Abstract: A wearable device may include: an analog watch unit that includes a time indicating unit that indicates time, and a drive unit that drives the time indicating unit; a touch screen that senses an input for adjusting the drive unit; and a control unit that controls the drive unit in response to the sensed input.

Abstract: Provided herein is a semiconductor light emitting device capable of increasing the light extraction efficiency and a fabricating method thereof, the device including a buffer layer formed on a substrate; an n-type semiconductor layer formed on the buffer; an active layer formed on a partial area of the n-type semiconductor layer such that the n-type semiconductor layer is exposed; a p-type semiconductor layer formed on the active layer; a transparent conductive layer formed on the p-type semiconductor layer; a first mesa surface formed along a side wall of the active layer from a side wall of the transparent conductive layer; a passivation layer formed along the first mesa surface; and a metal reflectance film formed along the passivation layer such that it re-reflects escaping light, thereby re-reflecting escaping light to increase the light extraction efficiency.

Abstract: A semiconductor optical device includes a first mode converting core, a light amplification core, a second mode converting core, and a light modulation core disposed in a first mode converting region, a light amplification region, a second mode converting region, and a light modulating region of a semiconductor substrate, respectively, and a current blocking section covering at least sidewalls and a top surface of the light amplification core. The first mode converting core, the light amplification core, the second mode converting core, and the light modulation core are arranged along one direction in the order named, and are connected to each other in butt joints. The current blocking section includes first, second, and third cladding patterns sequentially stacked. The second cladding pattern is doped with dopants of a first conductivity type, and the first and third cladding patterns are doped with dopants of a second conductivity type.

Abstract: A coupler structure of a mobile terminal having a repeater applied thereto is provided. The coupler structure includes a first substrate having a reception coupler, a second substrate having a transmission coupler, and a repeater disposed between the first substrate and the second substrate.

Abstract: A near field wireless communication apparatus using a magnetic coupling to transmit data or clock information with low power and high efficiency is provided. Thus, when data to be transmitted is “1,” the near field wireless communication apparatus modulates the data into a pulse signal and transmits the pulse signal, and when the data is “0,” the near field wireless communication apparatus does not generate a signal at all.

Abstract: An optical amplifier includes a passive waveguide region and an active waveguide region. The passive waveguide region is configured to receive an incident optical signal and adjust a mode of the optical signal. The active waveguide region is integrated to the passive waveguide region and configured to perform gain modulation on the optical signal received from the passive waveguide region by changing density of carriers in response to a current applied to the active waveguide region. Internal loss of the active waveguide region is adjusted to produce a resonance effect and thereby to increase bandwidth of the active waveguide. Therefore, the optical amplifier can have a wide bandwidth under a low-current condition.

Abstract: A semiconductor optical device includes a first mode converting core, a light amplification core, a second mode converting core, and a light modulation core disposed in a first mode converting region, a light amplification region, a second mode converting region, and a light modulating region of a semiconductor substrate, respectively, and a current blocking section covering at least sidewalls and a top surface of the light amplification core. The first mode converting core, the light amplification core, the second mode converting core, and the light modulation core are arranged along one direction in the order named, and are connected to each other in butt joints. The current blocking section includes first, second, and third cladding patterns sequentially stacked. The second cladding pattern is doped with dopants of a first conductivity type, and the first and third cladding patterns are doped with dopants of a second conductivity type.

Abstract: Provided are a semiconductor optical amplifier and an optical signal processing method using the same. The reflective semiconductor optical amplifier includes: an optical signal amplification region operating to allow a downward optical signal incident from the external to obtain a gain; and an optical signal modulation region connected to the optical signal amplification region and generating a modulated optical signal. The downward optical signal is amplified through a cross gain modulation using the modulated optical signal and is outputted as an upward optical signal.

Abstract: Provided is an optical device module that can improve miniaturization and integration. The optical device module includes a semiconductor optical amplifier having a buried structure and including a first active layer buried in a clad layer disposed on a first substrate, an optical modulator in which a sidewall of a second active layer disposed in a direction of the first active layer on a second substrate junctioned to the first substrate is exposed, the optical modulator having a ridge structure, and at least one multi-mode interference coupler in which the second active layer junctioned to the first active layer is buried in the clad layer, the multi-mode interference coupler sharing the second active layer on the second substrate between the optical modulator and the semiconductor optical amplifier and integrated with the second optical device.

Abstract: Provided is a semiconductor laser diode having a waveguide lens. The semiconductor laser diode includes at least one first waveguide having a narrow width, at least one second waveguide having a wide width wider, and at least one waveguide lens having an increasing width from the first waveguide toward the second waveguide and connecting the first waveguide to the second waveguide. Sidewalls of the waveguide lens connecting the first waveguide to the second waveguide may be curved. The second waveguide may be a waveguide providing an optical gain.

