Laser drivers for closed path optical cables

• US 7,860,398 B2
• Filed: 09/06/2006
• Issued: 12/28/2010
• Est. Priority Date: 09/15/2005
• Status: Expired due to Fees

• Current Assignee: II-VI Delaware, Inc. (Coherent Corp.)
• Original Assignee: Finisar Corporation (II-VI Incorporated)
• Inventors: Guenter, James K., Tatum, Jimmy A.
• Primary Examiner(s): Bello; Agustin
• Application Number:
  US11/470,623
• Publication Number:
  US 20070058976A1
• Time in Patent Office: 1,574 Days
• Field of Search: 398140-141, 398182-201
• US Class Current: 398/141
• CPC Class Codes: G02B 6/4201 Packages, e.g. shape, construction, internal or external details
• CPC Class Codes: G02B 6/4246 Bidirectionally operating package structures
• CPC Class Codes: G09G 2370/12 Use of DVI or HDMI protocol in interfaces along the display data pipeline
• CPC Class Codes: G09G 2370/18 Use of optical transmission of display information
• CPC Class Codes: G09G 5/006 Details of the interface to the display terminal specific for a display terminal using a CRT G09G1/167; using a flat panel G09G3/2096; circuits for interfacing with colour displays G09G5/04
• CPC Class Codes: H01S 5/005 Optical components external to the laser cavity, specially adapted therefor, e.g. for homogenisation or merging of the beams or for manipulating laser pulses, e.g. pulse shaping H01S5/026, H01S5/18388 take precedence
• CPC Class Codes: H01S 5/02 Structural details or components not essential to laser action
• CPC Class Codes: H01S 5/02212 Can-type, e.g. TO-CAN housings with emission along or parallel to symmetry axis
• CPC Class Codes: H01S 5/0262 Photo-diodes, e.g. transceiver devices, bidirectional devices H01S5/0265 takes precedence
• CPC Class Codes: H01S 5/04257 having positive and negative electrodes on the same side of the substrate
• CPC Class Codes: H01S 5/18313 by oxidizing at least one of the DBR layers
• CPC Class Codes: H01S 5/3095 Tunnel junction
• CPC Class Codes: H04B 10/801 using optical interconnects, e.g. light coupled isolators, circuit board interconnections
• CPC Class Codes: H04J 14/08 Time-division multiplex systems

Abstract

Simplified laser drivers for closed path digital optical cables and digital optical cables including the simplified laser drivers. The laser driver can include less transistors than conventional laser drivers for optical communication cables. The laser can include a bias source and modulation source. The bias source can have a single constant current bias point for all laser diodes. The modulation current source can have a single temperature coefficient for all laser diodes. The laser driver can exclude, for example, any one of or combination of temperature compensation of the modulation or bias current sources, external programming of the modulation or bias current sources, power control based on output of the laser diode, and/or control based on feedback received from a monitor device or other sensor within the cables.

Claims

1. A closed path digital optical cable comprising:

an optical fiber having a first end and a second end;

a first interface configured to couple the closed path digital optical cable to a digital source device, the first interface comprising;

an optical transmitter circuit configured to receive an electronic DVI or HDMI signal from the digital source device, the DVI or HDMI signal including electronic R, G, and B TMDS video signals, the optical transmitter circuit further configured to convert the electronic signal including the R, G, and B signals to one or more optical signal, and transmit the one or more optical signal onto the first end of the optical fiber;

a laser driver circuit configured to provide a drive current to the optical transmitter, the laser driver circuit comprising a modulation current source with only one modulation point and only one temperature coefficient thereby excluding temperature compensation; and

a second interface configured to couple the closed path digital optical cable to a digital sink device, the second interface comprising;

an optical receiver configured to receive the one or more optical signal from the second end of the optical fiber, convert the one or more optical signal to a DVI or HDMI electronic signal including the R, G, and B electronic signals, and transmit the DVI or HDMI electronic signal to the digital sink device, wherein the first interface and the second interface are interconnected with the optical fiber so as to form a closed optical path.

