Methods, systems and apparatus for measuring average received optical power

• US 7,002,131 B1
• Filed: 02/13/2003
• Issued: 02/21/2006
• Est. Priority Date: 01/24/2003
• Status: Active Grant

• Current Assignee: Lumentum Operations, LLC (Lumentum Holdings Inc.)
• Original Assignee: Viavi Solutions, Inc. (Lumentum Holdings Inc.)
• Inventors: Lewis, David K.
• Primary Examiner(s): Allen, Stephone B.
• Application Number:
  US10/367,501
• Time in Patent Office: 1,104 Days
• Field of Search: 250/214.A, 250/227.11, 250/205, 330/59, 330/308, 398/118, 398/141, 398/142, 398/158, 398135-136, 398/160, 398/202, 398209-210, 398/214
• US Class Current: 250/214.00A
• CPC Class Codes: H04B 10/66 Non-coherent receivers, e.g. using direct detection

Abstract

Methods, systems and apparatus for measuring average received optical power by an optical receiver. A TO-package for a packaged optical receiver is disclosed having a pin-out configuration for facilitating the direct measurement of the level of photo current induced into an optical receiver. A method and system are disclosed which include the packaged optical receiver for measuring the average received optical power by an optical receiver.

Claims

1. An optical system to receive a modulated light signal, the optical system comprising:

a photodetector to receive at least a portion of the modulated light signal and generate an electrical signal in response thereto, the electrical signal including a data signal utilized to generate the modulated light signal;

an amplifier coupled to the photodetector to receive the electrical signal, the amplifier to detect the data signal in the electrical signal; and

an optical power measuring circuit coupled to the photodetector to receive the electrical signal, responsive to the electrical signal the optical power measuring circuit to detect an average optical power level for the modulated light signal.

2. The optical system of claim 1, wherein the optical power measuring circuit has an input directly coupled to a terminal of the photodetector to receive the electrical signal.

3. The optical system of claim 1, wherein the amplifier has an input directly coupled to a terminal of the photodetector to receive the electrical signal.

4. The optical system of claim 1, wherein the electrical signal is a current signal.

5. The optical system of claim 1, wherein the electrical signal is a voltage signal.

6. The optical system of claim 1, wherein the photodetector receives a portion of the modulated light signal due to optical inefficiencies.

7. The optical system of claim 1, wherein the photodetector is a semiconductor photodiode.

8. The optical system of claim 1, wherein the modulated light signals are received from an optical waveguide.

9. The optical system of claim 8, wherein the optical waveguide is an optical fiber.

10. The optical system of claim 1, wherein the modulated light signals are received from free space.

11. An optical system to measure average received optical power in received light signals, the optical system comprising;

an optical receiver including

a device package with a header, a first pin extending into the device package through the header, and

a photodetector supported by the device package to receive the received light signals, the photodetector having a first terminal and a second terminal, the first terminal of the photodetector coupled to the first pin of the device package, the photodetector to generate an electrical signal on the first pin in response to the received light signals; and

an averaging circuit coupled to the first pin of the device package of the optical receiver, the averaging circuit to monitor the electrical signal on the first pin to determine the average received optical power in the received light signals.

12. The optical system of claim 11, wherein the device package is a TO type package, and wherein the device package has a windowed TO can coupled to the header, the windowed TO can including a window to allow passage of the received light signals into the device package.

13. The optical system of claim 11, wherein the optical receiver further includes a capacitor having a first terminal coupled to the header of the package and a second terminal coupled to the first pin, the capacitor to filter noise from the first pin.

14. The optical system of claim 13, wherein the optical receiver further includes an amplifier having an input coupled to the second terminal of the semiconductor photodetector and an output coupled to a data pin, the amplifier to amplify the photocurrent of the semiconductor photodetector and detect data signals therein to generate a data output signal on the data pin.

15. The optical system of claim 11, wherein the averaging circuit is a part of a monitoring circuit for a fiber optic module, optical transceiver, or optical data link.

16. The optical system of claim 11, wherein the received light signals are received from an optical waveguide and coupled into the device package.

17. The optical system of claim 16, wherein the optical waveguide is an optical fiber.

18. The optical system of claim 11, wherein the received light signals are received from free space and coupled into the device package.

19. The optical system of claim 11, wherein the device package has a windowed cover coupled to the header, the windowed cover including a window to allow passage of the received light signals into the device package.

