Electro-magnetic interference reduction filter for an optical transceiver
View Patent ↗An optical transmit circuit that includes an electro-optic transducer driver and an electro-magnetic interference (“EMI”) reduction filter. The EMI reduction filter is coupled to an output terminal of the electro-optic transducer driver. This allows the EMI reduction filter to receive an electrical signal from the transducer driver. The EMI reduction filter then filters out a significant portion of the EMI of concern from the electrical signal.
1. An optical transmit circuit comprising:
an electro-optic transducer driver having at least one output terminal, the at least one output terminal comprising a first electro-optic transducer driver output terminal; and
an electro-magnetic interference reduction filter coupled to the at least one output terminal of the electro-optical transducer driver so as to receive and filter a signal received from the electro-optical transducer driver, the electro-magnetic interference reduction filter comprising:
a first inductor having a first terminal coupled to the first electro-optic transducer driver output terminal; and
a first capacitor having a first terminal coupled to the first terminal of the first inductor, and having a second terminal coupled to a second terminal of the first inductor and to a first output terminal of the electro-magnetic interference reduction filter.
2. An optical transmit circuit in accordance with claim 1 , further comprising:
an electro-optical transducer coupled to the electro-magnetic interference reduction filter so as to convert electrical signals received from the electro-optical transducer into corresponding optical signals.
3. An optical transmit circuit in accordance with claim 2 , wherein the electro-optical transducer comprises a laser.
4. An optical transmit circuit in accordance with claim 2 , wherein the electro-optical transducer comprises a Light Emitting Diode (LED).
5. An optical transmit circuit in accordance with claim 1 , wherein the electro-magnetic interference reduction filter further comprises the following:
a second capacitor; and
a second inductor coupled in series with the second capacitor between the first output terminal of the electro-magnetic interference reduction filter and a voltage source.
6. An optical transmit circuit in accordance with claim 5 , wherein the first capacitor and first inductor are sized to maximize filtration at a first frequency, and the second capacitor and second inductor are sized to maximize filtration at a second frequency that is different than the first frequency.
7. An optical transmit circuit in accordance with claim 6 , wherein the first frequency is approximately six gigahertz, and the second frequency is approximately eight gigahertz.
8. An optical transmit circuit in accordance with claim 6 , wherein the first frequency is approximately eight gigahertz, and the second frequency is approximately six gigahertz.
9. An optical transmit circuit in accordance with claim 1 , wherein the at least one output terminal of the electro-optic transducer driver further comprises a second electro-optic transducer driver output terminal, the electro-magnetic interference reduction filter further comprising the following:
a second inductor having a first terminal coupled to the second electro-optic transducer driver output terminal; and
a second capacitor having a first terminal coupled to the first terminal of the second inductor, and having a second terminal coupled to a second terminal of the second inductor and to a second output terminal of the electro-magnetic interference reduction filter.
10. An optical transmit circuit in accordance with claim 9 , further comprising:
a third capacitor having a first terminal coupled to the second terminal of the first inductor and to the first output terminal of the electro-magnetic interference reduction filter;
a fourth capacitor having a first terminal coupled to the second terminal of the second inductor and to the second output terminal of the electro-magnetic interference reduction filter; and
a third inductor having a first terminal coupled to a second terminal of the third capacitor and a second terminal of the fourth capacitor, and having a second terminal coupled to a voltage source.
11. An optical transmit circuit in accordance with claim 9 , wherein the electro-magnetic interference reduction filter further comprises the following:
a third capacitor; and
a third inductor coupled in series with the third capacitor between the first output terminal of the electro-magnetic interference reduction filter and a first voltage source.
12. An optical transmit circuit in accordance with claim 11 , wherein the electro-magnetic interference reduction filter further comprises the following:
a fourth capacitor; and
a fourth inductor coupled in series with the fourth capacitor between the second output terminal of the electro-magnetic interference reduction filter and a second voltage source.
13. An optical transmit circuit in accordance with claim 12 , wherein the first and second voltage sources are the same.
14. An optical transmit circuit in accordance with claim 12 , wherein the first and second voltage sources are different.
15. An optical transmit circuit in accordance with claim 1 , wherein the electro-optical transducer driver is situated within an optical transceiver module.
16. An optical transmit circuit in accordance with claim 1 , wherein the electro-optical transducer driver is situated within an optical transceiver host.
17. An optical transmit circuit in accordance with claim 1 , wherein the optical transmit circuit is an optical transceiver.
18. An optical transmit circuit comprising:
an electro-optical transducer driver having a first output terminal and a second output terminal;
an electro-magnetic interference reduction filter comprising the following:
a first inductor having a first terminal coupled to the first electro-optic transducer driver output terminal;
a first capacitor having a first terminal coupled to the first terminal of the first inductor, and having a second terminal coupled to a second terminal of the first inductor and to a first output terminal of the electro-magnetic interference reduction filter;
a second capacitor;
a second inductor coupled in series with the second capacitor between the first output terminal of the electro-magnetic interference reduction filter and a voltage source;
a third inductor having a first terminal coupled to the second electro-optic transducer driver output terminal;
a third capacitor having a first terminal coupled to the first terminal of the third inductor, and having a second terminal coupled to a second terminal of the third inductor and to a second output terminal of the electro-magnetic interference reduction filter;
a fourth capacitor; and
a fourth inductor coupled in series with the fourth capacitor between the second output terminal of the electro-magnetic interference reduction filter and a second voltage source; and
an electro-optical transducer coupled to the electro-magnetic interference reduction filter so as to convert electrical signals received from the electro-optical transducer into corresponding optical signals.
19. An optical transmit circuit in accordance with claim 18 , wherein the optical transmit circuit is an optical transceiver.
20. An optical transmit circuit comprising:
an electro-optical transducer driver having a first output terminal and a second output terminal;
an electro-magnetic interference reduction filter comprising the following:
a first inductor having a first terminal coupled to the first electro-optic transducer driver output terminal;
a first capacitor having a first terminal coupled to the first terminal of the first inductor, and having a second terminal coupled to a second terminal of the first inductor and to a first output terminal of the electro-magnetic interference reduction filter;
a second inductor having a first terminal coupled to the second electro-optic transducer driver output terminal;
a second capacitor having a first terminal coupled to the first terminal of the second inductor, and having a second terminal coupled to a second terminal of the second inductor and to a second output terminal of the electro-magnetic interference reduction filter a third capacitor having a first terminal coupled to the second terminal of the first inductor and to the first output terminal of the electro-magnetic interference reduction filter;
a fourth capacitor having a first terminal coupled to the second terminal of the second inductor and to the second output terminal of the electro-magnetic interference reduction filter; and
a third inductor having a first terminal coupled to a second terminal of the third capacitor and a second terminal of the fourth capacitor, and having a second terminal coupled to a voltage source.