An optical module includes an LD that emits laser beam; a carrier that mounts the LD and thermistor thereon; a photodetector detecting the laser beam output from the LD; a TEC that mounts the carrier and the photodetector thereon; a chassis having a box-shape demarcated by walls that form a space for enclosing the LD, the TEC, and the photodetector therein, wherein at least of the walls has a window, and the thermistor arranged between the LD and the photodetector.

A method for tuning an emission wavelength of a laser device, including: acquiring a drive condition of a wavelength tunable laser diode to make the wavelength tunable laser diode oscillate at a wavelength from a memory; driving a first thermo-cooler and a first heater based on the drive condition of the wavelength tunable laser diode; determining whether respective control values of the first thermo-cooler and the first heater are reached within a first range of target values; and driving a gain region after the control values have been reached within the first range.

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 waveguide based wavelength-tunable laser formed on a semiconductor substrate includes a first reflector from which laser light is output, a second reflector configuring a laser resonator together with the first reflector, a gain portion that is provided between the first reflector and the second reflector, at least two wavelength filters that can adjust wavelength characteristics and adjust a wavelength of the laser light, and a phase adjuster that adjusts an optical path length in the laser resonator, and a waveguide is formed to fold back an optical path by an angle of substantially 180 degrees between the first reflector and the second reflector.

In a DBR laser of a wavelength-tunable transmitter, a rear DBR region, an active region, and a front DBR region are integrated along an optical axis direction. The diffraction grating structure is set so that an oscillation mode using a reflection peak on the shortest wavelength side among a plurality of reflection peaks corresponding to the wavelength-tunable band is easily oscillated the most in a state where a current to the two DBR regions of the SSG-BPFR is 0. The SSG-DBR laser is configured such that the average period value of the diffraction grating of the front DBR is larger than the average period value of the diffraction grating of the rear DBR. The diffraction grating is configured so that the wavelengths of the reflection peaks on the shortest wavelength side among the plurality of reflection peaks coincide with each other between the two DBR regions in a state where no current is supplied.

A method for sweeping an electromagnetic radiation source (12) to produce single mode operation having an optimized side-mode suppression ratio over a continuous range of wavelengths within a prescribed temporal profile, the electromagnetic radiation source is configured to output electromagnetic radiation at a given wavelength based upon parameters. The method includes determining a set of parameter combinations that satisfy a condition for a desired set of wavelengths and a maximum side mode suppression ratio over the range of wavelengths. The set of parameter combinations define sub-paths for transitioning from one wavelength to another wavelength. Combinations of select sub-paths provide a multivariate path for transitioning over the range of wavelengths. The method also includes controlling the semiconductor laser to emit electromagnetic radiation over the range of wavelengths by traversing the multivariate path in a desired manner.

An on-chip wavelength locker may include an optical waveguide splitter to split an input optical signal received from a laser. The on-chip wavelength locker may include a plurality of integrated periodic optical elements, each to receive a respective portion of the input optical signal after splitting of the input optical signal by the optical waveguide splitter, and provide, based on the respective portion of the input optical signal, a respective periodic output optical signal of a plurality of periodic output optical signals. Each periodic output optical signal, of the plurality of periodic output optical signals, may be phase shifted with respect to other periodic output optical signals of the plurality of periodic output optical signals. The on-chip wavelength locker may include a plurality of integrated photodiodes to receive the plurality of periodic output optical signals in association with wavelength locking the laser.

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 method for controlling an electromagnetic radiation source to produce single mode operation having an optimized side-mode suppression ratio over a set of wavelengths within a prescribed temporal profile. The electromagnetic radiation source is configured to output electromagnetic radiation at a given wavelength based upon parameters. The method includes determining a set of parameter combinations that satisfy a condition for a desired set of wavelengths and a minimum side mode suppression ratio over the range of wavelengths. The set of parameter combinations define sub-paths for nearly arbitrary transitions from one wavelength to another wavelength. Combinations of select sub-paths provide a multivariate path for transitioning over the range of wavelengths. The method also includes controlling the semiconductor laser to emit electromagnetic radiation over the range of wavelengths by traversing the multivariate path in a desired manner.

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.