Apparatus for coupling laser and optical fiber, and optical signal transmission system and transmission method

An optical signal transmission system, comprising:

• a laser;
• an optical fiber;
• and
• an apparatus for coupling the laser and the optical fiber,
• wherein the apparatus comprises a laser fixing part, an optical fiber fixing part, and an optical signal transmission part,
• wherein the laser is coupled with the apparatus using the laser fixing part,
• wherein the optical fiber is coupled with the apparatus using the optical fiber fixing part,
• wherein the optical signal transmission part comprises two ends,
• wherein the laser fixing part and the optical fiber fixing part are respectively disposed at the two ends of the optical signal transmission part,
• wherein a refractive index of the optical signal transmission part changes gradually,
• wherein the refractive index of the optical signal transmission part becomes higher at a position closer to a principal axis to output an optical signal incident from the laser coupled to the laser fixing part, and then emit the optical signal into the optical fiber,
• wherein the optical signal transmission part comprises a first subpart and a second subpart,
• wherein the first subpart is in a shape of a circular truncated cone,
• wherein the second subpart wraps around the first subpart,
• wherein a cross-sectional radius of the first subpart changes gradually,
• wherein a refractive index becomes higher at a position closer to a center in any cross-section, and
• wherein a refractive index of the second subpart is constant.

A method for performing optical signal transmission, comprising:

• emitting, into a coupling apparatus, an optical signal emitted from a laser coupled with an apparatus for coupling a laser and an optical fiber;
• performing optical signal convergence or divergence when the optical signal is transferred within an optical signal transmission part of the coupling apparatus, wherein a refractive index of the optical signal transmission part changes gradually;
• and
• emitting, from the coupling apparatus, a converged optical signal or diverged optical signals into the optical fiber coupled by the coupling apparatus,
• wherein the optical signal transmission part comprises a first subpart and a second subpart,
• wherein the first subpart is in a shape of a circular truncated cone,
• wherein the second subpart wraps around the first subpart,
• wherein a cross-sectional radius of the first subpart changes gradually,
• wherein a refractive index becomes higher at a position closer to a center in any cross-section, and
• wherein a refractive index of the second subpart is constant.