A semiconductor laser source includes a partial-grating DFB laser with two laser electrodes, one over the grating and the other between the grating and one end of the laser. Constant laser currents flow into the waveguide through the electrodes (typically different from each other) and produce laser output. A wavelength discriminator, an optical detector, and a wavelength-control circuit act as a wavelength-control feedback mechanism to generate a wavelength control current that flows through one laser electrode or the other, or through both electrodes with opposite polarities. Phase noise on the laser output can be reduced at modulation frequencies exceeding several hundred kHz up to one or several tens of MHz or more. The laser-wavelength can be swept while exhibiting reduced phase noise.

The present invention relates to a technical field of optical communications. It relates to a dual-rate DML device and module, and a calibration method, and in particular, to a dual-rate DML device and module having a built-in signal calibration circuit, and a calibration method. According to the present invention, the signal calibration circuit is added into the device; a PD is prepositioned by means of a novel light splitting structure; a control structure for a sequence-divided multi-channel serial signal is utilized to feed back a monitoring signal to an electric driver to adjust drive current; crosstalk between backlight monitoring is reduced; and high-quality signal output under dual modulation frequencies of 25 Gbps and 28 Gbps is realized.

The upper surface of the semiconductor substrate has a slope descending from the projection in the second direction at an angle of 0-12 to a horizontal plane. The mesa stripe structure has an inclined surface with a slope ascending from the upper surface of the semiconductor substrate at an angle of 45-55 to the horizontal plane, the mesa stripe structure having an upright surface rising from the inclined surface at an angle of 85-95 to the horizontal plane. The buried layer is made from semiconductor with ruthenium doped therein and is in contact with the inclined surface and the upright surface. The inclined surface is as high as 80% or less of height from the upper surface of the semiconductor substrate to a lower surface of the quantum well layer and is as high as 0.3 m or more.

Methods for driving a tunable laser with integrated tuning elements are disclosed. The methods can include modulating the tuning current and laser injection current such that the laser emission wavelength and output power are independently controllable. In some examples, the tuning current and laser injection current are modulated simultaneously and a wider tuning range can result. In some examples, one or both of these currents is sinusoidally modulated. In some examples, a constant output power can be achieved while tuning the emission wavelength. In some examples, the output power and tuning can follow a linear relationship. In some examples, injection current and tuning element drive waveforms necessary to achieve targeted output power and tuning waveforms can be achieved through optimization based on goodness of fit values between the targeted and actual output power and tuning waveforms.

A system for controlling an optical intensity and modulation of an optical data transmitter which includes current driver circuitry configured to provide a drive current to a laser diode wherein said current comprises a fixed component and a modulated component, said modulated component having a magnitude related to an input data stream. The monitor circuitry contains a photodiode and a first transimpedance amplifier coupled to said photodiode, said monitor circuitry configured to provide an output signal related to an optical intensity of said laser diode. The system further includes replica monitor circuitry containing a replica capacitor with a replica capacitance and a second transimpedance amplifier configured to be substantially identical in construction to said first transimpedance amplifier, said second transimpedance amplifier coupled to said replica capacitor. The system further includes replica capacitance control circuitry configured to control said replica capacitance of said replica capacitor to match a capacitance associated with said photodiode.

A DFB laser DC-coupled output power configuration scheme with adjustable voltage difference. utilizes an external or internal power configuration unit to provide two electric DC power supplies with a fixed voltage difference for the transmitting unit TX of the DFB laser and the optical transceiver integrated chip, and at the same time optimizes the transmitting unit TX. The optimization scheme is that: the transistors in the transmitting unit TX are all low-voltage high-speed tubes, the transmitting unit TX includes a negative capacitance structure composed of capacitors C1 and C2, serving as an auxiliary structure for improving bandwidth. After optimization, the minimum voltage of the power supply voltage port TVCC of the transmitting unit TX is 2.7V and the problems that the output eye diagram is severely cracked and cannot be used when the traditional DFB laser configuration scheme with an external 3.3V power supply is tested at high temperature are solved.

A laser module with a flattened structure is installed on a mobile device for a camera program installed in the mobile device to operate photo-taking and image measurement. The laser module includes a printed circuit board (PCB), a photodiode embedded on the PCB, an automatic power control integrated circuit embedded on the PCB, and a laser diode chip electrically connected to the PCB. The flattened structure has a top surface of the PCB, a detection surface of a photodiode chip, a first surface of the automatic power control integrated circuit, a connecting surface of the laser diode chip sharing a common plane surface for operation.

A laser diode control circuit includes: a LD driver circuit for driving a laser diode; a direct current component remover circuit for generating a feedback signal based on a detected signal; a first conversion and filter circuit for generating a first filtered signal based on the feedback signal; a first rectifier for rectifying the first filtered signal to generate a first rectified signal; a reference signal generator for generating a reference signal; a second conversion and filter circuit for generating a second filtered signal based on the reference signal; a second rectifier for rectifying the second filtered signal to generate a second rectified signal; a rectified signals processing circuit for generating a processed signal based on the first and second rectified signals; and a comparator for generating a comparison signal based on the processed signal.

A laser module with a flattened structure is installed on a mobile device for a camera program installed in the mobile device to operate photo-taking and image measurement. The laser module includes a printed circuit board (PCB), a photodiode embedded on the PCB, an automatic power control integrated circuit embedded on the PCB, and a laser diode chip electrically connected to the PCB. The flattened structure has a top surface of the PCB, a detection surface of a photodiode chip, a first surface of the automatic power control integrated circuit, a connecting surface of the laser diode chip sharing a common plane surface for operation.

A system comprising drive circuitry configured to apply in a start-up phase a first drive current and then a second different drive current to a laser diode, the first drive current and second drive current being such that the laser diode is configured to provide a first optical output and a second optical output respectively. The system further comprising an optical sensor configured to provide a first sensor output corresponding to the first optical output of the laser diode and a second sensor output corresponding to the second optical output. The system further comprises a controller configured to use a value of the first drive current, a value of the second drive current, the first sensor output, the second sensor output and at least one supplied input value to provide control values for the drive circuitry to control an operating current of the laser diode, wherein the system is arranged to be used in a communication system wherein information is transmitted in at least one burst.