Abstract: This application relates to monomers of the general formula (I) for the preparation of PNA (peptide nucleic acid) oligomers and provides method for the synthesis of both predefined sequence PNA oligomers and random sequence PNA oligomers: wherein R1, R2, R3, R4, R5 is independently H, halogen, C1–C4 alkyl, nitro, nitrile, C1–C4 alkoxy, halogenated C1–C4 alkyl, or halogenated C1–C4 alkoxy, wherein at least one of R1, R3, and R5 is nitro; R6 is H or protected or unprotected side chain of natural or unnatural ?-amino acid; and B is a natural or unnatural nucleobase, wherein when said nucleobase has an exocyclic amino function, said function is protected by protecting group which is labile to acids but stable to weak to medium bases.

Abstract: A passive optical network using downstream and upstream optical signals for achieving a two-way communication is provided, wherein the downstream and upstream optical signals have different polarization components and an equal wavelength band.

Abstract: This application relates to monomers of the general formula (I) for the preparation of PNA (peptide nucleic acid) oligomers and provides method for the synthesis of both predefined sequence PNA oligomers and random sequence PNA oligomers: wherein E is nitrogen or C—R?; J is sulfur or oxygen; R?, R1, R2, R3, R4 is independently H, halogen, alkyl, nitro, nitrile, alkoxy, halogenated alkyl, halogenated alkoxy, phenyl or halogenated phenyl, R5 is H or protected or unprotected side chain of natural or unnatural ?-amino acid; and B is a natural or unnatural nucleobase, wherein when said nucleobase has an exocyclic amino function, said function is protected by protecting group which is labile to acids but stable to weak to medium bases in the presence of thiol.

Abstract: An optical duo-binary transmission apparatus using a duo-binary modulation method is disclosed. The optical duo-binary transmission apparatus using a polarization modulator includes a precoder for coding an inputted binary data signal; a low-pass filter for converting the coded binary data signal into a three-level signal by restricting a bandwidth of the coded binary data signal; a light source for generating light; a polarization modulator for modulating a polarization of the light outputted from the light source according to the three-level signal; and a polarizer for transmitting only an optical signal having a predetermined directionality from among polarization-modulated optical signals.

Abstract: A bi-directional add/drop node employed in a bi-directional path-switching network linked by an optical fiber in a loop form is disclosed. The bi-directional add/drop node has a first terminal point and a second terminal point for receiving channels over the optical fiber such that odd channels are inputted through the first terminal point are outputted through the second terminal point and even channels are inputted through the second terminal point are outputted through the first terminal point.

Abstract: An optical duo-binary transmission apparatus using an optical duo-binary transmission method is disclosed. The apparatus includes a duo-binary encoder that performs parallel processing. The duo-binary encoder includes a level change detection unit for detecting that levels of data input signals of N channels input at an nth input of channels change from 0 to 1, or from 1 to 0; a judgment unit for judging whether a number of level changes detected by the level change detection unit is odd or even; and a toggle unit for toggling an output signal of the judgment unit when the number of level change is odd.

Abstract: An optical duo-binary transmission apparatus using an optical duo-binary transmission method is disclosed. The apparatus includes a duo-binary encoder that performs parallel processing. The duo-binary encoder includes a level change detection unit for detecting that levels of data input signals of N channels input at an nth input of channels change from 0 to 1, or from 1 to 0; a judgment unit for judging whether a number of level changes detected by the level change detection unit is odd or even; and a toggle unit for toggling an output signal of the judgment unit when the number of level change is odd.

Abstract: An EML transmitter having a band stop filter to improve the transmission characteristics before and after the transmission is provided. This is achieved by improving the chirp characteristics and the extinction ratio during the transmission of optical signals using an EML. The inventive EML transmitter includes: an EML for generating transmission light; a first lens for focusing optical signal outputs from the EML to prevent loss of the optical signals; a second lens for focusing the optical signals into a core portion of an optical line; and, a band stop filter for removing the D.C. component from the optical signals outputted by the EML.

Abstract: A precoder for an optical duo-binary transmission apparatus disposing the precoder before a time division multiplexer includes a judgment unit for judging whether an odd number or even number of ‘1’s exist in data input signals of N channels inputted at an nth time of channel input. Further included in the precoder is a toggle unit for toggling an output signal of the judgment unit when the judgment is odd, and for determining an output value for one of the channels. The precoder also has an output unit for determining output values of other channels according to a respective data input signal and a predetermined channel from among the N channels.

Abstract: A duobinary optical transmission device that uses a duobinary optical transmission technique is disclosed. The duobinary optical transmission device may use an X-cut Mach-Zehnder interferometer type modulator. The duobinary optical transmission device includes a light source that outputs a carrier wave. A duobinary encoder encodes an input non-return-to-zero (NRZ) electrical signal. A low pass filter (LPF) converts the encoded signal into a 3-level electrical signal. An optical intensity modulator modulates the phase and light intensity of the carrier wave according to the 3-level electrical signal and outputs a 2-level optical duobinary signal. The optical intensity modulator may be an X-cut optical intensity modulator including a substrate; an optical waveguide formed on the substrate, and an electrode for applying an electric field.

