An optoelectronic device and method of making the same. The device comprising: a substrate; an epitaxial crystalline cladding layer, on top of the substrate; and an optically active region, above the epitaxial crystalline cladding layer; wherein the epitaxial crystalline cladding layer has a refractive index which is less than a refractive index of the optically active region, such that the optical power of the optoelectronic device is confined to the optically active region.

An optical modulator combines and inputs a signal light propagating through the optical network and a control light having information concerning the optical network to a nonlinear optical medium. The optical modulator modulates the signal light according to changes in intensity of the control light, in the nonlinear optical medium.

An optical modulator combines and inputs a signal light propagating through the optical network and a control light having information concerning the optical network to a nonlinear optical medium. The optical modulator modulates the signal light according to changes in intensity of the control light, in the nonlinear optical medium.

In a signal regeneration device in which recovery of a signal quality which has been degraded during transmission in optical communication and extension of a transmission distance are achieved, the most representative method of quantizing an optical phase is a phase sensitive amplifier (PSA) and a technique that utilizes an optical parametric process through use of a highly nonlinear optical medium, but there is a demand for a technique of quantizing an optical phase which is not accompanied with an optical parametric gain, has small-sized elements, is easily integrated, and does not require high power pump light. By a technique of a hybrid optical phase squeezer (HOPS), when a phase of input light is quantized to M levels (M>2), phase conjugate light of the input light and (M1)th phase harmonic light of the input light are subjected to power modulation to be coherently added, so that quantization of the optical phase is performed through use of a simple four-wave mixing (FWM) that is not accompanied with the optical parametric gain and a general optical amplifier by using a general nonlinear optical medium such as silicon, and accordingly, a GER of equal to or higher than 30 dB can be obtained, even if a nonlinear optical element having a low nonlinearity is used.

In a signal regeneration device in which recovery of a signal quality which has been degraded during transmission in optical communication and extension of a transmission distance are achieved, the most representative method of quantizing an optical phase is a phase sensitive amplifier (PSA) and a technique that utilizes an optical parametric process through use of a highly nonlinear optical medium, but there is a demand for a technique of quantizing an optical phase which is not accompanied with an optical parametric gain, has small-sized elements, is easily integrated, and does not require high power pump light. By a technique of a hybrid optical phase squeezer (HOPS), when a phase of input light is quantized to M levels (M>2), phase conjugate light of the input light and (M1)th phase harmonic light of the input light are subjected to power modulation to be coherently added, so that quantization of the optical phase is performed through use of a simple four-wave mixing (FWM) that is not accompanied with the optical parametric gain and a general optical amplifier by using a general nonlinear optical medium such as silicon, and accordingly, a GER of equal to or higher than 30 dB can be obtained, even if a nonlinear optical element having a low nonlinearity is used.

Provided are a relay apparatus and a relay method for a passive optical network so as to largely extend a communicable distance while maintaining compatibility with existing network components. In the case of applying an optical relay to the passive optical network, a delay time is reduced by applying the optical relay so that entire transmission delay time considering the increased delay time may be within a preamble period of the upstream burst stream, thereby rapidly increasing a transmission distance of the passive optical network by using the optical relay.

According to one embodiment, a communication repeater system includes a master station device, slave station devices, radio frequency units that convert signals from base station systems into optical digital signals for transmission to the master station device. The base station systems establish communication by time-division duplex scheme. The communication repeater system repeats communication between a mobile communication terminal device and each base station system via a corresponding slave station device. At least one of the radio frequency units and the master and slave station devices includes a learning-signal input port, and a setter that generates a reference transmission/reception switching timing signal based on a learning signal input to the learning-signal input port and sets the generated signal as reference transmission/reception switching timing. The rest of the units and the devices each include a corrector that corrects variation in transmission/reception switching timing according to the reference transmission/reception switching timing.

According to one embodiment, a communication repeater system includes a master station device, slave station devices, radio frequency units that convert signals from base station systems into optical digital signals for transmission to the master station device. The base station systems establish communication by time-division duplex scheme. The communication repeater system repeats communication between a mobile communication terminal device and each base station system via a corresponding slave station device. At least one of the radio frequency units and the master and slave station devices includes a learning-signal input port, and a setter that generates a reference transmission/reception switching timing signal based on a learning signal input to the learning-signal input port and sets the generated signal as reference transmission/reception switching timing. The rest of the units and the devices each include a corrector that corrects variation in transmission/reception switching timing according to the reference transmission/reception switching timing.

An apparatus comprising a bidirectional amplifier or node supporting out-of-band signaling may be provided. The apparatus may comprise a first diplexer, a second diplexer, an upstream reverse amplifier, and a downstream Out-of-Band (OOB) amplifier. The first diplexer may comprise a first diplexer band-stop filter and a first diplexer band-pass filter. The first diplexer band-stop filter may be connected between a first diplexer first port and a first diplexer second port. The first diplexer band-pass filter may be connected between the first diplexer first port and a first diplexer third port. The second diplexer may comprise a second diplexer band-stop filter and a second diplexer band-pass filter. The second diplexer band-stop filter may be connected between a second diplexer first port and a second diplexer second port. The second diplexer band-pass filter may be connected between the second diplexer first port and a second diplexer third port.

An apparatus comprising a bidirectional amplifier or node supporting out-of-band signaling may be provided. The apparatus may comprise a first diplexer, a second diplexer, an upstream reverse amplifier, and a downstream Out-of-Band (OOB) amplifier. The first diplexer may comprise a first diplexer band-stop filter and a first diplexer band-pass filter. The first diplexer band-stop filter may be connected between a first diplexer first port and a first diplexer second port. The first diplexer band-pass filter may be connected between the first diplexer first port and a first diplexer third port. The second diplexer may comprise a second diplexer band-stop filter and a second diplexer band-pass filter. The second diplexer band-stop filter may be connected between a second diplexer first port and a second diplexer second port. The second diplexer band-pass filter may be connected between the second diplexer first port and a second diplexer third port.