A display apparatus is provided. The display apparatus is a retinal scanning type display apparatus, and includes a low output laser whose operational current is less than that of a standard output laser; a shunting element that is connected in parallel with the low output laser; and a drive circuit that supplies a current to the low output laser and the shunting element. The drive circuit is a drive circuit for the standard output laser capable of adjusting a current value on a discrete basis in a range of an operational current that is higher than the operational current of the low output laser.

A system includes a master oscillator configured to generate a low-power optical beam. The system also includes a planar waveguide (PWG) amplifier configured to generate a high-power optical beam using the low-power optical beam. The PWG amplifier has a larger dimension in a slow-axis direction and a smaller dimension in a fast-axis direction. The system further includes at least one adaptive optic (AO) element configured to modify the low-power optical beam along the slow-axis direction and to modify the low-power optical beam along the fast-axis direction. In addition, the system includes a feedback loop configured to control the at least one AO element. The modification in the slow-axis direction can compensate for thermal-based distortions created by the PWG amplifier, and the modification in the fast-axis direction can compensate for optical misalignment associated with the master oscillator and the PWG amplifier.

A laser drive circuit compensates for laser diode dynamics. A compensation value is determined from a sum of weighted basis functions. The basis functions may be a function of current desired optical powers and/or past desired optical powers. The weights may be updated periodically based at least in part on accumulated basis function outputs and measured optical powers.

Provided is an optical transmission module in which noise is further reduced. The optical transmission module includes a first semiconductor layer having a first electrode arranged thereon, an active layer with a stripe shape formed on the first semiconductor layer, and a second semiconductor layer with a stripe shape formed on the active layer. The second semiconductor layer has a second electrode arranged thereon and includes a diffraction grating arranged along an extending direction of the active layer. The active layer includes a first portion having first stripe width, a second portion having a second stripe width smaller than the first stripe width, and a connection portion having a varying stripe width so as to connect the first portion and the second portion to each other. The diffraction grating overlaps with the first portion and does not overlap with the second portion in planar view.

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 communication system includes a laser that generates a laser light and a modulator that includes a modulation element configured to modulate the laser light with an input signal based on a bias voltage to produce an output signal. Control circuitry provides the bias voltage to a bias input of the modulation element and is configured to maintain a bias lock on at least two bias points of the modulation element during operation. The control circuitry is programmed to perform a bias lock operation that includes performing an initial voltage sweep on the modulation element and establish initial bias values for the at least two bias points. The circuit also providing a bias waveform to the bias input of the modulation element that varies over time and contains identifiable dither tones, determines harmonic power at the at least two bias points; and varies the bias waveform to determine harmonic power until the harmonic power is minimized to establish a bias lock with locked bias values.

The disclosure provides an optical module. In the optical module, emitters of a first PNP type triode and a second PNP type triode connected with a power source are high-level always, when a bias pin of a laser transmitter driver chip is high-level, bases of the two PNP type triodes are both high-level and in an OFF state, no current flows to the bias pin and a laser transmitter, and the laser transmitter does not emit light; when the bias pin of the laser transmitter driver chip is low-level, the bases of the two PNP type triodes are both low-level and in an ON state, the current flows to the bias pin and flows from a positive terminal of the laser transmitter, and the laser transmitter emits light.

Apparatus and associated methods relate to an open-loop control circuit (OLCC) configured to determine a lasing element drive current as a function of a commanded optical power signal and a measured temperature signal, where the absolute value of the second derivative of the optical output power with respect to laser drive current exceeds a predetermined threshold. In an illustrative example, the absolute value of the second derivative may exceed the predetermined threshold in a non-linear operating region of the laser element. The non-linear operating region may represent, for example, a characteristic output power vs. drive current curve of the lasing element. The OLCC may provide laser peak power control for arbitrary peak power, within linear and non-linear regions of laser efficiency. In some embodiments, the OLCC may substantially improve control over laser optical output power over a wide dynamic range of, for example, temperature associated with the lasing element.

A device includes a u-channel shaped member and a printed circuit board including a plurality of capacitors. Each of the plurality of capacitors has a mounting surface mounted to the printed circuit board and an opposing heat transfer surface thermally coupled to the u-channel shaped member. The device also includes an output cable coupled to the printed circuit board and a return cable coupled to the printed circuit board. The device further includes a control transistor disposed inside the u-channel shaped member and a current sensing resistor disposed inside the u-channel shaped member.

A method of controlling a semiconductor element that includes a semiconductor laser diode (LD), a semiconductor modulator, and a semiconductor optical amplifier (SOA) is disclosed. The LD generates CW light supplied with the first bias current. The semiconductor modulator generates a modulated light by modulating the CW light supplied with a driving signal. The SOA generates an optical signal by amplifying the modulated light supplied with the second bias current. The method first sets the second bias current in a region where the output power of the optical signal shows negative dependence of the second bias current. Then, a temperature of the semiconductor element, the first bias current, and the driving signal are adjusted such that the optical signal shows performance in respective preset ranges.