OPTICAL TRANSCEIVER MODULE HAVING AN ACTIVE LINEAR OPTOELECTRONIC DEVICE

• US 20080031629A1
• Filed: 01/23/2007
• Published: 02/07/2008
• Est. Priority Date: 08/04/2006
• Status: Active Grant

• Current Assignee: II-VI Delaware, Inc. (Coherent Corp.)
• Original Assignee: Finisar Corporation (II-VI Incorporated)
• Inventors: Kamath, Kishore, Douma, Darin J., Nguyen, The-Linh, Williams, Andrew R.
• Granted Patent: US 7,734,184 B2
• Time in Patent Office: Days
• US Class Current: 398/135
• CPC Class Codes: H04B 10/40 Transceivers

Abstract

An optoelectronic transceiver comprises an active linear TOSA circuit mounted on a header. The active linear TOSA circuit includes input nodes for receiving a differential signal pair, a first bipolar transistor, a second bipolar transistor and an electro-optical transducer. A base terminal of the first bipolar transistor is coupled to the two input nodes and an emitter terminal of the first bipolar transistor is coupled to a base terminal of the second bipolar transistor. A collector terminal of the first bipolar transistor is coupled to a first terminal of the electro-optical transducer, the first terminal of the electro-optical transducer also being configured to be coupled to a voltage source. A collector terminal of the second bipolar transistor is coupled to a second terminal of the electro-optical transducer and an emitter terminal of the second bipolar transistor is coupled to a signal ground which is not the header ground.

Claims

1. An optoelectronic transceiver for use in optical communication networks, comprising:

a printed circuit board;

a receiver optical subassembly; and

an active linear transmitter optical subassembly, including;

a header grounded to a chassis ground;

a first input node configured to receive a first data signal;

a second input node configured to receive a second data signal that is complementary of the first data signal;

a buffer stage having a first node coupled to the first input node and a second node coupled to the second input node;

an amplifier stage having a fifth node coupled to a third node of the buffer stage, having a sixth node coupled to a signal ground, wherein the signal ground is not coupled to the header; and

an electro-optical transducer having an eighth node coupled to a seventh node of the amplifier stage and having a ninth node configured to be coupled to a voltage source, the electro-optical transducer being coupled to a fourth node of the buffer stage.

2. The transceiver of claim 1, further comprising a laser driver operably connected to the first and second input nodes, wherein the laser driver includes features for shaping the first and second data signals to produce an optimum transceiver output.

3. The transceiver of claim 2, wherein the active linear transmitter optical subassembly preserves the shaping of the first and second data signals by linearly amplifying the first and second data signals.

4. The transceiver of claim 1, further comprising a laser driver and a post amplifier, wherein the laser driver and the post amplifier are integrated within a single integrated circuit on the printed circuit board.

5. The transceiver of claim 4, further comprising a controller included on the printed circuit board that governs operation of the integrated laser driver and post amplifier.

6. The transceiver of claim 1, wherein the first and second input nodes include AC coupling capacitors.

7. The transceiver of claim 1, wherein:

the buffer stage includes two termination resistors, a capacitor and a first bipolar transistor;

the third node of the buffer stage includes an emitter terminal of the first bipolar transistor; and

the fourth node of the buffer stage includes a collector terminal of the first bipolar transistor.

8. The transceiver of claim 1, wherein:

the amplifier stage includes a second bipolar transistor;

the fifth node of the amplifier stage includes a base terminal of the second bipolar transistor;

the sixth node of the amplifier stage includes an emitter terminal of the second bipolar transistor; and

the seventh node of the amplifier stage includes a collector terminal of the second bipolar transistor.

9. The transceiver of claim 1, wherein, the signal ground is not a radio frequency (“

RF”

) ground.

10. The transceiver of claim 1, wherein the transceiver has a total power dissipation of no more than one Watt.

11. An optoelectronic transceiver, comprising:

a control module;

a persistent memory operably connected to the control module; and

an active linear transmitter optical subassembly, including;

a header;

a first input node configured to receive a first data signal;

a second input node configured to receive a second data signal that is complementary of the first data signal;

a first bipolar transistor having a base terminal coupled to the first and second input nodes;

a second bipolar transistor having a base terminal coupled to an emitter terminal of the first bipolar transistor and having an emitter terminal coupled to a signal ground, wherein the signal ground is not coupled to the header;

an electro-optical transducer having a first terminal configured to be coupled to a voltage source and being coupled to a collector terminal of the first bipolar transistor, the electro-optical transducer having a second terminal coupled to a collector terminal of the second bipolar transistor; and

a decoupling circuit coupled between the voltage source and the signal ground.

