| abstract |
In a wavelength tunable laser, high output is realized while the operation is not unstable. A wavelength tunable laser is formed by a waveguide including a silicon waveguide core, and the interval between resonance wavelengths that periodically exist is different from each other, and the first ring resonator and the second ring can shift the resonance wavelength. A first ring resonance comprising a wavelength filter 3 including a resonator 2 and an integrated element 6 optically connected to the wavelength filter and provided with a first semiconductor optical amplifier 4 and a reflecting mirror 5 in order from the wavelength filter side. The resonant wavelengths that periodically exist in the resonator and the second ring resonator coincide with each other at one wavelength, and also coincide with each other at a plurality of other wavelengths other than the one wavelength. The resonance wavelength interval of the first ring resonator and the second ring resonator is set so that the recurring mode interval, which is the interval with the wavelength closest to one wavelength, is wider than the reflection wavelength range of the reflector. thing To. [Selection] Figure 1 |