2. A closed path digital optical cable according to claim 1, wherein the laser driver circuit further comprises a bias current source with only one bias current point.

3. A closed path digital optical cable according to claim 1, wherein the laser driver has only one capacitor and only one inductor.

4. A closed path digital optical cable according to claim 1, wherein the first interface is configured to electrically connect to a digital video interface (DVI) receptacle of the digital source device or a high definition multimedia (HDMI) receptacle of the digital source device, and wherein the second interface is configured to electrically connect to a DVI receptacle of the digital sink device or a HDMI receptacle of the digital sink device.

5. A closed path digital optical cable according to claim 1, wherein the electronic signal received from the digital source device includes both video and audio electronic signals, the video signals being transmitted over the optical fiber and the audio signals being transmitted over the electrical link.

6. A closed path digital optical cable according to claim 1, wherein the first interface comprises:

a plurality of optical transmitters configured to convert electrical TMDS signals to a plurality of optical signals of different wavelengths; and

a wavelength division multiplexer (WDM) configured to receive the optical signals of different wavelengths, multiplex the optical signals into a multiplexed optical signal, and couple the multiplexed optical signal onto to the first end of the optical fiber.

7. A closed path digital optical cable according to claim 1, wherein the first interface includes a time division multiplexer (TDM) configured to multiplex signals received from the digital source device in time prior to transmission of the signals by the optical transmitter, and wherein the second interface includes a time division demultiplexer (TDD) configured to demultiplex the signals received by the optical receiver in time.

8. A closed path digital optical cable according to claim 1, wherein the electrical signal is one of a plurality of TMDS signals, and wherein the first interface further comprises:

circuitry configured to serialize the electrical TMDS signals received from the digital source device into an electrical serialized signal, wherein the optical transmitter converts the electrical serialized TDMS signal into the optical signal, and transmits the optical signal onto the first end of the optical fiber; and

wherein the optical receiver of the second interface receives the optical signal and converts the optical signal into an electrical serialized signal, the second interface further comprising;

a deserializer including circuitry configured to deserialize the electrical serialized data signal back into the TMDS signals.

9. A closed path digital optical cable according to claim 1, wherein the transmitter is a vertical cavity surface emitting laser (VCSEL) for transmitting the optical signal onto the first end of the optical fiber in a first direction;

wherein the second interface includes a light emitting diode (LED) for transmitting a second optical signal onto the second end of the optical fiber in a second direction, wherein the second direction is opposite to the first direction; and

wherein the first interface further includes a receiver for receiving the second optical signal transmitted in the second direction by the LED.

10. A closed path digital optical cable according to claim 1, wherein at least one of the first interface and/or the second interface comprises:

a VCSEL; and

a TO-Can package encasing the VCSEL, a monitor optical receiver, and the modulation current source.

11. A closed path digital optical cable according to claim 1, wherein the first interface further comprises:

a serializer including circuitry configured to serialize a plurality of TMDS signals into an electrical serialized signal;

a first transmit optical subassembly (TOSA) configured to convert the electrical serialized signal into an optical serialized signal, and transmit the optical serialized signal onto the first end of the optical fiber;

a first receive optical subassembly (ROSA) configured to receive a return optical signal from the optical fiber; and

wherein the second interface further comprises;

a second ROSA configured to receive the optical serialized signal, and convert the optical serialized signal into an electrical serialized signal;

a second deserializer including circuitry configured to deserialize the electrical serialized signal into TDMS signals; and

a second TOSA configured to transmit the return optical signal to the optical fiber.

12. A closed path digital optical cable according to claim 1, wherein at least one of the first interface and/or the second interface comprises an optoelectronic device for detecting an incoming light beam along a light beam axis and for transmitting an outgoing light beam along the light beam axis, the optoelectronic device comprising:

an optical detector positioned along the light beam axis for receiving the incoming light beam and for detecting a first wavelength and/or range of wavelengths; and

the optical transmitter positioned along the light beam axis for transmitting the outgoing light beam, wherein the outgoing light beam includes a second wavelength and/or range of wavelengths.

