Optical transmitter and optical module including the same
An optical transmitter and an optical module including the optical transmitter are provided. The optical transmitter may include a support substrate, a temperature control module disposed on the support substrate, a sub-mount disposed on the temperature control module, a prism disposed on the temperature control module and having a sloped surface, a light receiving element disposed on the temperature control module, a light emitting element disposed on the sub-mount, and a thermistor disposed on the sub-mount. The light receiving element may be disposed separately from the sub-mount in a first direction, and the prism may be disposed between the light receiving element and the sub-mount. Some first light emitted from the light emitting element may be reflected by the sloped surface of the prism, and some of the first light may pass through the prism and be received by the light receiving element.
1. An optical transmitter comprising:
a support substrate;
a temperature control module disposed on the support substrate;
a sub-mount disposed on the temperature control module;
a light receiving element disposed on the temperature control module;
a prism disposed on the temperature control module and having a sloped surface, the prism being disposed between the light receiving element and the sub-mount;
a light emitting element disposed on the sub-mount;
an optical fiber disposed on the sub-mount and in optical communication with the prism; and
a thermistor disposed on the sub-mount,
wherein:
the light receiving element is disposed separately from the sub-mount in a first direction and is disposed adjacent to the prism on the temperature control module,
a first portion of light emitted from the light emitting element is reflected by the sloped surface of the prism and emitted through a lens,
a second portion of the light passes through the prism and is received by the light receiving element in such a way that a light output from the light emitting element is directly monitored by the light receiving element, and
the sloped surface of the prism is angled such that a light coupling efficiency between the emitted light and the optical fiber is increased.
2. The optical transmitter of claim 1 , wherein the temperature control module includes:
a first pad disposed on the support substrate;
a second pad disposed on the first pad; and
one or more thermoelectric semiconductors disposed between the first pad and the second pad.
3. The optical transmitter of claim 2 , wherein the prism, the light receiving element, and the sub-mount are disposed on the second pad.
4. The optical transmitter of claim 2 , wherein the second pad includes a conductive layer electrically coupled to the light receiving element.
5. The optical transmitter of claim 4 , wherein the second pad includes an aligning groove formed on the conductive layer, and the prism is disposed in the aligning groove.
6. The optical transmitter of claim 1 , wherein:
the light emitting element includes a first side which emits the light toward the prism and a second side which faces the first side; and
one surface of the thermistor is disposed to face the second side of the light emitting element.
7. The optical transmitter of claim 6 , wherein an angle formed by the one surface of the thermistor and the second side of the light emitting element is in a range of 25 degrees to 45 degrees.
8. The optical transmitter of claim 1 , wherein the light emitting element includes:
a first side which emits the light forward toward the prism;
a second side which faces the first side; and
a third side and a fourth side which connect the first side and the second side, wherein the thermistor is disposed adjacent to the third side.
9. The optical transmitter of claim 1 , wherein:
a width of the sub-mount is greater than a width of the temperature control module; and
each of the width of the sub-mount and the width of the temperature control module is a length in a second direction perpendicular to the first direction.
10. The optical transmitter of claim 1 , wherein a difference between a width of the sub-mount and a width of the temperature control module is in a range of about 0.2 mm to 0.4 mm.
11. The optical transmitter of claim 1 , further comprising:
a plurality of first lead electrodes disposed along one side of the temperature control module; and
a plurality of second lead electrodes disposed along the other side of the temperature control module, wherein the one side and the other side of the temperature control module are sides parallel to the first direction.
12. The optical transmitter of claim 1 , further comprising:
a housing disposed on the support substrate to protect optical components; and wherein the lens is disposed on the housing to collect the light reflected by the sloped surface.
13. The optical transmitter of claim 1 , wherein an angle of the sloped surface of the prism is between about 41 degrees and about 49 degrees.
14. The optical transmitter of claim 1 , wherein the sloped surface of the prism has an angle satisfying the following expression:
θ 3 =45°±θ 1 /2,
where θ 3 denotes an angle of the sloped surface, and θ 1 denotes a polishing angle of a cross section of an optical fiber of a receptacle.