20. The optical system of claim 19, wherein the window is a lens to focus light into the photodetector.

21. The optical system of claim 19, wherein the window is transmissive to desired wavelengths of the received light signals.

22. The optical system of claim 21, wherein the window is opaque to undesired wavelengths of the received light signals.

23. A method of measuring average received optical power, the method comprising:

receiving light signals;

transducing the light signals into electrical signals;

coupling the electrical signals into an averaging circuit to determine the average received optical power; and

amplifying the electrical signals into amplified electrical signals to extract data signals.

24. The method of claim 23, wherein the receiving, the transducing, and the amplifying are performed in a packaged optical receiver and the averaging circuit is external to the packaged optical receiver.

25. The method of claim 23, further comprising:

extracting data signals from the amplified electrical signals to determine the information contained therein.

26. The method of claim 25, wherein the receiving, the transducing, the amplifying, and the extracting are performed in a packaged optical receiver and the averaging circuit is external to the packaged optical receiver.

27. The method of claim 26, wherein

the receiving of light signals is performed by a device package of the packaged optical receiver,

the transducing of the light signals into the electrical signals is performed by a photodetector,

the coupling of the electrical signals into the averaging circuit to determine the average received optical power is performed by electrically connecting a terminal of the photodetector within the device package to the averaging circuit outside of the device package, and

the extracting of data signals is performed by a pre-amplifier mounted within the packaged optical receiver electrically coupled to the photodetector.

28. An optical system comprising;

a printed circuit board including an averaging circuit and a connection for connecting to a host system;

a packaged optical receiver coupled to the printed circuit board, the packaged optical receiver including a photodetector and an amplifier mounted therein, the photodetector to receive and convert optical signals into electrical signals, the amplifier to amplify the electrical signals and detect data signals therein, the packaged optical receiver directly coupling the electrical signals of the photodetector to the averaging circuit; and

a fiber optic plug receptacle to align the optical signals into the packaged optical receiver;

wherein the averaging circuit is for receiving the electrical signals from the photodetector and generating an output representing the average received optical power of the packaged optical receiver.

29. The optical system of claim 28, wherein the averaging circuit is a part of a monitoring circuit of the printed circuit board for the optical system to monitor the operational status thereof.

30. The optical system of claim 28, further comprising a housing to house the printed circuit board, the packaged optical receiver and the fiber optic plug receptacle together as a unit.

31. An optical system to receive light signals, the optical system comprising:

a TO device package including

a TO header,

at least five pins, four of the at least five pins extending into the device package and one pin of the at least five pins being a ground pin coupled to the TO header, and

a windowed TO can coupled to the header, the windowed TO can including an opening and a window coupled over the opening, the opening and the window to allow passage of the light signals into the TO device package; and

a photodetector supported by the TO header, the photodetector having a first terminal and a second terminal, the first terminal of the photodetector coupled to one of the four pins extending through the header of the TO device package, the photodetector to generate an electrical signal on the pin coupled to the first terminal in response to the light signals in order to measure the received optical power.

32. The optical system of claim 31, further comprising;

a preamplifier supported by the TO header, the preamplifier having an input coupled to the second terminal of the photodetector, the preamplifier to amplify the electrical signal and detect a data signal therein.

33. The optical system of claim 32, further comprising:

a first capacitor having a bottom terminal coupled to the To header and a top terminal coupled to the first terminal of the photodetector, the first capacitor to filter noise on the first terminal.

34. The optical system of claim 33, further comprising:

a second capacitor having a bottom terminal coupled to the TO header and a top terminal coupled to a positive power supply pin of the four pins extending through the header, the second capacitor to stabilize a level of a positive power supply provided on the positive power supply pin and filter noise therefrom.

35. The optical system of claim 33, further comprising;

a sense resistor having a first terminal coupled to a positive power supply pin of the four pins extending through the header and a second terminal coupled to the first terminal of the photodetector, the sense resistor to further generate the electrical signal to measure the received optical power level.

36. The optical system of claim 35, wherein the electrical signal is a voltage signal between the positive power supply pin and the first terminal of the photodetector.

37. The optical system of claim 31, wherein the electrical signal is a current signal on the pin coupled to the first terminal of the photodetector.

38. The optical system of claim 31, wherein the light signals are received from free space and coupled into the TO device package through the window.

39. The optical system of claim 31, wherein the light signals are received from an optical waveguide and coupled into the TO device package through the window.

40. The optical system of claim 39, wherein the optical waveguide is an optical fiber.