Integrated optical tap monitor
An integrated optical tap monitor takes the form of a highly-reflective outer coating disposed over the active region of an associated photodetector. The coating is of a material that allows for a majority of the impinging optical signal to be re-directed into an output path, while passing a small portion of the signal into the photodetector's active region for monitoring purposes. The integrated configuration is small enough to be housed within a standard TO can, and additional optical components (filters, attenuators, etc.) may be co-located with the integrated tap monitor. By virtue of incorporating the monitoring function with a reflective surface, the integrated tap monitor may be substituted for a turning mirror at any place along a signal path and provide the benefit of power monitoring while also performing signal re-direction.
1. An optical tap monitor comprising:
a photodetector including an active region for converting a received optical signal into an electrical equivalent thereof; and
a high reflectivity coating disposed on an outer surface of the photodetector to create an HR-coated photodetector, the high reflectivity coating configured to reflect a majority of a propagating optical signal impinging the surface thereof, and pass a remaining portion of the propagating optical signal into the active region of the photodetector for conversion into an electrical monitoring signal, the reflected majority of the propagating optical signal forms an optical output signal of the optical tap monitor.
2. The optical tap monitor as defined in claim 1 , further comprising
a housing for enclosing the HR-coated photodetector, the housing including electrical anode and cathode pin connections to the HR-coated photodetector.
3. The optical tap monitor as defined in claim 2 wherein an optical element is disposed within the housing and positioned in optical alignment with the HR-coated photodetector.
4. The optical tap monitor as defined in claim 2 wherein the optical element comprises a tunable optical filter.
5. The optical tap monitor as defined in claim 1 wherein the high reflectivity coating is disposed to cover a surface area of the photodetector that at least matches a beam width of the propagating optical signal.
6. The optical tap monitor as defined in claim 1 wherein the high reflectivity coating is formed of one or more materials selected to provide transmission and reflection for a wide wavelength range.
7. The optical tap monitor as defined in claim 1 wherein the high reflectivity coating is formed of one or more materials selected to restrict transmission and reflection to a predetermined wavelength range.
8. The optical tap monitor as defined in claim 1 , further comprising
a dual fiber collimator disposed in optical alignment with the HR-coated photodetector, the dual fiber collimator including an input fiber, an output fiber, and collimating optics, with the input and output fibers coupled to a first end of the collimating optics and a second, opposing end of the collimating optics disposed to be in optical communication with the high reflectivity coating of the optical tap monitor, such that an optical signal propagating along the input fiber is collimated and thereafter impinges the high reflectivity coating, reflecting a majority of the optical signal back through the collimating optics and into the output fiber and forwarding a portion of the optical signal into the photodetector to be monitored.
9. The optical tap monitor as defined in claim 8 , further comprising an optical element disposed in the optical signal path between the collimating optics and the high reflectivity coating.
10. The optical tap monitor as defined in claim 9 , wherein the optical element and the HR-coated photodetector are contained within a housing, and the dual fiber collimator is aligned with and connected to the housing.
11. The optical tap monitor as defined in claim 10 wherein the optical element comprises a tunable optical filter.
12. The optical tap monitor as defined in claim 1 , wherein the high reflectivity coating is selected from the group consisting of: tungsten, aluminum, copper, zinc, gold, silver, titanium, tantalum, chromium, tin, cobalt, nickel, or any alloys of these materials.
13. The optical tap monitor as defined in claim 1 , wherein the optical tap monitor functions as a turning mirror, also providing monitoring functions.
14. The optical tap monitor as defined in claim 1 wherein the photodetector is utilized to monitor modulated optical signals.
15. An integrated optical component comprising
a broad area photodetector including an active region for converting a received optical signal into an electrical equivalent thereof; and
a high reflectivity coating disposed on an outer surface of the photodetector to create an HR-coated photodetector, the high reflectivity coating forming a turning mirror to reflect a majority of an incoming optical signal, wherein
the high reflectivity coating is further configured to pass a portion of the incoming optical signal into the active region of the broad area photodetector for use as an optical monitor signal.
16. An optical tap monitor comprising:
a high-speed photodetector including an active region for converting a received optical signal into an electrical equivalent thereof; and
a high reflectivity coating disposed on an outer surface of the high-speed photodetector to create an HR-coated photodetector, the high reflectivity coating configured to reflect a majority of a propagating optical signal impinging the surface thereof, and pass a remaining portion of the propagating optical signal into the active region of the high-speed photodetector for conversion into an electrical monitoring signal, the reflected majority of the propagating optical signal forming an optical output signal of the optical tap monitor.
17. An optical tap monitor as defined in claim 16 wherein the propagating optical signal exhibits a predetermined beam size compatible with the active region of the high-speed photodetector and the high reflectivity coating is formed to cover a surface area of the high-speed photodetector that is at least substantially the same as the optical signal beam size.