Abstract: A duo-binary encoder performs a parallel processing and an optical duo-binary transmission apparatus using the encoder to enhance transmission capability. The duo-binary encoder has a judgment unit for judging whether an odd number or even number of ‘0’s exists in data input signals of N channels, a toggle unit for toggling an output signal of the judgment unit when a number of ‘0’s is even, an intermediate signal generation unit for determining whether phases of other channels are shifted or not, according to an data input signal on the basis of a predetermined channel of the N channels. A phase division unit divides data into a first data group having non-shifted phases and a second group of data that require a phase shift, according to an output signal of the intermediate signal generation unit and the data input signal. The divided first and second data groups are then output.

Abstract: Disclosed is a duobinary optical transmission apparatus using a semiconductor optical amplifier (SOA). The duobinary optical transmission apparatus includes a light source for generating a carrier wave; a duobinary precoder for encoding an input (non return to zero) electric signal; a semiconductor optical amplification unit to amplify the encoded signal from the duobinary precoder, wherein the amplification unit receives an optical amplification gain difference that varies with a bias current combined with the encoded signal; and an optical band pass filter for receiving a phase-modulated optical signal from the semiconductor optical amplification unit, filtering the received optical signal to a prescribed bandwidth, and thereby generates a duobinary optical signal.

Abstract: A duobinary optical transmission apparatus has a characteristic of phase intersection without using an existing feedback-type precoder and an electrical low-pass filter, thereby eliminating the influence by pseudo random bit sequence. The invention realizes a transmission system having increased immunity against dispersion of an optical fiber, and thus can increase transmission distance and transmission speed of an optical signal. The duobinary optical transmission apparatus includes: a light source outputting an optical carrier; an NRZ optical signal generating section receiving an NRZ electrical signal, modulating the optical carrier into an NRZ optical signal according to the NRZ electrical signal, and outputting the NRZ optical signal; and a duobinary optical signal generating section receiving the NRZ electrical signal and modulating the NRZ optical signal into a duobinary optical signal.

Abstract: An EML transmitter having a band stop filter to improve the transmission characteristics before and after the transmission is provided. This is achieved by improving the chirp characteristics and the extinction ratio during the transmission of optical signals using an EML. The inventive EML transmitter includes: an EML for generating transmission light; a first lens for focusing optical signal outputs from the EML to prevent loss of the optical signals; a second lens for focusing the optical signals into a core portion of an optical line; and, a band stop filter for removing the D.C. component from the optical signals outputted by the EML.

Abstract: A bi-directional path switched ring optical transmission node has a simple configuration which reduces the influence of a wave reflected by an obstacle on optical line. The BPSR optical transmission node connects to a first optical line through which an odd channel signal and an even channel signal are transmitted to and from the BPSR optical transmission node in directions opposite to each other. The BPSR optical transmission node further connects to a second optical line through which the odd channel signal and the even channel signal are transmitted from and to the BPSR optical transmission node in directions opposite to each other.

Abstract: An optical CRZ transmitter using a Mach-Zehnder (MZ) modulator is provided which enables a simple construction process and has reduced production cost. The optical CRZ transmitter includes a logic operation unit for performing a logic operation between a received NRZ (Non Return-to-Zero) data signal and clock signal data signal and a clock signal, and generating electric RZ (Return-to-Zero) data; an amplifier to amplify the electric RZ data; and a MZ modulation unit to modulate the amplified electric RZ data into an optical signal, and impose a chirp signal on the optical signal by varying an input voltage of the amplified electric RZ data.

Abstract: Disclosed is a duobinary optical transmission apparatus. The duobinary optical transmission apparatus uses the crossed phase characteristics of a duobinary signal without using a feedback-type precoder and an electric LPF, and is thereby not affected by Pseudo-Random Bit Sequence (PRBS), and is very resistant to wavelength division characteristics. In addition to a drive amplifier, a Mach-Zehnder-interferometer-type optical intensity modulator (MZ MOD), and a laser source for generating a carrier wave, the duobinary optical transmission apparatus further includes a toggle flip-flop (T.FF) and an AND gate to separate a group of ‘1’ from input data signal in such a way that the input data signal is modulated to make each signal have a different phase.

Abstract: A duobinary optical transmission apparatus is disclosed using a duobinary optical transmission technique. The apparatus has increased immunity against dispersion and non-linearity in high-speed long-distance wavelength division multiplexing (WDM) transmission of an optical signal, without using an electrical low-pass filter. The duobinary optical transmission apparatus includes a light source outputting an optical carrier; an NRZ optical signal generating section receiving an NRZ electrical signal, modulating the optical carrier into an NRZ optical signal according to the NRZ electrical signal, and outputting the NRZ optical signal, and a duobinary optical signal generating section receiving the NRZ electrical signal and modulating the NRZ optical signal into a duobinary optical signal.

Abstract: This application relates to monomers of the general formula (I) for the preparation of PNA (peptide nucleic acid) oligomers and provides method for the synthesis of both predefined sequence PNA oligomers and random sequence PNA oligomers: 1

Abstract: This application relates to monomers of the general formula (I) for the preparation of PNA (peptide nucleic acid) oligomers and provides method for the synthesis of both predefined sequence PNA oligomers and random sequence PNA oligomers: 1