Abstract: Provided is a reflective colorless optical transmitter receiving a carrier signal, which is a continuous wave, and outputting a modulated optical signal. The reflective colorless optical transmitter includes a semiconductor optical amplifier (SOA) amplifying an input optical signal allowing the input optical signal to have a gain, an optical modulator connected to the SOA and outputting a modulated optical signal, a high reflectivity facet reflecting the modulated optical signal from the optical modulator, and a Bragg reflection mirror connected to the high reflectivity facet, the optical modulator, and the SOA in series, wherein a Bragg resonator is formed by the Bragg reflecting mirror and the high reflectivity facet.

Abstract: A distributed feedback-laser diode may include a substrate, a lower cladding layer having a grating on the substrate, an active layer disposed on the lower cladding layer, a first upper cladding layer disposed on the active layer, a phase-shift region extending in a first direction on the first upper cladding layer, and a ridge waveguide layer extending in a second direction crossing the first direction on the phase-shift region.

Abstract: Provided are an avalanche photodiode and a method of fabricating the same. The method of fabricating the avalanche photodiode includes sequentially forming a compound semiconductor absorption layer, a compound semiconductor grading layer, a charge sheet layer, a compound semiconductor amplification layer, a selective wet etch layer, and a p-type conductive layer on an n-type substrate through a metal organic chemical vapor deposition process.

Abstract: The present disclosure relates to a tunable laser module including a light gain area unit for outputting an optical signal; an optical distributor for separating the optical signal output from the light gain area unit; two comb reflection units for reflecting a part of optical signals separated by the optical distributor and allow a part of the optical signals to penetrate; two phase units for changing phases of the optical signals penetrating the two comb reflection units; an optical coupler for combining the optical signals of which the phases are changed by the two phase units; and an optical amplifier for amplifying the optical signal combined by the optical coupler, wherein the light gain area unit oscillates a laser by totally reflecting the optical signals reflected by the two comb reflection units.

Abstract: Provided are a high-speed superluminescent diode, a method of manufacturing the same, and a wavelength-tunable external cavity laser including the same. The superluminescent diode includes a substrate having an active region and an optical mode size conversion region, waveguides including an ridge waveguide in the active region and a deep ridge waveguide in the optical mode size conversion region connected to the active waveguide, an electrode disposed on the ridge waveguide; planarizing layers disposed on sides of the ridge waveguide and the deep ridge waveguide on the substrate, and a pad electrically connected to the electrode, the pad being disposed on the planarizing layers outside the active waveguide.

Abstract: Disclosed is a multi-channel receiver optical sub assembly. The a multi-channel receiver optical sub assembly includes: a multi-channel PD array, in which a plurality of photodiodes (PDs) disposed on a first capacitor, and including receiving areas disposed at centers thereof and anode electrode pads arranged in an opposite direction at an angle of 180 degrees based on the receiving areas between the adjacent PDs is monolithically integrated; a plurality of transimpedance amplifiers (TIAs) arranged on a plurality of second capacitors, respectively, and connected with the anode pads of the respective PDs through wire bonding; a submount on which the first capacitor.

Abstract: The present disclosure relates to an optical line terminal, the disclosure includes: an optical transmitter for generating a low speed downstream optical signal; a wavelength-multiplexer for wavelength-multiplexing the downstream optical signal; a first optical power branching tap coupler for allowing wavelength-multiplexed downstream optical signal to branch off; a wavelength band separator/coupler for separating between the wavelength-multiplexed downstream optical signal and a wavelength-multiplexed upstream optical signal; a circulation type wavelength-demultiplexer for wavelength-demultiplexing a downstream optical signal branched off by the first optical power branching tap coupler and an upstream optical signal separated by the wavelength band separator/coupler; an optical receiver for outputting a downstream electrical signal by using the wavelength-demultiplexed optical signal; and a signal processing module for controlling an optical power and a wavelength of the optical transmitter according to a s

Abstract: Distributed feedback-laser diodes are provided. The distributed feedback-laser diode may include a substrate, a lower cladding layer having a grating on the substrate, an active layer disposed on the lower cladding layer, a first upper cladding layer disposed on the active layer, a phase-shift region extending in a first direction on the first upper cladding layer, and a ridge waveguide layer extending in a second direction crossing the first direction on the phase-shift region.

Abstract: A multi-channel optical receiving module includes a first substrate disposed on a bench, optical fibers disposed in grooves of the first substrate, a first lens disposed on the first substrate and collimating optical signals through the optical fibers, a second substrate disposed on the bench at a side of the first substrate, a light receiving device disposed on the second substrate, a second lens disposed over the light receiving device, a mirror reflecting the optical signals between the first lens and the second lens, and a block fixing the mirror. The block includes through-holes transmitting the optical signals between the first and second lenses without refraction of the optical signals.

