71 results about "Reflective semiconductor optical amplifier" patented technology

Disclosed herein is a loop-back Wavelength Division Multiplexing Passive Optical network (WDM-PON). The loop-back WDM-PON includes a coupler, a terminal receiver, and a reflective semiconductor amplifier. The coupler branches a downstream signal, which is transmitted from a central office, into first and second downstream signals. The terminal receiver receives and converts the first downstream signal into electrical signal and provides the electrical signal to a subscriber. The reflective semiconductor optical amplifier flattens modulated optical power of the second downstream signal input to the RSOA and re-modulating the flattened signal by changing driving current in response to upstream data.

Disclosed herein is an optical access network system in which the transmission quality of an upstream signal is remarkably improved in an optical access network in which a Reflective Semiconductor Optical Amplifier (RSOA) is used as the light source for each subscriber. The most important characteristics of the present invention are that a Manchester modulation format is used as a modulation format for a downstream signal in an optical access network system in which an RSOA is used as the light source for each subscriber, so that the problem of deterioration of the transmission quality of a remodulated upstream signal, occurring when an RSOA is used as the light source for each subscriber, is solved, and thus the transmission performance of an upstream signal and the power budget performance of the entire system are improved. According to the present invention, an RSOA-based WDM PON system, in which performance at a power budget and the transmission performance of a remodulated upstream signal are improved, can be implemented.

Provided is a passive optical network (PON) based on a reflective semiconductor optical amplifier (RSOA). In the PON, seed-light-injection RSOAs are used in an optical line terminal (OLT) to achieve the color-less management of the wavelengths of OLT optic sources, and wavelength reuse RSOAs are used to achieve the color-less management of the wavelengths of ONTs. Therefore, problems related to ONT wavelength management can be eliminated by the wavelength reuse RSOAs, and problems related to OLT wavelength management can be eliminated by the seed-light-injection RSOAs.

A Reflective Semiconductor Optical Amplifier (RSOA) for compensating for light loss in an optical link, an RSOA module for improving polarization dependency using the RSOA, and a Passive Optical Network (PON) for increasing economical efficiency and practical use of a bandwidth using the RSOA are provided. The PON includes a central office comprising a plurality of optic sources transmitting a downstream signal and a plurality of first receivers receiving an upstream signal; at least one optical network terminal (ONT) including a second receiver receiving the downstream signal and an RSOA which receives the downstream signal, remodulates the downstream signal into the upstream signal, and transmits the upstream signal in loopback mode; and a remote node interfacing the central office with the ONT. The upstream signal and the downstream signal are transmitted between the remote node and the ONT via a single optical fiber. The remote node includes an optical power splitter at its port connected to the ONT.

Provided are a wavelength division multiplexing-passive optical network (WDM-PON) in which a reflective semi-conductor optical amplifier (RSOA) is used as each optical transmitter of an optical line termination (OLT) and an optical network unit (ONU) and additional spectrum-sliced light is injected into RSOAs of each of the OLT and the ONU, and a WDM-PON that is combined with time division multiple access (TDMA) technology, by which the number of included ONUs increases and conventional TDMA ONUs can be used.

Provided are a reflective semiconductor optical amplifier (R-SOA) and a superluminescent diode (SLD). The R-SOA includes: a substrate; an optical waveguide including a lower clad layer, an active layer independent of the polarization of light, and an upper clad layer sequentially stacked on the substrate, the optical waveguide comprising linear, curved, and tapered waveguide areas; and a current blocking layer formed around the optical waveguide to block a flow of current out of the active layer, wherein the linear and curved waveguide areas have a single buried hetero (BH) structure, and the tapered waveguide area has a dual BH structure.

The invention relates to a system and a method for leading a wavelength division multiplexing passive optical network to realize the broadcast function with the self-healing function. The system adopts 1 optical line terminal OLT which is connected with a remote node RN through two single-mode optical fibers, and the remote node RN is connected with N-1 optical network units ONU, wherein the remote node RN mainly consists of 2 optical fiber Bragg gratings FBG, two 1 multiplied by (N-1) star couplers and 1 N multiplied by N AWG; broadcast signals sharing wavelength are reflected back by the optical fiber Bragg gratings FBG, divided by the 1 multiplied by (N-1) star couplers and then sent to N-1 input ports of an arrayed waveguide grating AWG; the transmission of the broadcast signals and point-to-point signals can be realized through the properties of the arrayed waveguide grating AWG; symmetric structures are adopted at two ends of the N multiplied N AWG for realizing the self-healing function of the system; and the transmission of the point-to-point uplink signals in the system is realized by utilizing the remodulation technology of a reflective semiconductor optical amplifier RSOA. The scheme can realize the transmission of the broadcast signals by only changing the structure of the system, and further balance the cost and the performances of the system.

