Tunable laser source
The invention relates to a tunable laser source, and the reduction in the loss and the size can both be achieved in a tunable laser source having a power monitor and a wavelength locker function. A tunable laser is formed of a semiconductor optical amplifier and a resonator, and one of the two output light beams split from part of the light within the tunable laser by a 2×2 type optical splitter is incident into a light intensity monitor, and the other is incident into a wavelength locker.
1. A tunable laser source, comprising:
a single semiconductor optical amplifier that outputs one part of amplified light from one end as output light and another part of the amplified light from another end;
a resonator that forms a tunable laser together with the semiconductor optical amplifier and that receives the other part of the amplified light outputted from the other end of the semiconductor optical amplifier;
a 2×2 type optical splitter that is optically coupled with the semiconductor optical amplifier and the resonator and that splits part of the light within the tunable laser into two light beams;
a light intensity monitor into which one light beam from among the two light beams split by the optical splitter enters from a resonator side of the optical splitter; and
a wavelength locker into which the other light beam from among the two light beams split by the optical splitter enters from a semiconductor optical amplifier side of the optical splitter.
2. The tunable laser source according to claim 1 , wherein the optical splitter is a directional coupler.
3. The tunable laser source according to claim 1 , wherein the optical splitter is a multimode interference coupler.
4. The tunable laser source according to claim 1 , wherein the optical splitter is crossing waveguides.
5. The tunable laser source according to claim 1 , wherein the resonator is formed of a silicon photonic wire.
6. The tunable laser source according to claim 5 , wherein the light intensity monitor has a germanium layer layered on top of a silicon layer.
7. The tunable laser source according to claim 1 , wherein at least the semiconductor optical amplifier, the resonator, the optical splitter and the light intensity monitor are formed of a III-V compound semiconductor in a monolithic manner.
8. The tunable laser source according to claim 1 , wherein the optical splitter is a directional coupler.
9. The tunable laser source according to claim 1 , wherein the optical splitter is a multimode interference coupler.
10. The tunable laser source according to claim 1 , wherein the optical splitter is crossing waveguides.
11. The tunable laser source according to claim 1 , wherein the resonator is formed of a silicon photonic wire.
12. The tunable laser source according to claim 11 , wherein the light intensity monitor has a germanium layer layered on top of a silicon layer.
13. The tunable laser source according to claim 1 , wherein at least the semiconductor optical amplifier, the resonator, the optical splitter and the light intensity monitor are formed of a III-V compound semiconductor in a monolithic manner.