A new low-cost, highly reliable and compact optical power monitor is manufactured
with simplified structure and improved configurations that require only lateral
position adjustment for input/output beam alignment. A compact size is achieved
by employing prefabricated housing containing a highly effective focus lens placed
at fixed position relative to an optical sensor, e.g., a photodiode. The prefabricated
housing further function as a seal housing for direct plugging into a holding tube
fitting seamlessly to a GRIN lens to focus the tapped collimated beam to the photo
sensor thus greatly simplify the manufacturing processes without alignment requirements.
Thermal stability and reliable performance is achieved by applying multiple-layered
optical reflection-transmission coating directly onto the end surface of a GRIN
lens for tapping a small portion of the collimated beam onto the focus lens and
the photo sensor. The insertion loss can be conveniently minimized by laterally
shifting the relative position of a dual fiber ferrule and the GRIN lens without
complicate angular adjustments. A power monitor with compact size, high damage
threshold, low manufacture cost and high performance stability is provided for
convenient implementation in new and existing optical systems.
