The invention relates to a method for controlling a semiconductor-laser-diode-based SS-interferometer system (SS=swept source), which allows for a wide range of application and is suitable for use in ophthalmology, in particular for imaging and for determining biometric measurement values of the eye. In the method according to the invention, by means of periodic current modulation, the operation of single semiconductor laser diodes is designed such that a highly coherent spectral laser line can be adjusted with a highest possible repetition rate and over a wide wavelength range. In addition, the following parameters: centre wavelength, sweep rate, sweep range, optical power in the eye and coherence length are adjusted such that the method is suitable for imaging and biometric applications via whole-eye scans. The proposed semiconductor-laser-diode-based SS-interferometer system is provided, in particular, for biometric measuring of the eye. Given that the embodiments are based preferably on optical, coherence tomographic scan images, the main application lies in opthalmological diagnostics, treatment and the preparation of surgical procedures and follow-up thereof.

Disclosed herein are multi-layered optically active regions for semiconductor light-emitting devices (LEDs) that incorporate intermediate carrier blocking layers, the intermediate carrier blocking layers having design parameters for compositions and doping levels selected to provide efficient control over the carrier injection distribution across the active regions to achieve desired device injection characteristics. Examples of embodiments discussed herein include, among others: a multiple-quantum-well variable-color LED operating in visible optical range with full coverage of RGB gamut, a multiple-quantum-well variable-color LED operating in visible optical range with an extended color gamut beyond standard RGB gamut, a multiple-quantum-well light-white emitting LED with variable color temperature, and a multiple-quantum-well LED with uniformly populated active layers.

Disclosed herein are multi-layered optically active regions for semiconductor light-emitting devices (LEDs) that incorporate intermediate carrier blocking layers, the intermediate carrier blocking layers having design parameters for compositions and doping levels selected to provide efficient control over the carrier injection distribution across the active regions to achieve desired device injection characteristics. Examples of embodiments discussed herein include, among others: a multiple-quantum-well variable-color LED operating in visible optical range with full coverage of RGB gamut, a multiple-quantum-well variable-color LED operating in visible optical range with an extended color gamut beyond standard RGB gamut, a multiple-quantum-well light-white emitting LED with variable color temperature, and a multiple-quantum-well LED with uniformly populated active layers.

Disclosed herein are multi-layered optically active regions for semiconductor light-emitting devices (LEDs) that incorporate intermediate carrier blocking layers, the intermediate carrier blocking layers having design parameters for compositions and doping levels selected to provide efficient control over the carrier injection distribution across the active regions to achieve desired device injection characteristics. Examples of embodiments discussed herein include, among others: a multiple-quantum-well variable-color LED operating in visible optical range with full coverage of RGB gamut, a multiple-quantum-well variable-color LED operating in visible optical range with an extended color gamut beyond standard RGB gamut, a multiple-quantum-well light-white emitting LED with variable color temperature, and a multiple-quantum-well LED with uniformly populated active layers.

A surface emitting laser has a Vertical-Cavity Surface emitting laser (VCSEL) structure. The VCSEL structure includes an aperture provided by a current confinement structure. An optically discontinuous portion is formed in a top Distributed Bragg Reflector (DBR) of the VCSEL structure such that it is arranged in a region with a gap between it and the aperture.

Systems and methods described herein are directed to optical light sources, such as an external cavity laser (ECL) with an active phase shifter. The system may include control circuity for controlling one or more parameters associated with the active phase shifter. The phase shifter may be a p-i-n phase shifter. The control circuitry may cause variation in a refractive index associated with the phase shifter, thereby varying a lasing frequency of the ECL. The ECL may be configured to operate as a light source for a light detection and ranging (LIDAR) system based on generating frequency modulated light signals. In some embodiments, the ECL may generate an output LIDAR signal with alternating segments of increasing and decreasing chirp frequencies. The ECL may exhibit increased stability and improved chirp linearities with less dependence on ambient temperature fluctuations.

An optical device includes a light-emitting device integrated with a memory device. The memory device include a first electrode and a second electrode, and the light-emitting device includes a third electrode and the second electrode. In such configuration, a first voltage between the second electrode and the third electrode causes the light-emitting device to emit light of a first wavelength, and a second voltage between the first electrode and the second electrode while the memory device is at OFF state causes the light-emitting device to emit light of a second wavelength shorter than the first wavelength or while the memory device is at ON state causes the light-emitting device to emit light of a third wavelength longer than the first wavelength.

The present invention provides a widely tunable, single mode emission semiconductor laser which comprises a semiconductor substrate, a first linear ridge waveguide which forms a first coupled cavity, and a second linear ridge waveguide which forms a second coupled cavity, with the first coupled cavity being separated from the second coupled cavity by a gap. The first and second coupled cavities comprise p-contacts and n-contacts for allowing laser currents I.sub.1, I.sub.2 to be injected into the first and second coupled cavities, respectively. The first and second coupled cavities comprise first and second heating resistors, respectively, for heating the first and second coupled cavities when heating currents H.sub.1, H.sub.2 are applied to the first and second heating resistors, respectively. A heating resistor is provided for heating the semiconductor substrate of the semiconductor laser so as to regulate the base temperature T of the chip (i.e., the semiconductor substrate).

Methods, devices and systems for improving single-frequency operation of diode lasers are described. One such method includes ramping up an operational current of a diode laser for a first predetermined number of steps, and measuring an associated current value indicative of optical power within the laser diode for each of the first predetermined number of steps. Next, operational current of the diode laser is ramped down for a second predetermined number of steps, and an associated current value indicative of optical power within the laser diode is measured for each of the second predetermined number of steps. Using the measured data current values at which a mode hop or a multimode operation is likely to occur are identified, and a contiguous range of operating currents that is devoid of identified likely mode hops or multimode regions of operation is determined as the operating current range of the diode laser.

Improved optical coherence tomography systems and methods to measure thickness of the retina are presented. The systems may be compact, handheld, provide in-home monitoring, allow the patient to measure himself or herself, and be robust enough to be dropped while still measuring the retina reliably.