Abstract: Provided is a wavelength division multiplexed-passive optical network (WDM-PON) apparatus. The WDM-PON includes an optical source unit, an optical mux, and a chirped Bragg grating. The optical source unit generates an optical signal. The optical mux receives the optical signal from the optical source unit through one end of the optical mux, multiplexes the optical signal, and outputs the multiplexed optical signal. The chirped Bragg grating is connected to the other end of the optical mux. The chirped Bragg grating again reflects the optical signal having passed the optical mux to re-input a certain portion of the optical signal into the optical mux and the optical source unit. The optical mux performs a spectrum slicing on the re-inputted optical signal and operates the optical source unit using a channel wavelength of the optical mux as a main oscillation wavelength.

Abstract: Provided is a frequency-tunable terahertz light source device. The frequency-tunable terahertz light source device satisfies a Littrow diffraction condition at a wavelength and simultaneously satisfies a Littman-Metcalf diffraction condition at another wavelength using a double diffraction grating having two grating periods. Thus, oscillations simultaneously occur at the two different wavelengths, such that a terahertz wave can be stably generated by beating of the two oscillation wavelengths. In addition, the frequency-tunable terahertz light source device can readily change a frequency up to several terahertz and can be fabricated in a small size.

Abstract: An optical amplifier includes a passive waveguide region and an active waveguide region. The passive waveguide region is configured to receive an incident optical signal and adjust a mode of the optical signal. The active waveguide region is integrated to the passive waveguide region and configured to perform gain modulation on the optical signal received from the passive waveguide region by changing density of carriers in response to a current applied to the active waveguide region. Internal loss of the active waveguide region is adjusted to produce a resonance effect and thereby to increase bandwidth of the active waveguide. Therefore, the optical amplifier can have a wide bandwidth under a low-current condition.

Abstract: Provided are a laser diode generating passive mode locking that does not contain non-linear sector of an SA, and a method of creating an optical pulse using the same diode. The laser diode includes a DFB sector serving as a reflector and a gain sector. The gain sector is connected to the DFB sector and includes an as-cleaved facet formed at the end of the gain sector. When a current less than a threshold current is applied to the DFB sector to allow the DFB sector to operate as a reflector, passive mode locking occurs swiftly and therefore a sector of the SA is not required, which makes manufacturing simple. Also, it is possible to effectively extend a frequency variable region compared to using of the SA.

Abstract: Provided are a semiconductor optical amplifier and an optical signal processing method using the same. The reflective semiconductor optical amplifier includes: an optical signal amplification region operating to allow a downward optical signal incident from the external to obtain a gain; and an optical signal modulation region connected to the optical signal amplification region and generating a modulated optical signal. The downward optical signal is amplified through a cross gain modulation using the modulated optical signal and is outputted as an upward optical signal.

Abstract: A multi-section semiconductor laser diode is disclosed. The laser diode includes a complex-coupled DFB laser section that includes a complex-coupled grating and an active structure for controlling the intensity of oscillating laser light, to oscillate laser light in a single mode, and an external cavity including a phase control section and an amplifier section, the phase control section having a passive waveguide that controls a phase variation of feedback laser light, the amplification section having an active structure that controls the strength of the feedback laser light. Currents are separately provided to the three sections to generate optical pulses with tuning range of tens of GHz. Applications include the clock recovery in the 3R regeneration of the optical communication.

Abstract: A full 3R (re-timing, re-shaping, re-amplifying) recovery system is provided. In the full 3R recovery system, a self-pulsating laser diode (SP-LD) and an electroabsorption modulator (EAM) are integrated and disposed on a semiconductor substrate.

Abstract: A wavelength tunable laser diode using a double coupled ring resonator is provided. A new double coupled ring resonator structure is formed by a connection of two ring resonators having different radii so that stable laser oscillation occurs only in a resonant wavelength at which the two ring resonators are simultaneously resonated, and the effective refractive index of the two ring resonators is properly controlled differently for tunable laser oscillation wavelengths. The reproducibility of the optical coupling characteristics of the passive waveguides and the ring resonator can be assured by multi-mode couplers. This results in improved manufacturing productivity of the wavelength tunable laser diode. It is possible to amplify and output an output light without having an effect on oscillation wavelength characteristic by means of an optical amplifier integrated in an output end.

Abstract: Provided is a frequency-tunable terahertz light source device. The frequency-tunable terahertz light source device satisfies a Littrow diffraction condition at a wavelength and simultaneously satisfies a Littman-Metcalf diffraction condition at another wavelength using a double diffraction grating having two grating periods. Thus, oscillations simultaneously occur at the two different wavelengths, such that a terahertz wave can be stably generated by beating of the two oscillation wavelengths. In addition, the frequency-tunable terahertz light source device can readily change a frequency up to several terahertz and can be fabricated in a small size.

Abstract: The 3R regeneration system for a retiming, reshaping, and reamplifying an optical signal includes: first and second input ports in which a connected optical signal is input; an interferometer including first and second branches formed on a substrate, split at a common input node, combined at a common output node, semiconductor optical amplifiers in each of the first and second branches, the first branch being connected to the first input port, and the common input node being connected to the second input port; a self-pulsating laser diode monolithically integrated with the interferometer between one of the first input port and the first branch, and the second input port and the common input node on the substrate, receiving an optical signal, and outputting the optical signal regenerated by optical injection locking; and an output port connected to the common output node.