Method for assembling optical module and optical module

摘要

A method to determine a position of a lens that concentrates an optical beam on an inclined end surface of an optical fiber is disclosed. The method first determines two positions at which optical power output from the lens and measured through a multi-mode fiber becomes a maximum on respective virtual plane apart from the lens; then, calculates the direction or the angle of the optical beam output from the lens, and moves the lens so as to compensate a deviation of the calculated direction from the designed direction.

主权项

1. A method of assembling a lens against a semiconductor laser diode (LD) that emits an optical beam, the lens concentrating the optical beam onto an inclined end surface of an optical fiber, the method comprising steps of:
replacing the optical fiber with a multi-mode fiber (MMF); determining a first point on a first virtual plane as varying a relative position between the MMF and the lens, at which optical power measured through the MMF becomes a maximum, the first virtual plane extending perpendicular to an optical axis of the lens and being apart from the lens by a first distance; determining a second point on a second virtual plane as varying a relative position between the MMF and the lens, at which optical power measured through the MMF becomes another maximum, the second virtual plane extending perpendicular to the optical axis of the lens and being apart from the lens by a second distance different from the first distance; calculating a direction of the optical beam output from the lens based on the first point and the second point; and moving the lens relative to the LD such that the calculated direction of the optical beam output from the lens is within a preset range around a designed direction, wherein the steps of determining the first point and the second point include steps of: on the first virtual plane and the second virtual plane, obtaining initial points at which the optical power measured through the MMF becomes respective maxima as varying the relative positions between the MMF and the lens along a first direction; obtaining subsequent points at which the optical power measured through the MMF becomes other respective maxima as varying relative positions between the MMF and the lens along a second direction perpendicular to the first direction from the respective initial points; and setting the subsequent point obtained in the first virtual plane as the first point and the subsequent point obtained in the second virtual plane as the second point.