Optical apparatus, manufacturing method of distributed Bragg reflector laser diode and manufacturing method of optical apparatus

1. A manufacturing method of a distributed Bragg reflector laser diode, the manufacturing method comprising:

forming gratings in a lower clad;

forming a waveguide comprising a passive waveguide on the gratings and an active waveguide connected to the passive waveguide;

forming an upper clad on the waveguide;

forming a plurality of upper electrodes on the upper clad;

forming a lower electrode layer below the lower clad; and

etching a part of the lower electrode layer below the gratings and a part of the lower clad to form a lower electrode and a recess region,

wherein when a thickness of the lower clad is 100 μm, the lower clad is etched to 80 μm or thinner, and the gratings are formed in a depth equal to or greater than 5 μm from a bottom surface of the lower clad in the recess region.

2. The manufacturing method of claim 1 , further comprising:

forming an insulation layer between one of upper electrodes and the upper clad,

wherein when the insulation layer has a thickness of 100 nm, the recess region is formed in a depth of 45 μm.

3. The manufacturing method of claim 1 , wherein the lower clad is etched to have a thickness equal to or greater than 3 μm between a bottom surface of the gratings and a bottom surface of the lower clad in the recess region.

4. The manufacturing method of claim 1 , wherein the recess region comprises trenches formed in a line shape.

5. The manufacturing method of claim 1 , wherein the recess region comprises holes and the holes arranged in a honeycomb shape.

6. The manufacturing method of claim 1 , wherein the upper electrodes comprise:

a first upper electrode on the active waveguide;

a second upper electrode adjacent to the first upper electrode and formed on the passive waveguide; and

a third upper electrode adjacent to the second upper electrode and formed on the passive waveguide,

wherein the third upper electrode is used as a heater electrode configured to heat the passive waveguide.

7. The manufacturing method of claim 6 , further comprising:

forming first and second Ohmic contact layers between the upper clad and the first and second upper electrodes.

8. The manufacturing method of claim 7 , further comprising:

providing first to third pads on the first to third upper electrodes,

wherein the first and second Ohmic contact layers, the first and second upper electrodes, and the first and second pads are provided in a laminated structure of titanium/platinum/gold.

9. The manufacturing method of claim 8 , wherein the third upper electrode and the third pad respectively comprise chromium and gold.

10. A manufacturing method of an optical apparatus, the method comprising:

forming a distributed Bragg reflector laser diode;

forming bumps below the distributed Bragg reflector laser diode;

bonding a cooling device to the bumps,

wherein a manufacturing method of the distributed Bragg reflector laser diode comprises:

forming gratings in a lower clad;

forming a waveguide comprising a passive waveguide on the gratings and an active waveguide connected to the passive waveguide;

forming an upper clad on the waveguide;

forming a plurality of upper electrodes on the upper clad;

forming a lower electrode layer below the lower clad; and

etching a part of the lower electrode layer below the gratings and a part of the lower clad to provide a lower electrode and a recess region,

wherein when a thickness of the lower clad is 100 μm, the lower clad is etched to 80 μm or thinner, and the gratings are formed in a depth equal to or greater than 5 μm from a bottom surface of the lower clad in the recess region.

11. The manufacturing method of claim 10 , wherein the lower clad below the passive waveguide and the cooling device form an air gap and the air gap is formed larger than a depth of a bottom surface of the lower clad in the recess region.

12. The manufacturing method of claim 10 , wherein the cooling device comprises:

a thermocouple; and

a metal optical bench between the thermocouple and the bumps.

13. The manufacturing method of claim 10 , wherein the cooling device comprises:

a thermocouple;

a mount block between the thermocouple and the bumps; and

a metal pattern formed and earthed between the mount block and the bumps.

14. The manufacturing method of claim 13 , wherein the mount block comprises ceramic.