Disclosed is a passive optical network comprising a central office including a plurality of first reflective semiconductor optical amplifiers of a quantum-dot type, each of which generates a wavelength-seeded downstream optical signal on a downstream channel of a corresponding wavelength, a plurality of optical network units each of which includes a second reflective semiconductor optical amplifier of a multi-quantum-well type, the second reflective semiconductor optical amplifier generating a wavelength-seeded upstream optical signal on an upstream channel of a corresponding wavelength and a remote node for outputting the downstream optical signals to corresponding optical network units, and multiplexing and outputting the upstream optical signals to the central office.

A reflective semiconductor optical amplifier (RSOA) and an operating system based on a downstream optical signal reuse method with feed-forward current injection are provided. The RSOA has two active regions and includes a reflecting plane that reflects an input optical signal; and an optical amplifying semiconductor including a rear portion, which is positioned at a side of the reflecting plane and to which a signal having polarity opposite to that of the input optical signal is injected, and a front portion, which is positioned at a side opposite to the side of the rear portion facing the reflecting plane and which the input optical signal is passed though and a signal used to modulate a reflected input optical signal from the reflecting plane to an output optical signal is injected into.

A reflective semiconductor optical amplifier light source is disclosed. The reflective semiconductor optical amplifier light source includes a transmissive type semiconductor optical amplifier for creating and amplifying spontaneous emission light, a reflector for reflecting amplified spontaneous emission light outputted from the semiconductor optical amplifier such that amplified spontaneous emission light is reflected back into the semiconductor optical amplifier, and a bandpass filter having a predetermined wavelength band width for limiting wavelength bands of the amplified spontaneous emission light capable of passing through the bandpass filter. In one aspect of the invention, the bandpass filter is interposed between the semiconductor optical amplifier and the reflector. In another aspect, a polarization filter is imposed to limit the reflected emission light to a predetermined polarization.

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.

The invention discloses a centralized protection passive optical network system based on an optical carrier suppression technology. The centralized protection passive optical network system comprises an optical line terminal, working feed-in fibers, protection feed-in fibers, a far-end node, N working distributed fibers, N protection distributed fibers and N optical network units. The optical line terminal comprises a carrier suppression double-sideband signal transmitter, a first comb filter, a 1*2 optical switch, a first array waveguide grating, an upper link and down link data transceiver, a second array waveguide grating, an erbium doped fiber amplifier, a second comb filter and a monitoring and control unit. The far-end node comprises a third array waveguide grating and a fourth array waveguide grating. Each optical network unit comprises a 2*2 optical coupler, a down link receiver and a reflective semiconductor optical amplifier.

An optical receiver is provided which can be applied to a wavelength division multiplexing passive optical network (WDM PON) based on a reflective semiconductor optical amplifier employing a wavelength reuse scheme. The optical receiver includes a photo diode to convert an optical signal to an electrical signal; a pre-amplifier to linearly amplify the electrical signal and convert the amplified electrical signal to a voltage signal; a post-amplifier, which is equipped with a gain control function, to convert the voltage signal to a signal with a constant output level and to control a decision threshold of the converted signal; and an offset voltage generator to generate a predetermined offset voltage for the decision threshold control of the post-amplifier and to provide the offset voltage to the post-amplifier. Accordingly, it is possible to increase an extinction ratio of a downstream optical signal to a predetermined level in the WDM PON based on a reflective semiconductor optical amplifier employing a wavelength reuse scheme, and it is possible to reduce an optical power, which is received by the reflective semiconductor optical amplifier incorporated in a subscriber terminal, below a predetermined level. As a result, it is possible to improve transmission quality of the downstream and upstream optical signals.

The invention discloses a wavelength-tunable directly modulated silicon-based external cavity laser. A reflective semiconductor optical amplifier of the directly modulated external cavity laser is connected to a phase shifter through a silicon-based spot size converter and then is connected to an input end of a narrow passband filter; an output end of the narrow passband filter is connected to theinput end of a micro-ring modulator; a download end of the micro-ring modulator is connected to the input end of a first reflector; and a through end of the micro-ring modulator is connected to a second reflector. According to the wavelength-tunable directly modulated silicon-based external cavity laser, a filter structure is formed through cursor effects of the narrow passband filter and the micro-ring modulator to obtain laser light with a wide tuning range and a narrow linewidth, and meanwhile, output light is modulated. The micro-ring modulator has dual functions of filtering and modulating and has the advantages of high structure integration, low manufacturing cost and low energy consumption.

