Consistent with the present disclosure, a local oscillator is provided in a receiver. The local oscillator laser a first and second mirrors and phase section and heaters are provided adjacent each portion of the laser, such that the temperature and thus the frequency of light output from the local oscillator laser may be tuned. Applying electrical power, such as a current or voltage to the phase section may result in rapid frequency tuning of light output from the local oscillator laser but over a limited frequency range. Temperature changes to the mirror sections, however, may afford frequency tuning over a wider range, but frequency tuning the mirror sections requires more time than that required to tune the phase section. Consistent with the present disclosure, a tuning method and apparatus is provided that optimizes laser tuning by selectively tuning the phase and mirror sections.

Provided are an optical apparatus, a manufacturing method of a distributed Bragg reflector laser diode, and a manufacturing method of the optical apparatus, the an optical apparatus including a cooling device, a distributed Bragg reflector laser diode having a lower clad including a recess region on one side of the cooling device and connected to another side of the cooling device, and an air gap between the cooling device and the distributed Bragg reflector laser diode, wherein the air gap is defined by a bottom surface of the lower clad in the recess region and a top surface of the cooling device.

A semiconductor laser device includes a semiconductor substrate, a resonator unit formed on the semiconductor substrate and having an active layer, a diffraction grating formed on or underneath the active layer, a front facet of an inverted mesa slope, and a rear facet, an anti-reflection coating film formed on the front facet, a reflective film formed on the rear facet, an upper electrode formed on the resonator unit, and a lower electrode formed underneath the semiconductor substrate, wherein a length in a resonator direction of the resonator unit is shorter than a length in the resonator direction of the semiconductor substrate, and a laser beam is emitted from the front facet.

A laser comprising a laser cavity formed by a broadband mirror and a comb mirror having a plurality of reflection peaks. A spacing between the plurality of reflection peaks is adjusted such that only one reflection peak is in a gain bandwidth of the laser.

A tunable wavelength laser comprising a laser cavity formed by a broadband mirror and a comb mirror. The laser cavity comprising a gain region. The laser cavity is configured such that a non-integer number of cavity modes of the laser cavity are between two consecutive reflection peaks of the comb mirror.

A tunable laser has a first mirror, a second mirror, a gain medium, and a directional coupler. The first mirror and the second mirror form an optical resonator. The gain medium and the directional coupler are, at least partially, in an optical path of the optical resonator. The first mirror and the second mirror comprise binary super gratings. Both the first mirror and the second mirror have high reflectivity. The directional coupler provides an output coupler for the tunable laser.

A method includes receiving a mode control signal indicative of a current-mode or a voltage-mode. When the mode control signal is indicative of the voltage-mode, the method includes connecting a voltage-mode bias sub-circuit to an anode of a reflector-section diode and applying an adjustable bias voltage to bias a diode voltage at the anode of the reflector-section diode. The reflector-section diode is disposed on a shared substrate of a tunable laser. When the mode control signal is indicative of the current-mode, the method includes connecting a current-mode bias sub-circuit to the anode of the reflector-section diode and delivering an adjustable bias current to the anode of the reflector-section diode.

A tunable wavelength laser comprising a laser cavity formed by a broadband mirror and a comb mirror. The laser cavity comprising a gain region. The laser cavity is configured such that a non-integer number of cavity modes of the laser cavity are between two consecutive reflection peaks of the comb mirror.

A laser comprising a laser cavity formed by a broadband mirror and a comb mirror having a plurality of reflection peaks. A spacing between the plurality of reflection peaks is adjusted such that only one reflection peak is in a gain bandwidth of the laser.

Provided are an optical apparatus, a manufacturing method of a distributed Bragg reflector laser diode, and a manufacturing method of the optical apparatus, the an optical apparatus including a cooling device, a distributed Bragg reflector laser diode having a lower clad including a recess region on one side of the cooling device and connected to another side of the cooling device, and an air gap between the cooling device and the distributed Bragg reflector laser diode, wherein the air gap is defined by a bottom surface of the lower clad in the recess region and a top surface of the cooling device