Vertical cavity surface emitting laser feedback system and method

Claim 1

A feedback system for monitoring the optical radiation emitted from a vertical cavity surface emitting laser, the system comprising: an optics housing forming an internal optics cavity and having a partially reflective window disposed at a first end of the optics cavity and a header base for mounting optical components thereon and enclosing a second end of the optics cavity; a PIN photodiode mounted on the header having upper and lower surfaces; a metallic mask formed over a portion of the upper surface of the PIN photodiode, leaving a portion of the upper surface exposed; a vertical cavity surface emitting laser mounted on the mask, the mask separating the vertical cavity surface emitting laser and the PIN photodiode, and masking a portion of the upper surface of the PIN photodiode beyond an area covered by the vertical cavity surface emitting laser, the vertical cavity surface emitting laser being configured to radiate optical radiation toward the partially reflective window in the first end of the optics housing; the partially reflective window reflecting a portion of the radiation back against the exposed portion of the upper surface of the PIN photodiode, the reflected radiation generating a feedback current within the PIN photodiode proportional to the amount of radiation emitted from the vertical cavity surface emitting laser.