OPTICAL COMMUNICATION MODULE AND FLEXIBLE PRINTED CIRCUIT BOARD

• US 20090263140A1
• Filed: 04/14/2009
• Published: 10/22/2009
• Est. Priority Date: 04/22/2008
• Status: Active Grant

• Current Assignee: Lumentum Japan, Inc. (Lumentum Holdings Inc.)
• Original Assignee: Opnext Japan, Inc. (Oclaro (Canada), Inc.)
• Inventors: KAGAYA, Osamu
• Granted Patent: US 7,986,020 B2
• Time in Patent Office: Days
• US Class Current: 398/139
• CPC Class Codes: H05K 1/0224 Patterned shielding planes, ground planes or power planes H05K1/0253 takes precedence
• CPC Class Codes: H05K 1/0234 Resistors or by disposing resistive or lossy substances in or near power planes H05K1/0246 takes precedence
• CPC Class Codes: H05K 1/0245 Lay-out of balanced signal pairs, e.g. differential lines or twisted lines
• CPC Class Codes: H05K 1/025 Impedance arrangements, e.g. impedance matching, reduction of parasitic impedance H05K1/024 and H05K1/0243 take precedence; for semiconductor devices H01L23/66
• CPC Class Codes: H05K 1/0253 Impedance adaptations of transmission lines by special lay-out of power planes, e.g. providing openings H05K1/0251 takes precedence
• CPC Class Codes: H05K 1/0393 Flexible materials H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups
• CPC Class Codes: H05K 1/147 at least one of the printed circuits being bent or folded, e.g. by using a flexible printed circuit H05K1/148 takes precedence
• CPC Class Codes: H05K 1/167 incorporating printed resistors
• CPC Class Codes: H05K 2201/09236 Parallel layout layout of balanced signal pairs H05K1/0245; superposed layout H05K2201/09672
• CPC Class Codes: H05K 2201/093 Layout of power planes, ground planes or power supply conductors, e.g. having special clearance holes therein reduction of cross-talk, noise or interference by patterned shielding planes, ground planes or power planes H05K1/0224
• CPC Class Codes: H05K 2201/0969 Apertured conductors
• CPC Class Codes: H05K 2201/09727 Varying width along a single conductor; Conductors or pads having different widths
• CPC Class Codes: H05K 2201/10121 Optical component, e.g. opto-electronic component

Abstract

A flexible printed circuit board includes: a signal wiring pattern including: a transmission line for connecting an end of an optical device with an end of a signal generation circuit; and another transmission line for connecting another end of the optical device with another end of the signal generation circuit; a thin film resistor layer formed in a region including a region facing the signal wiring pattern so as to constitute a first microstrip line together with each of the transmission lines; a ground conductor formed in a region except a part of a region facing the thin film resistor layer within a region including a region facing the signal wiring pattern so as to constitute a second microstrip line together with each of the transmission lines; and an insulating layer formed between each two of the signal wiring pattern, the thin film resistor layer, and the ground conductor.

Claims

1. An optical communication module, comprising:

an optical device;

a main board incorporating a signal generation circuit for generating a high frequency signal corresponding to an optical signal converted by the optical device; and

a flexible printed circuit board for connecting the optical device with the main board,

wherein the flexible printed circuit board comprises;

a signal wiring pattern comprising;

a first transmission line for connecting an end of the optical device with an end of the signal generation circuit; and

a second transmission line for connecting another end of the optical device with another end of the signal generation circuit;

a thin film resistor layer formed in a region including at least a part of a region facing the signal wiring pattern so as to constitute a first microstrip line together with each of the first transmission line and the second transmission line;

a ground layer formed in a region except a part of a region facing the thin film resistor layer within a region including a region facing the signal wiring pattern so as to constitute a second microstrip line together with the each of the first transmission line and the second transmission line; and

an insulating layer formed between each two of the signal wiring pattern, the thin film resistor layer, and the ground layer.

2. An optical communication module according to claim 1, wherein the signal wiring pattern is formed so that a space between the first transmission line and the second transmission line in a part facing the thin film resistor layer is smaller than a space in another part.

3. An optical communication module according to claim 2, wherein the first transmission line and the second transmission line are formed so that a width of the part facing the thin film resistor layer is larger than a width of the another part.

4. An optical communication module according to claim 1, wherein the ground layer is formed so that the part of the region facing the thin film resistor layer is an opening part.

5. An optical communication module according to claim 1, wherein the ground layer, the thin film resistor layer, and the signal wiring pattern are laminated in the stated order sandwiching the insulating layer.

6. An optical communication module according to claim 1, wherein the ground layer, the signal wiring pattern, and the thin film resistor layer are laminated in the stated order sandwiching the insulating layer.

7. An optical communication module according to claim 1, wherein the thin film resistor layer, the ground layer, and the signal wiring pattern are laminated in the stated order sandwiching the insulating layer.

8. A flexible printed circuit board for connecting an optical device with a main board incorporating a signal generation circuit for generating a high frequency signal corresponding to an optical signal converted by the optical device, the flexible printed circuit board comprising:

a signal wiring pattern comprising;

a first transmission line for connecting an end of the optical device with an end of the signal generation circuit; and

a second transmission line for connecting another end of the optical device and another end of the signal generation circuit;

a thin film resistor layer formed in a region including at least a part of a region facing the signal wiring pattern so as to constitute a first microstrip line together with each of the first transmission line and the second transmission line;

a ground layer formed in a region except a part of a region facing the thin film resistor layer within a region including a region facing the signal wiring pattern so as to constitute a second microstrip line together with the each of the first transmission line and the second transmission line; and

an insulating layer formed between each two of the signal wiring pattern, the thin film resistor layer, and the ground layer.