Optical module

1. An optical module, comprising:

a housing;

an optical adapter attached to an end portion of the housing; and

an optical transmitter and receiver assembly mounted in the housing,

wherein the optical transmitter and receiver assembly comprises a TOSA comprising a plurality of light-emitting elements for outputting optical signals, a ROSA comprising a light-receiving element for inputting optical signals, and a circuit board electrically connected to the TOSA and the ROSA,

wherein the TOSA further comprises a TOSA base arranged in an optical adapter side of the housing, the TOSA base including two side surfaces opposite and parallel to each other, the plurality of light-emitting elements being installed on the two parallel side surfaces respectively so that optical paths of light emitted from the plurality of light-emitting elements are parallel to each other,

wherein the circuit board comprises a first flexible substrate, which is mounted with the TOSA, and a first rigid substrate, which is coupled to the first flexible substrate, and

wherein the first flexible substrate comprises a TOSA base-facing portion, which is opposite the TOSA base, and a plurality of joining portions, which extend from both ends, respectively, of the TOSA base-facing portion and which are joined to the plurality of light-emitting elements respectively, wherein the plurality of joining portions comprise a first joining portion, which is joined to the light-emitting elements arranged on one of the two side surfaces, and a second joining portion, which is joined to the light-emitting elements arranged on another of the two side surfaces, wherein the first joining portion and the second joining portion extend from the TOSA base-facing portion, in directions opposite and parallel to each other.

2. The optical module according to claim 1 , wherein the circuit board has a two-level structure such that an upper level portion comprises the first flexible substrate and the first rigid substrate, and a lower level portion comprises a second rigid substrate that is connected to the first rigid substrate via a connecting flexible substrate.

3. The optical module according to claim 2 , wherein a transmission component is arranged and wired on the first rigid substrate and a reception component is arranged and wired on the second rigid substrate.

4. The optical module according to claim 2 , wherein the second flexible substrate mounting the ROSA is connected to the second rigid substrate.

5. The optical module according to claim 2 , wherein the second rigid substrate comprises an edge connector at an end portion thereof.

6. The optical module according to claim 1 , wherein the plurality of light-emitting elements are arranged on the TOSA base while being each housed in a CAN package.

7. An optical module, comprising:

a housing;

an optical adapter attached to an end portion of the housing; and

an optical transmitter and receiver assembly mounted in the housing,

wherein the optical transmitter and receiver assembly comprises a TOSA comprising a plurality of light-emitting elements for outputting optical signals, a ROSA comprising a light-receiving element for inputting optical signals, and a circuit board electrically connected to the TOSA and the ROSA,

wherein the TOSA is disposed on a side of the optical adapter in the housing and further comprises a TOSA base having opposing side surfaces on which the plurality of light-emitting elements are oppositely arranged so as to form at least one pair,

wherein the circuit board comprises a first flexible substrate mounting the TOSA and a first rigid substrate connected to the first flexible substrate,

wherein the first flexible substrate comprises a TOSA base facing-portion facing the TOSA base, and a connection portion extending from both end portions of the TOSA base-facing portion and connected to the plurality of light-emitting elements, and

wherein the TOSA base has a side surface formed into a stairs shape and the light-emitting element is placed on each stair.