Abstract: The present disclosure relates to a compact external cavity tunable laser apparatus. The laser apparatus includes a substrate, an external cavity tunable reflecting unit that reflects laser light entering from the outside on the substrate and selects and varies a wavelength of the reflected laser light, an optical fiber that outputs the laser light on the substrate; and an highly integrated light source that integrates the laser light input from the external cavity tunable reflecting unit using inclined input and output waveguides, a curved waveguide, and a straight waveguide to output the integrated laser light to the optical fiber in order to match an optical axis formed with the external cavity tunable reflecting unit with an optical axis formed with an optical fiber.

Abstract: Disclosed is an optical line terminal for monitoring and controlling upstream and downstream optical signals, and more particularly, to an optical line terminal for monitoring and controlling upstream and downstream optical signals, which adds different low frequency monitoring signals to upstream and downstream wavelength division multiplexing optical signals in a bidirectional wavelength division multiplexing (WDM) optical network and senses and detects low frequency components of upstream and downstream optical signals to unite, monitor, and control optical outputs and wavelengths of the upstream and downstream wavelength division multiplexing optical signals into a single system.

Abstract: Disclosed is a wavelength-shifted bidirectional WDM optical network including: an optical line terminal including an optical line terminal (OLT) including a first optical transmitter transmitting a downstream WDM optical signal, a first high-density wavelength multiplexer/demultiplexer wavelength-multiplexing the downstream WDM optical signal or wavelength-demultiplexing a wavelength-multiplexed upstream WDM optical signal, and a first optical receiver receiving the wavelength-demultiplexed upstream WDM optical signal; a remote node (RN) including a second high-density wavelength multiplexer/demultiplexer shifting a center wavelength of the upstream WDM optical signal and wavelength-multiplexing the upstream WDM optical signal with the shifted center wavelength or wavelength-demultiplexing the wavelength-multiplexed downstream WDM optical signal; and multiple optical network units (ONUs) each including a second optical transmitter transmitting the upstream WDM optical signal and second optical receiver receiv

Abstract: A multi-channel optical receiving module includes a first substrate disposed on a bench, optical fibers disposed in grooves of the first substrate, a first lens disposed on the first substrate and collimating optical signals through the optical fibers, a second substrate disposed on the bench at a side of the first substrate, a light receiving device disposed on the second substrate, a second lens disposed over the light receiving device, a mirror reflecting the optical signals between the first lens and the second lens, and a block fixing the mirror. The block includes through-holes transmitting the optical signals between the first and second lenses without refraction of the optical signals.

Abstract: Provided is a wavelength division multiplexing (WDM) optical transmitting apparatus including first to n-th optical transmitters configured to output first to n-th optical signals having different wavelengths, respectively; a wavelength multiplexer configured to multiplex the first to n-th optical signals and generate an output optical signal; a tap coupler configured to receive the output optical signal and generate a controlling optical signal based on some of the output optical signal; a controlling photodetector configured to receive the controlling optical signal and output an optical current based on the controlling optical signal; and a controller configured to control each of the first to n-th optical transmitters based on the optical current, wherein the controller comprises a look-up table, sequentially detects driving conditions for the first to n-th optical transmitters, stores the detected driving conditions in the look-up table, and controls the first to n-th optical transmitters based on the de

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 an avalanche photodiode and a method of fabricating the same. The method of fabricating the avalanche photodiode includes sequentially forming a compound semiconductor absorption layer, a compound semiconductor grading layer, a charge sheet layer, a compound semiconductor amplification layer, a selective wet etch layer, and a p-type conductive layer on an n-type substrate through a metal organic chemical vapor deposition process.

Abstract: Provided are an avalanche photodiode and a method of fabricating the same. The method of fabricating the avalanche photodiode includes sequentially forming a compound semiconductor absorption layer, a compound semiconductor grading layer, a charge sheet layer, a compound semiconductor amplification layer, a selective wet etch layer, and a p-type conductive layer on an n-type substrate through a metal organic chemical vapor deposition process.

Abstract: The present disclosure relates to a compact external cavity tunable laser apparatus. The laser apparatus includes a substrate, an external cavity tunable reflecting unit that reflects laser light entering from the outside on the substrate and selects and varies a wavelength of the reflected laser light, an optical fiber that outputs the laser light on the substrate; and an highly integrated light source that integrates the laser light input from the external cavity tunable reflecting unit using inclined input and output waveguides, a curved waveguide, and a straight waveguide to output the integrated laser light to the optical fiber in order to match an optical axis formed with the external cavity tunable reflecting unit with an optical axis formed with an optical fiber.

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: Distributed feedback-laser diodes are provided. The distributed feedback-laser diode may include a substrate, a lower cladding layer having a grating on the substrate, an active layer disposed on the lower cladding layer, a first upper cladding layer disposed on the active layer, a phase-shift region extending in a first direction on the first upper cladding layer, and a ridge waveguide layer extending in a second direction crossing the first direction on the phase-shift region.