Abstract: Provided are a spot size converter and a method of manufacturing the spot size converter. The method includes stacking a lower clad layer, a core layer, and a first upper clad layer on a substrate, tapering the first upper clad layer and the core layer in a first direction on a side of the substrate, forming a waveguide layer on the first upper clad layer and the lower clad layer, and etching the waveguide layer, the first upper clad layer, the core layer, and the lower clad layer such that the waveguide layer is wider than a tapered portion of the core layer on the side of the substrate and has the same width as that of the core layer on another side of the substrate.

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: 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: 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: Provided are a spot size converter and a method of manufacturing the spot size converter. The method includes stacking a lower clad layer, a core layer, and a first upper clad layer on a substrate, tapering the first upper clad layer and the core layer in a first direction on a side of the substrate, forming a waveguide layer on the first upper clad layer and the lower clad layer, and etching the waveguide layer, the first upper clad layer, the core layer, and the lower clad layer such that the waveguide layer is wider than a tapered portion of the core layer on the side of the substrate and has the same width as that of the core layer on another side of the substrate.

Abstract: Provided is a multichannel transmitter optical module which includes a plurality of light source units configured to generate light, a plurality of an electro-absorption modulators (EAMs) configured to modulate the generated light to an optical signal through a radio frequency (RF) signal, a plurality of RF transmission lines configured to apply the RF signal to the EAMs, and a combiner configured to combine the modulated optical signal. The RF transmission lines are connected to the EAMs in a traveling wave (TW) electrode manner. The multichannel transmitter optical module has alleviated crosstalk and is compactly integrated to have a small size.

Abstract: Provided are a distributed feedback laser diode and a manufacturing method thereof. The distributed feedback laser diode includes a first area having a first grating layer disposed in a longitudinal direction, a second area disposed adjacent to the first area and having a second grating layer disposed in the longitudinal direction, and an active layer disposed over the first and second areas. Coupling coefficients of the first and second grating layers are made different in the first and second areas by a selective area growth method. The distributed feedback laser diode includes grating layers each having an asymmetric coefficient and is implemented within an optimal range capable of obtaining both a high front facet output and stable single mode characteristics. Thus, high manufacturing yield and low manufacturing cost can be achieved.

Abstract: The present invention relates to a potentially inexpensive light for multi-channel wavelength-division-multiplexed (WDM) applications. The high-power amplified spontaneous emission (ASE) from a fiber amplifier, which is already in the optical fiber, is efficiently divided into many channels using a WDM demultiplexer. This "spectrum-sliced" ASE is used as light sources for WDM systems rather than several wavelength-selected DFB lasers.

Abstract: A method for synchronizing an etalon to a preselected set of optical frequencies includes the step of generating a transmission spectrum for an etalon having a characteristic free spectral range that is a function of its effective length. The optical frequencies for the transmission spectrum are provided by two optical reference frequencies such as produced by a first and second frequency locked laser. The effective length of the etalon is set in relation to the optical reference frequencies.

Abstract: A tunable etalon filter is formed by placing mirrors on either side of a spacer of a material which has a relatively large rate of change of refractive index with temperature, and coupling the filter to a thermoelectric cooler to control the temperature of the spacer and, therefore, the index of refraction of the spacer. More specifically, the spacer can be a silicon wafer, or a wafer of zinc sulfide or zinc selenide. The mirrors can be formed of quarter wavelength layer pairs of dielectric coatings of high and low refractive index material. The thermoelectric cooler, which can be coupled to a heat sink, controls the temperature of the spacer by either heating or cooling the spacer. In operation the filter is coarse tuned by adjusting its angle relative to the angle of a received optical signal. It is then fine tuned to the signal by adjusting the temperature of the spacer.

Abstract: A compact all-fiber, electrically tunable ring laser includes a diode-pumped erbium-doped fiber amplifier. The frequency of the laser is tuned by a fiber Fabry-Perot (FFP) etalon that is electrically tuned. An in-line optical isolator is used in conjunction with the FFP to eliminate undesired reflections. A second FPP with a narrow free spectral range (FSR) can be used in conjunction with a first FFP with a wide FSR.

Abstract: A compact all-fiber, electrically tunable ring laser includes a diodepumped erbium-doped fiber amplifier. The frequency of the laser is tuned by a fiber Fabry-Perot(FFP) etalon that is electrically tuned. An in-line optical isolator is used in conjunction with the FFP to eliminate undesired reflections. A second FFP with a narrow free spectral range (FSR) can be used in conjunction with a first FFP with a wide FSR.

Abstract: Frequency stabilization of a long wavelength semiconductor laser is achieved by employing the optogalvanic effect in a feedback control loop with the laser. Absolute references are obtained using noble gases such as argon (1.2 .mu.m to 1.4 .mu.m) and krypton (1.4 .mu.m to 1.6 .mu.m). Standard detection, feedback control and dithering lock-in techniques are used to insure proper frequency stabilization.

Abstract: Heterodyne and homodyne lightwave communication systems require transmitter optical sources and receiver local oscillators to be locked to a particular frequency. In accordance with the present invention, each transmitter laser and each receiver local oscillator laser is independently and locally stabilized to the same absolute frequency standard using species exhibiting atomic or molecular absorption lines in the wavelength range of interest. Frequency stabilization of the lasers is achieved by employing an optogalvanic effect element in a feedback control loop with the laser. Absolute frequency standards are obtained using gas discharge tubes containing, for example, noble gases such as argon (1.2 .mu.m to 1.4 .mu.m) and krypton (1.4 .mu.m to 1.6 .mu.m) and the like. Standard synchronous detection and feedback control techniques are used to insure proper long-term frequency stability.