A wavelength-tunable directly modulated fiber ring laser is provided. Generally speaking, the wavelength-tunable directly modulated fiber ring laser employs an RSOA (reflective semiconductor optical amplifier) and an OTF (optical tunable filter) to construct a novel ring resonant cavity. Additionally, a signal generator can be further employed to transmit modulated signals to the RSOA, whereby generating light wave with the modulated signals, so as to provide tunable wave-length and direct modulation at the same time.

The invention discloses a system and a method for realizing low-cost local area network service transmission for a wavelength division multiplexing optical access network. According to the system, an optical line terminal (OLT) is connected with a remote node RN through a feeder line optical fiber to form a tree-shaped network; the remote node RN is connected with an optical network unit ONU through a distributed optical fiber; the optical line terminal comprises N optical signal transmitters, N distributed feedback lasers DFB, N optical signal receivers, three 1*N array waveguide gratings AWG, a phase modulator PM, three optical circulators, a coarse wavelength division multiplexer, a waveband block WB, an optical isolator, N*N array waveguide gratings AWG and N optical network units ONU; each optical network unit ONU comprises two coarse wavelength division multiplexers, an optical circulator, an optical divider, three optical signal receivers, a reflective semiconductor optical amplifier RSOA, an electro absorption modulator EAM and a wideband light source BLS. Through the structural design of the RN end array waveguide gratings and the ONU end wideband light source, high-speed transmission of low-cost local area network service can be effectively realized in the wavelength division multiplexing optical access network (WDM-OAN).

The invention relates to a wavelength division multiplexing passive optical network optical fiber link distributed protection device. An optical line terminal is connected with a remote node through a working feed-in optical fiber and a protection feed-in optical fiber. N de-multiplexing ports of the remote node are respectively connected with N working distributed optical fibers, and the N de-multiplexing ports are respectively connected with N protection distributed optical fibers. Each optical network unit comprises a monitoring and control unit, a first optical coupler, a downlink receiver, and a reflective semiconductor optical amplifier. Each monitoring and control unit comprises an optical power detector and an optical switch. The N working distributed optical fibers and the N protection distributed optical fibers are connected with the reflective semiconductor optical amplifiers and the downlink receivers through the monitoring and control units via the first optical couplers respectively. According to the invention, a colorless optical distribution network is realized, the use of an independent light source is avoided, the complexity and cost of equipment are reduced, and unlink and downlink services of other users are not affected during protection of switching protection.

A tunable laser comprises a reflective semiconductor optical amplifier (SOA), a grating co-directional coupler and a reflective micro-ring resonator, and the grating co-directional coupler and the reflective micro-ring resonator are both formed on a silicon substrate. A first end face of the reflective SOA is provided with an anti-reflection film, and the first end face is an end face where the reflective SOA is coupled with a first waveguide of the grating co-directional coupler. A second waveguide of the grating co-directional coupler is coupled with the first waveguide, the first waveguideis provided with a first grating, the second waveguide is provided with a second grating opposite to the first grating, and the first grating and the second grating form a narrow-band filter, and thesecond waveguide is connected with the reflective micro-ring resonator. The tunable laser has the advantages that wavelength tuning is easier, and the wavelength tuning speed is higher.

The invention discloses a high-speed and high-linearity silicon-lithium niobate external cavity frequency modulation laser. A reflective semiconductor optical amplifier of the external cavity laser isconnected to a phase shifter through a silicon-based light spot size converter; and then the output end of the phase shifter is connected with the input end of the first micro-ring filter, the outputend of the first micro-ring filter is connected with the input end of the second micro-ring filter, and the output end of the second micro-ring filter is connected with the input end of the reflector. And a lithium niobate film is bonded above the silicon waveguide. According to the invention, a filtering structure is formed through vernier effects of the two micro-ring filters, and laser with awide tuning range and a narrow line width can be obtained. By utilizing the advantages of low loss, strong linear electro-optic effect and high modulation speed of the lithium niobate film, the line width of the laser can be further compressed, the output laser power is improved, and high-speed linear frequency modulation is realized.

The invention discloses a fiber bragg grating (FBG) sensing demodulation device based on a reflective semiconductor optical amplifier (RSOA). The FBG sensing demodulation device comprises a tunable laser, an optical circulator, a photoelectric detector and a processing and control unit, wherein the tunable laser comprises the RSOA, an optical coupler and a tunable FBG unit in sequential connection. The invention also discloses an FBG sensing demodulation method based on the RSOA. The sensing demodulation device and the sensing demodulation method realize the FBG sensing demodulation with the advantages of high speed, low cost and simple structure.