Compact fiber coupler and method of manufacturing the same

A method of manufacturing a compact fiber coupler, comprising the steps of:

• (i) forming a V-groove with a radius curvature R on a semiconductor substrate;
• (ii) positioning glue at both sides of the V-groove, and absorbing the glue from both sides of the V-groove by capillarity;
• (iii) fixing a first optical fiber in the V-groove;
• (iv) forming a first side-polished region by polishing the cladding of the first optical fiber, wherein the core of the first optical fiber is near the first side-polished region;
• (v) isolating the first optical fiber from the semiconductor substrate using a liquid;
• (vi) forming a second optical fiber with a second side-polished region by repeating the steps of (i) to (v);
• and
• (vii) creating the compact fiber coupler by aligning and fusing the first side-polished region and the second side-polished region together, wherein a coupling region is formed between the first side-polished region and the second side-polished region.