layer, said first mask having rectangular openings over a first portion of said core layer;
• irradiating light beams onto said masked core layer;
• removing said first mask;
• positioning a second mask over said first portion of said core layer for covering said first portion;
• positioning a third mask with wedge-shaped openings over said core layer;
• irradiating light beams onto said masked core layer while moving said third mask in a direction substantially parallel to said predetermined direction of said first portion and continuously varying the irradiation energy to distribute the refractive index two-dimensionally;
• removing said second mask;
• baking said core layer to remove unreacted monomer;
• and
• coating said core layer with a second clad layer having a refractive index less than that of said core layer.

A method for manufacturing a two-dimensionally refractive index profile lens, comprising the steps of:

• providing a glass plate containing ions;
• masking the side surfaces of said plate;
• and
• immersing said masked plate in a fused salt containing natrium or potassium ion, thereby exchanging ions in said plate with ions in the fused salt at a high temperature to provide the concentration gradient of ions for increasing the refractive index.

A method for manufacturing a two-dimensionally refractive index profile lens, comprising the steps of;

• obtaining a borosilicate glass with a phase rich in silica gel (SiO.sub.2) and a phase rich in one of sodium (Na.sub.2) and boric acid (B.sub.2 O.sub.2) by phase splitting between 500.degree. C. and 600.degree. C.;
• treating said glass with at least one selected from a group consisting of hydrogen chloride (HCl), nitric acid (HNO.sub.3) and sulfuric acid (H.sub.2 SO.sub.4) at 100.degree. C. to obtain porous glass rich in silica gel (SiO.sub.2);
• stuffing said glass with dopant of an aqueous solution of at least one of cesium nitrate (CsNO.sub.3) or thallium nitrate (TlNO.sub.3) at 100.degree. C.;
• masking the side surfaces of said glass;
• eluting the dopant from the pores in said porous glass at a temperature between 70.degree. C. and 100.degree. C.;
• and
• sintering said glass at a temperature between 700.degree. C. and 800.degree. C. to transform said glass into the lens.