Apparatus and method of signal detection in an optical transceiver

• US 20090016731A1
• Filed: 02/09/2007
• Published: 01/15/2009
• Est. Priority Date: 11/18/2003
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Pharn, Art, Vafiades, Todd
• Granted Patent: US 7,976,225 B2
• Time in Patent Office: Days
• US Class Current: 398/137
• CPC Class Codes: H04B 10/40 Transceivers

Abstract

The present invention includes an optical transceiver having a fiber module with an optical data input and an electrical data output. The fiber module further includes a signal detect output that indicates the receipt of valid optical data. A physical layer device having a receive input is coupled to the electrical data output through a switch that is controlled by the signal detect output. The switch passes electrical data from the electrical data output of the fiber module to the receive input when the signal detect output indicates the receipt of valid optical data, and does not pass the electrical data when the signal detect output indicates invalid optical data. By using this configuration, the signal detects pins of the physical layer device are eliminated. In another embodiment, the switch is not utilized, and the electrical data output of the transceiver is ac-coupled to the differential receive input of the physical layer device. In this embodiment, the transceiver does not output electrical data when the optical data signal is invalid. Therefore, electrical data is identified at the receive input by the detection of a voltage variation on the differential receive input.

Claims

1. An optical transceiver, comprising:

a fiber module having an optical data input and an electrical data output; and

a physical layer device having a receive input that is coupled to said electrical data output;

wherein said fiber module is configured to;

(1) determine validity of optical data signal received at said optical data input, and (2) generate an electrical data signal at said electrical data output that is representative of an optical data signal only when said optical data signal is valid;

wherein said physical layer device identifies a valid data input based on a voltage variation of an electrical signal received at said receive input and does not utilize a signal detect signal from said fiber module.

2. The optical transceiver of claim 1, wherein said fiber module is an Agilent HRZBR 5903.

3. The optical transceiver of claim 1, wherein said fiber module is configured to generate said electrical data signal at said electrical data output when said optical data signal has an amplitude that is above a threshold.

4. The optical transceiver of claim 1, further comprising a first bias network connected to said receive input of said physical layer device, and a second bias network connected to said electrical data output of said fiber module.

5. The optical transceiver of claim 1, wherein said physical layer device identifies a valid data input based on a voltage variation of an electrical signal received at said receive input.

6. In an optical transceiver having a physical layer device and a fiber module, said transceiver receiving an optical data signal and converting said optical data signal to an electrical signal, said transceiver further having a signal detect output that indicates validity of said optical data signal, a method comprising:

receiving an optical data signal;

determining if said optical data signal is a valid optical data signal;

if said optical data signal is valid, then converting said optical data signal to an electrical data signal;

sending said electrical data signal to a physical layer device; and

accepting the electrical data signal as a valid electrical data signal at the physical layer device based on a voltage variation of the electrical data signal without using a signal detect signal from the fiber module.

7. The method of claim 6, wherein said step of determining includes determining if said optical data signal exceeds an amplitude threshold.