EYE SAFETY AND INTEROPERABILITY OF ACTIVE CABLE DEVICES

• US 20080267620A1
• Filed: 04/30/2008
• Published: 10/30/2008
• Est. Priority Date: 04/30/2007
• Status: Active Grant

• Current Assignee: II-VI Delaware, Inc. (Coherent Corp.)
• Original Assignee: Finisar Corporation (II-VI Incorporated)
• Inventors: Aronson, Lewis B., Cole, Christopher R., Douma, Darin James
• Granted Patent: US 8,526,810 B2
• Time in Patent Office: Days
• US Class Current: 398/17
• CPC Class Codes: G02B 2006/4297 having protection means, e.g. protecting humans against accidental exposure to harmful laser radiation
• CPC Class Codes: G02B 6/4284 of optical modules with disconnectable electrical connectors latching arms for electrical connectors H01R13/627
• CPC Class Codes: H04B 10/0775 Performance monitoring and measurement of transmission parameters
• CPC Class Codes: H04B 2210/08 Shut-down or eye-safety

Abstract

An integrated cable configured to communicate over much of its length using one or more optical fibers includes an electrical connector at least one end. The electrical connector at a first end of the integrated cable and an optoelectronic device coupled to or included in the other end of the integrated cable may utilize a bidirectional status link to transmit status data to each other. If the status data indicates that optical signals transmitted over the optical channels between the two devices are not potentially exposed to view, the two devices may operate above nominal eye safety limits. Otherwise, the two devices may operate at or below nominal eye safety limits. If the second optoelectronic device is not status-link enabled, the first optoelectronic device may operate at or below nominal eye safety limits.

Claims

1. In a first optoelectronic device, a method of actively maintaining eye safety while permitting operation of the first optoelectronic device above a nominal eye safety limit, the method comprising:

initiating operation in a transmit power mode in which average transmit optical power is below a nominal eye safety limit;

monitoring a status link established by a second optoelectronic device with the first optoelectronic device for status data indicative that it is safe for the first optoelectronic device to transmit one or more optical signals to the second optoelectronic device at an aggregate optical transmit power that is greater than the nominal eye safety limit;

in response to not detecting the status data, maintaining operation in the transmit power mode in which average optical power is below the nominal eye safety limit; and

in response to detecting the status data, transitioning to a transmit power mode in which the average transmit optical power is above the nominal eye safety limit.

2. The method of claim 1, wherein:

the first optoelectronic device includes;

a first opto-electrical transducer coupled to a first end of a first optical fiber external to the first optoelectronic device such that when a first optical signal is present on the first optical fiber, the first opto-electrical transducer receives the first optical signal and converts the first optical signal into a first electrical signal which is provided through a first electrical interface to a host;

a first electro-optical transducer coupled through the first electrical interface to the host and configured to receive from the host a second electrical signal, wherein when the second electrical signal is received from the host, the first electro-optical transducer converts the second electrical signal into a second optical signal and provides the second optical signal to a second optical fiber coupled to the first electro-optical transducer and external to the first optoelectronic device; and

the first optoelectronic device, the first optical fiber and the second optical fiber are integrated within a single integrated cable.

3. The method of claim 2, wherein the nominal eye safety limit includes one or more IEC Class 1 eye safety limits.

4. The method of claim 2, wherein the first electro-optical transducer, the second optical fiber, and a second opto-electrical transducer of the second optoelectronic device are included within a first optical link, the method further comprising monitoring a second optical link to determine whether one or more optical signals transmitted from the second optoelectronic device to the first optoelectronic device over the second optical link are potentially exposed to view.

5. The method of claim 4, wherein the second optical link includes a second electro-optical transducer of the second optoelectronic device, the first optical fiber and the first opto-electrical transducer, wherein the second electro-optical transducer is coupled to a second end of the first optical fiber and emits the first optical signal onto the first optical fiber.

6. The method of claim 5, wherein monitoring the second optical link to determine whether one or more optical signals transmitted from the second optoelectronic device to the first optoelectronic device over the second optical link are potentially exposed to view includes:

detecting a receiver bias current of the first opto-electrical transducer; and

comparing the receiver bias current to a threshold value.

7. The method of claim 4, further comprising, establishing a status link with the second optoelectronic device.

8. The method of claim 7, further comprising:

if the first optoelectronic device determines that one or more optical signals transmitted over the second optical link are not potentially exposed to view, transmitting to the second optoelectronic device second status data indicative that it is safe for the second optoelectronic device to transmit one or more optical signals to the first optoelectronic device at an aggregate optical transmit power that is greater than the nominal eye safety limit; and

if the first optoelectronic device determines that one or more optical signals transmitted over the second optical link are potentially exposed to view, not transmitting the second status data to the second optoelectronic device.

9. In a first optoelectronic device that is status-link enabled, a method of interoperating with a second optoelectronic device, the method comprising:

in response to a triggering event, operating in a transmit power mode in which average transmit optical power is below a nominal eye safety limit;

determining whether the second optoelectronic device is status-link enabled;

in response to determining that the second optoelectronic device is not status-link enabled, continuing to operate in the transmit power mode in which average transmit optical power is below the nominal eye safety limit; and

in response to determining that the second optoelectronic device is status-link enabled, transitioning to a transmit power mode in which average optical power is above the nominal eye safety.