13. A closed path digital optical cable according to claim 1, wherein at least one of the first interface and/or the second interface comprises an optoelectronic device comprising:

a transmitter diode comprising a first p-n junction with a first p-layer and a first n-layer;

a first tunnel junction coupled monolithically to the transmitter diode, the tunnel junction comprising a heavily doped n+ layer and a heavily doped p+ layer; and

a first photodiode coupled monolithically to the first tunnel junction, the first tunnel junction comprising a second p-n junction.

14. A closed path digital optical cable according to claim 1, wherein at least one of the first interface and/or the second interface comprises a bidirectional optical device comprising:

an optical port;

a wavelength splitter proximate to the optical port;

a light source proximate to the wavelength splitter; and

a detector proximate to the wavelength splitter; and

wherein;

the wavelength splitter passes light having a first wavelength from the light source to the optical port; and

the wavelength splitter reflects light having a second wavelength from the optical port to the detector.

15. A digital optical cable according to claim 1, wherein the optical fiber is also used to transfer one or more control signal over the optical fiber fro controlling the operation of the digital source device or digital sink device, the control signal including a DDC signal.

16. A digital optical cable according to claim 1, wherein the optical fiber is also used to transfer one or more control signal over the optical fiber fro controlling the operation of the digital source device or digital sink device, the control signal including a CEC signal.

17. A digital optical cable according to claim 1, wherein the optical fiber is also used to transfer one or more control signal over the optical fiber fro controlling the operation of the digital source device or digital sink device, the control signal including an EDID signal.

18. A digital optical cable according to claim 1, wherein the optical fiber is also used to transfer one or more control signal over the optical fiber fro controlling the operation of the digital source device or digital sink device, the control signal including an EDID, CEC, and DDC signal.

19. A digital optical cable comprising:

a single optical fiber having a first end and a second end;

a first interface configured to couple the digital optical cable to a first digital consumer electronic device, the first interface comprising;

first electrical connections configured to receive electrical TMDS signals including R, G, and B signals from a receptacle of the first digital consumer electronic device; and

a laser configured to convert at least one of the TMDS signals to an outgoing optical signal and for transmitting the outgoing optical signal onto the first end of the single optical fiber such that the R, G, and B signals are transmitted over the single optical fiber;

a laser driver including a single capacitor and a single inductor and configured to provide a drive current to the optical transmitter without temperature compensation; and

a second interface configured to couple the digital optical cable to a second digital consumer electronic device and comprising;

an optical receiver for receiving the outgoing optical signal and for converting the outgoing optical signal back into the at least one of the TMDS signals including the R, G, and B signals; and

second electrical connections configured to transmit the electrical TMDS signals to a receptacle of the second digital electronic consumer device, the digital optical cable being configured to enable bidirectional communication between the first and second digital communication devices including communication of control communication for controlling the digital source or sink device over the single optical fiber.

20. A digital optical cable according to claim 19, wherein the control communication includes a CEC signal.

21. A digital optical cable according to claim 19, wherein the control communication includes an EDID signal.

22. A digital optical cable according to claim 19, wherein the control communication includes an EDID, CEC, and DDC signal.

23. A digital optical cable according to claim 19, further comprising a serializing circuit in the first interface and a deserializing circuit in the second interface, wherein the R, B, and G signals are serialized by the serializing circuit prior to being converted to an optical signal and transmitted over the single optical fiber and deserialized back into the separate R, B, and G signals after being transmitted over the single optical fiber and converted to an electrical serialized signal.

24. A digital optical cable according to claim 19, wherein the first and second interfaces and the single optical fiber form a single closed loop optical cable such that the first and second interfaces are permanently attached to the ends of the single optical fiber.