摘要:
A TDM PON including: an optical line terminal; a remote node including multiple secondary optical distributors connected to multiple optical network units; and the multiple optical network units generating and outputting a corresponding upstream optical signal. Each of the secondary optical distributors splits an upstream optical signal input from one of the optical network units connected thereto so as to generate split upstream optical signals and transmits one of the upstream optical signals to the optical line terminal, and transmits another upstream optical signal to a different optical network unit.
摘要:
Disclosed is a subcarrier multiplexing type optical communication method including the steps of receiving a first optical signal composed of a plurality of subcarrier channels having different frequencies, creating a second optical signal having a wavelength different from a wavelength of a received signal; and detecting the subcarrier channels from a third optical signal obtained by subjecting the first optical signal to wavelength shift by means of the second optical signal.
摘要:
Disclosed is a method for maintaining wavelength-locking of a Fabry-Perot laser regardless of a change of external temperature even though a temperature controller is not used, and a wavelength division multiplexing (WDM) light source using the method, as an economical light source used in a WDM optical communication field. The WDM light source comprises a Fabry-Perot laser for injecting spectrum-spliced incoherent light to amplify and output only an oscillation mode matching with a wavelength of the injected light, and a bias controlling unit for adjusting a bias current supplied to the Fabry-Perot laser to a value adjacent to a threshold current of the Fabry-Perot laser, whose threshold current is changed according to a temperature and a relationship between the injected light changed depending to a temperature and a wavelength of the oscillation mode. Therefore, the bias current having a value adjacent to the threshold current of the Fabry-Perot laser is supplied to the Fabry-Perot laser, so that the Fabry-Perot laser can maintain an excellent transmission characteristic regardless of a change of temperature even though a temperature controller is not used.
摘要:
A wavelength-division-multiplexed light source for transmitting broadband light through a fiber and receiving an optical signal through the fiber is disclosed. The wavelength-division-multiplexed light source includes: a light source for outputting broadband light; and a coupler for outputting the broadband light, which has been input from the light source, to the fiber through cross coupling, and outputting an optical signal, which has been input from the fiber, through bar coupling, based on a predetermined cross coupling ratio, wherein the cross coupling ratio of the coupler is adjusted depending on a power of the optical signal.
摘要:
A SCM-PON using WDM includes: an OLT for transferring downstream data from an external service provider through downstream optical signals and transferring upstream data transferred through upstream optical signals to an outside; an ODN for distributing the downstream optical signals from the OLT and multiplexing the upstream optical signals to the OLT; and a plurality of ONUs for processing the downstream optical signals transferred from the OLT through the ODN and transferring upstream data of subscribers for the OLT through the upstream optical signals, wherein the optical signals between the OLT and the ONUs are divided into wavelength channels with different wavelengths and sub-carrier channels obtained by time-dividing the wavelength channels, and the upstream data and the downstream data are transferred through the sub-carrier channels.
摘要:
An economical wavelength-division-multiplexed passive optical network (WDM-PON) system is realized by directly modulating a wavelength-seeded light source to transmit upstream or downstream data, without using an expensive external modulator. A multiplexed signal having the same wavelength as the waveguide grating is generated and used to control the temperature of the waveguide grating and adjust the wavelength of a wavelength-division-multiplexed signal routed to a transfer link. The wavelength selectivity and stabilization of each light source are not required. Since upstream and downstream signals can be multiplexed and demultiplexed concurrently by each waveguide grating located in the central office and the remote node, it is possible to reduce the number of waveguide gratings used in a WDM optical network. In addition, upstream and downstream signals can be transmitted concurrently using a single-strand transfer optical fiber, thereby realizing an economical and efficient WDM-PON.
摘要:
A bi-directional WDM-PON and a method for allocating a wavelength band are disclosed. In the bi-directional WDM-PON, bi-directional transceiver modules are used to transmit optical signals of different wavelengths in the upstream and downstream directions. An L-band and an S-band are used to allocate wavelength bands to the upstream and downstream optical signals so that a wavelength band interval at which the respective wavelength bands of the upstream and downstream optical signals are spaced is set between 50 nm to 150 nm.
摘要:
A wavelength-division-multiplexed passive optical network using an economical multi-wavelength lasing source and a reflective optical amplification device is disclosed. The wavelength-division-multiplexed passive optical network includes a central office in which a multi-wavelength lasing source is located; a plurality of subscriber terminals for transmitting an upward signal by a refection signal of a multi-wavelength signal transmitted from the central office; and a local office, which is connected among the central office and the subscriber terminals through transmission optical fibers, for demultiplexing the multi-wavelength signal transmitted from the central office and transmitting the demultiplexed signal to the subscriber terminals, and for multiplexing signals inputted from each of the subscriber terminals and transmitting the multiplexed signals to the central office.
摘要:
A WDM (Wavelength Division Multiplexing) optical transmitter using a Fabry-Perot laser is disclosed. The WDM optical transmitter includes a light source for outputting incoherent light of a prescribed wavelength bandwidth, a circulator having the first to the third ports, for outputting the incoherent light received at the first port coupled to the light source to the second port, and outputting an optical signal received at the second port to the third port coupled to the external waveguide, a WGR (Waveguide Grating Router) having a multiplexing port (MP) coupled to the second port of the circulator and a plurality of demultiplexing ports (DPs), for performing WD (Wavelength Division) demultiplexing on the incoherent light received at the MP to output WD-demultiplexed signals to the plurality of DPs, and performing WD multiplexing on a plurality of channel signals received at the plurality of DPs to output WD-multiplexed signals to the MP, and a plurality of FB (Fabry-Perot) lasers respectively connected to the DPs of the WGR, each FP laser is comprised of a laser cavity, an antireflection coating layer deposited at one end of the laser cavity facing a corresponding DP, and a high reflection coating layer deposited at the other end of the laser cavity, whereby an optical injection efficiency increases and an influence of reflected light is reduced, resulting in facilitation of a wavelength-locked phenomenon.
摘要:
An optical wavelength tracking apparatus and method in a wavelength division multiplexed (WDM) passive optical network (PON) in which a central office (CO) having a multi-frequency light source is connected to a plurality of optical network units (ONUs) having loop-back light sources through a WDM MUX/DEMUX in a remote node (RN). The power levels of downstream and upstream WDM optical signals are measured. The WDM wavelengths of the multi-frequency light source and the WDM MUX/DEMUX are controlled to be nearly identical in order to minimize the difference between the power levels of the downstream and upstream WDM optical signals.