Serial optical interconnect bus for logic cards and the like

• US 4,850,044 A
• Filed: 06/23/1988
• Issued: 07/18/1989
• Est. Priority Date: 06/23/1988
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Rocca, Charles J., Block, Timothy R., Soderstrom, Ronald L., Heiling, Gerald M.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Telesz, Jr., Andrew J.
• Application Number:
  US07/210,364
• Time in Patent Office: 390 Days
• Field of Search: 455/600, 455/601, 455/606, 455/607, 455/609, 455/613, 455/617, 350/96.11
• US Class Current: 398/118
• CPC Class Codes: H04B 10/803 Free space interconnects, e.g. between circuit boards or chips

Abstract

An optical serial data bus for connecting logic cards used in a data processing system. The bus uses semiconductor lasers and PIN diodes as transmitters and receivers, transmitting through free space without the use of lenses or other optical elements. Each logic card communicates only with the adjacent cards on either side to minimize the transmission distance.

Claims

1. In a data processing system having a plurality of logic cards parallel mounted in a supporting frame, optical serial data bus means connecting said cards comprising:

a. each of said cards so connected containing a first, electrically connected, optical data receiver-transmitter pair with the optical transmitter on a first side of said card and a second, electrically connected, optical data receiver-transmitter pair with the optical transmitter on a second, opposite side of said card;

b. said first optical transmitter-receiver pairs positioned on said logic cards to provide alignment therebetween when said cards are mounted in a supporting frame;

c. said second optical transmitter-receiver pairs positioned on said logic cards to provide alignment therebetween when said cards are mounted in a supporting frame;

d. each of said optical receivers positioned to receive data optically transmitted in free space from a single one of said logic cards;

e. each of said optical transmitters positioned to transmit data optically in free space to a single one of said logic cards; and

,

f. whereby said first pairs co-act to provide data transmission between said logic cards in a first direction, and said second pairs co-act to provide data transmission between said cards in a second direction.

2. An optical data bus according to claim 1 wherein the first and second pairs on the logic cards at the ends of said frame include optical connections to form a loop.

3. An optical data bus according to claim 2 wherein said optical connections comprise mirror means supported on said frame.

4. An optical data bus according to claim 2 wherein said optical connections comprise fiber optic elements.

5. A optical data bus according to claim 1 wherein said optical transmitters comprise semiconductor lasers operating in the 780 nm range.

6. An optical data bus according to claim 5 wherein said optical receivers comprise PIN diodes.

7. An optical data bus according to claim 1 wherein the first and second pairs on the logic cards at the ends of said frame are electrically connected to form a loop.

8. An optical data bus according to claim 1 wherein said optical receivers comprise PIN diodes.

9. A planar logic card for use in a data processing system comprising:

a. a first side of said logic card having a first semiconductor laser and a first optical receiver positioned thereon at first and second spaced apart locations;

b. a second side of said logic card having a second semiconductor laser and a second optical receiver positioned thereon at third and fourth spaced apart locations geometrically corresponding to said second and first locations, respectively;

c. first circuit means electrically connecting said first laser and said second optical receiver; and

,

d. second circuit means electrically connecting said second laser and said first optical receiver whereby said card is adapted to utilize, modify or relay data optically transmitted to said first or second optical receivers.

10. A planar logic card according to claim 9 wherein said logic card is polarized to restrict mounting to a single position whereby said first second, third and fourth locations are respectively positioned abutting the third and fourth locations of a card adjacent said first side and abutting the first and second locations of a card adjacent said second side to receive data optically transmitted in flee space from said adjacent cards and to transmit data optically in free space to said adjacent cards.

11. A logic card according to claim 10 wherein said first laser and said second optical receiver are located at a same first coordinate on opposite sides of said card.

12. A logic card according to claim 11 wherein said second laser and said first optical receiver are located at a same second coordinate, spaced apart from said first coordinate, on opposite sides of said card.

13. A logic card according to claim 10 wherein said semiconductor lasers operate in the region of 780 nm, and said optical receivers are PIN diodes.