10. The method of claim 9, wherein:

the first optoelectronic device includes;

a first opto-electrical transducer coupled to a first end of a first optical fiber external to the first optoelectronic device such that when a first optical signal is present on the first optical fiber, the first opto-electrical transducer receives the first optical signal and converts the first optical signal into a first electrical signal which is provided through a first electrical interface to a host;

a first electro-optical transducer coupled through the first electrical interface to the host and configured to receive from the host a second electrical signal, wherein when the second electrical signal is received from the host, the first electro-optical transducer converts the second electrical signal into a second optical signal and provides the second optical signal to a second optical fiber coupled to the first electro-optical transducer and external to the first optoelectronic device; and

the first optoelectronic device, the first optical fiber and the second optical fiber are integrated within a single integrated cable.

11. The method of claim 10, wherein a triggering event includes at least one of:

powering on the first optoelectronic device;

resetting the first optoelectronic device;

detecting a loss of signal from the second optoelectronic device;

or

detecting a fault condition.

12. The method of claim 10, wherein determining that the second optoelectronic device is not status-link enabled includes one or more of:

the second optoelectronic device not establishing a status link with the first optoelectronic device within a prescribed time after the first optoelectronic device requests that the second optoelectronic device do so using a status link established by the first optoelectronic device with the second optoelectronic device; and

the second optoelectronic device establishing a main communication link but not a status link with the first optoelectronic device.

13. The method of claim 10, wherein operation in the transmit power mode in which average transmit optical power is below the nominal eye safety limit is achieved by reducing transmit power relative to the transmit power mode in which average transmit optical power is above the nominal eye safety limit.

14. The method of claim 13, wherein reducing transmit power includes one or more of:

reducing the magnitude of a transmitter bias current for the first electro-optical transducer; and

reducing the duty cycle of the transmitter bias current.

15. The method of claim 14 wherein the total transmit power of the first optoelectronic device while operating in the transmit power mode in which average transmit optical power is below the nominal eye safety limit is set at a maximum possible value while still remaining at or slightly below the maximum eye safety limit.

16. An integrated cable comprising:

a first optical fiber within the integrated cable;

an electrical connector at a first end of the integrated cable, the electrical connector including;

a first opto-electrical transducer coupled to a first end of the first optical fiber such that when a first optical signal is present on the first optical fiber, the first opto-electrical transducer receives the first optical signal and converts the first optical signal into a first electrical signal;

a first electrical interface coupled to the first opto-electrical transducer such that when the first optical signal is received by the first opto-electrical transducer, the first electrical interface receives the first electrical signal, wherein the first electrical interface is configured to be electrically coupled to a first host receptacle external to the integrated cable such that when connected to the first host receptacle and when the first electrical signal is present on the first electrical interface, the first electrical signal is provided to the first host receptacle; and

a controller for;

establishing a status link with an optoelectronic device, wherein the status link may be used to facilitate operation above a nominal eye safety limit; and

transitioning between a transmit power mode in which average transmit optical power is below the nominal eye safety limit and a transmit power mode in which average transmit optical power is above the nominal eye safety limit.

17. An integrated cable in accordance with claim 16, wherein the first electrical connector further includes:

a first electro-optical transducer coupled to the first electrical interface such that when a second electrical signal is applied to the first electrical interface, the first electro-optical transducer receives the second electrical signal and converts the second electrical signal into a second optical signal; and

a second optical fiber coupled to the first electro-optical transducer such that when the second electrical signal is present on the first electrical interface, the second optical fiber receives the second optical signal from the first electro-optical transducer at a first end of the second optical fiber.

18. An integrated cable in accordance with claim 17, wherein:

the first electrical signal comprises a differential receive signal and the second electrical signal comprises a differential transmit signal;

the first electrical interface includes at least a first group of four electrical connectors and a second group of four electrical connectors;

the first group of four electrical connectors includes two electrical connectors configured to be coupled to ground and two electrical connectors configured to communicate the differential receive signal to a host; and

the second group of four electrical connectors includes two electrical connectors configured to be coupled to ground and two electrical connectors configured to receive the differential transmit signal from the host.

19. An integrated cable in accordance with claim 17, further comprising the optoelectronic device at a second end of the integrated cable, the optoelectronic device including:

a second opto-electrical transducer coupled to a second end of the second optical fiber such that when the second optical signal is present on the second optical fiber, the second opto-electrical transducer receives the second optical signal and converts the second optical signal into a third electrical signal;

a second electrical interface coupled to the second opto-electrical transducer such that when the second optical signal is received by the second opto-electrical transducer, the second electrical interface receives the third electrical signal, wherein the second electrical interface is configured to be electrically coupled to a second host receptacle external to the integrated cable such that when connected to the second host receptacle and when the third electrical signal is present on the second electrical interface, the third electrical signal is provided to the second host receptacle; and

a second electro-optical transducer coupled to the second electrical interface and to a second end of the first optical fiber such that when a fourth electrical signal is applied to the second electrical interface, the second electro-optical transducer receives the fourth electrical signal and converts the fourth electrical signal into the first optical signal which is received by the first optical fiber.

20. An integrated cable in accordance with claim 16, further comprising an optical connector at a second end of the integrated cable, wherein the optical connector is sized to be coupled to the optoelectronic device, the optoelectronic device comprising an optoelectronic transceiver or transponder.