12. The transceiver of claim 11, further comprising a receiver optical subassembly that includes an opto-electrical transducer.

13. The transceiver of claim 12, further comprising a post amplifier operably connected to the receiver optical subassembly.

14. The transceiver of claim 13, further comprising a differential transmission line for carrying the first and second data signals from the laser driver to the active linear transmitter optical subassembly.

15. The transceiver of claim 11, wherein the active linear transmitter optical subassembly further comprises:

a first termination resistor having a first terminal coupled to the first input node and being coupled to the base terminal of the first bipolar transistor;

a second termination resistor having a first terminal coupled to the second input node and a second terminal coupled to a second terminal of the first termination resistor;

a termination capacitor, wherein a first terminal of the termination capacitor is coupled to the second terminal of the first termination resistor and to the second terminal of the second termination resistor;

a third resistor having a first terminal coupled to the emitter terminal of the first bipolar transistor and being coupled to the base terminal of the second bipolar transistor and it having a second terminal coupled to a second terminal of the termination capacitor and being coupled to the emitter terminal of the second bipolar transistor and being coupled to the signal ground.

16. The transceiver of claim 11, wherein emission of electromagnetic interference from the transceiver is controlled by the active linear transmitter optical subassembly.

17. The transceiver of claim 11, further comprising a printed circuit board upon which the control module and the persistent memory are disposed, wherein the amount of free space on the printed circuit board is maximized by including the first bipolar transistor and the second bipolar transistor within the active linear transmitter optical subassembly.

18. The transceiver of claim 11, wherein the active linear transmitter optical subassembly controls the size of an electromagnetic interference current loop defined in the transceiver.

19. The transceiver of claim 11, wherein the electro-optical transducer is a distributed feedback laser.

20. The transceiver of claim 11, wherein the decoupling circuit coupled between the voltage source and the signal ground includes a decoupling capacitor, wherein:

a first terminal of the decoupling capacitor is coupled to the collector terminal of the first bipolar transistor and to the first terminal of the electro-optical transducer; and

a second terminal of the decoupling capacitor is coupled to the signal ground.

21. An optoelectronic device, comprising:

a printed circuit board having a laser driver and a post amplifier disposed thereon;

a receiver optical subassembly operably coupled to the post amplifier; and

an active linear transmitter optical subassembly operably coupled to the laser driver, the transmitter optical subassembly including;

a header assembly electrically coupled to a chassis ground;

a first input node configured to receive a first data signal;

a second input node configured to receive a second data signal that is complementary of the first data signal;

a buffer stage having a first node coupled to the first input node and a second node coupled to the second input node, the buffer stage being configured to receive the first and second data signals from the first and second input nodes and convert the first and second data signals to a single-ended signal;

an amplifier stage having a first node coupled to a third node of the buffer stage and having a second node coupled to a signal ground, wherein the signal ground is not coupled to the chassis ground, the amplifier stage being configured to receive the single-ended signal from the buffer stage and linearly amplify the single-ended signal to produce an amplified single-ended signal; and

an electro-optical transducer having a first node coupled to a third node of the amplifier stage and having a second node coupled to a voltage source, the second node of the electro-optical transducer also being coupled to a fourth node of the buffer stage, wherein the electro-optical transducer is driven by the amplified single-ended signal to emit an optical signal representative of the amplified single-ended signal.

22. The optoelectronic package of claim 21, wherein:

the buffer stage comprises a first termination resistor, a second termination resistor, a termination capacitor, a third resistor and a first bipolar transistor;

the amplifier stage comprises a second bipolar transistor and a second resistor; and

the electro-optical transducer comprises a distributed feedback laser.

23. The optoelectronic package of claim 21, wherein the first and second data signals have been shaped to offset inherent imperfections in the electro-optical transducer prior to being received at the first and second input nodes.