A multi-channel laser source, including: a bus waveguide coupled, at an output end of the bus waveguide, to an output of the multi-channel laser source; a first semiconductor optical amplifier; a first back mirror; a first wavelength-dependent coupler, having a first resonant wavelength, on the bus waveguide; a second semiconductor optical amplifier; a second back mirror; and a second wavelength-dependent coupler, on the bus waveguide, having a second resonant wavelength, different from the first resonant wavelength. In some embodiments the first semiconductor optical amplifier is coupled to the bus waveguide by the first wavelength-dependent coupler, which is nearer to the output end of the bus waveguide than the second wavelength-dependent coupler, the second semiconductor optical amplifier is coupled to the bus waveguide by the second wavelength-dependent coupler, and the first wavelength-dependent coupler is configured to transmit light, at the second resonant wavelength, along the bus waveguide.

A temperature controlled multi-channel transmitter optical subassembly (TOSA), consistent with embodiments described herein, may be used in a multi-channel optical transceiver. The temperature controlled multi-channel TOSA generally includes an array of lasers to emit a plurality of different channel wavelengths. The lasers may be thermally tuned to the channel wavelengths by establishing a global temperature for the array of lasers such that the amount of heat communicated to each laser is substantially the same. The global temperature may be established, at least in part, by monitoring the shortest channel wavelength and/or a temperature of the lasers. The temperature of the lasers may then get increased via a shared heating device in thermal communication with the lasers until the shortest monitored wavelength substantially reaches the nominal shortest wavelength or the measured temperature substantially equals the global temperature.

A semiconductor laser module that includes a package accommodating therein a plurality of optical components, includes: a semiconductor laser device that emits laser light toward one end side in the package; an optical fiber having an incident end of the laser light on another end side in the package, the another end being in an opposite direction of an emission direction in which the semiconductor laser device emits the laser light; and a turn-back unit that turns back the laser light toward the another end side in the package, the another end being in the opposite direction of the emission direction in which the semiconductor laser device emits the laser light, and outputs the laser light to the incident end of the optical fiber.

An apparatus and method for calculating the frequency of the light.

An on-chip laser includes a gain portion, a mirror in communication with the gain portion, a waveguide in communication with the gain portion, and a resonator optically coupled to the waveguide at an optical coupling. The resonator has a circular shape. The waveguide and the resonator are separate from the gain portion.

A multi-channel laser source, including: a bus waveguide coupled, at an output end of the bus waveguide, to an output of the multi-channel laser source; a first semiconductor optical amplifier; a first back mirror; a first wavelength-dependent coupler, having a first resonant wavelength, on the bus waveguide; a second semiconductor optical amplifier; a second back mirror; and a second wavelength-dependent coupler, on the bus waveguide, having a second resonant wavelength, different from the first resonant wavelength. In some embodiments the first semiconductor optical amplifier is coupled to the bus waveguide by the first wavelength-dependent coupler, which is nearer to the output end of the bus waveguide than the second wavelength-dependent coupler, the second semiconductor optical amplifier is coupled to the bus waveguide by the second wavelength-dependent coupler, and the first wavelength-dependent coupler is configured to transmit light, at the second resonant wavelength, along the bus waveguide.

An optical transmission system includes a laser module generating a modulated optical waveform, including both amplitude and frequency modulation, at center frequencies corresponding to different operating temperatures; and an optical shaping filter, with passbands corresponding to the different center frequencies, that converts at least part of the frequency modulation to additional amplitude modulation. The optical transmission system is tuned by: determining a range of temperatures at which the laser module center frequencies are within a passband of the optical shaping filter; setting the laser module to a temperature, within the range of temperatures, at which the modulated optical waveform is within the passband; measuring an average output power of the optical shaping filter; and adjusting the temperature of the laser module to a target temperature, within the range of temperatures, at which an output condition is achieved, based on the average output power and/or extinction ratio of the filtered waveform.

The present invention is intended to reduce variations in oscillation wavenumber of a semiconductor laser element due to the influence of circumferential temperatures. The invention includes a semiconductor laser semiconductor laser element, a temperature control part to control a temperature of the semiconductor laser element, a temperature sensor to detect a temperature of the temperature control part, and a temperature control device to control a supply signal to the temperature control part so that a detected temperature obtained from the temperature sensor reaches a predetermined target temperature. The temperature control device changes a target temperature for the temperature control part depending on a supply signal to the temperature control part.

The present invention provides a wavelength control method, a system thereof and a shutoff depth control circuit. The method includes: enabling a current temperature of TEC (6) to be rapidly stabilized at a target temperature through a closed loop control of hardware PID (8); allowing the shut-off depth control circuit (11) to operate when a burst driver (5) that drives a light emitting assembly (3) is standby or operating, providing an input to the light emitting assembly (3) through the shut-off depth control circuit (11) so that the light-emitting assembly (3) can emit the light that does not affect the normal operations of other ONU, the light emitted allows the light emitting assembly (3) to be warmed up, which enables the light emitting assembly (3) to quickly stabilize the emitted light within the bandwidth required by each channel of the system during the time period from a non-light emitting state to a light emitting state.

An atomic oscillator includes a semiconductor laser, an atomic cell, a light receiving element, a first temperature control element, and a second temperature control element. The semiconductor laser includes a first mirror layer, a second mirror layer, and an active layer disposed between the first mirror layer, the second mirror layer, and a heat transfer member disposed on the second mirror layer. The atomic cell is irradiated with light emitted from the semiconductor laser. In the atomic cell, an alkali metal atom is accommodated. The light receiving element detects intensity of light transmitted through the atomic cell and outputs a detection signal. The first temperature control element controls a temperature of the semiconductor laser. The second temperature control element is controlled based on the detection signal and is connected to the heat transfer member.