A novel scheme for the optical generation and coherent detection of tunable narrow-band far-infrared radiation in free space is described. This technique involves the optical heterodyning of two linearly chirped broadband pulses to produce a quasi-sinusoidal intensity modulation at tunable terahertz frequencies. The frequency content of the narrow-band terahertz radiation produced by mixing chi...

There are many modulation methods suitable for optical wireless communication. OOK, PPM are adopted widely in optical wireless communication for its high average-power-efficiency. DPPM, DPIM and DH-PIM are three new modulation methods for optical wireless communication, which may be the substitutes of PPM because of their better performance in power efficiency and bandwidth efficiency. In this ...

We propose a technique for timing an XFEL to a highpower laser with femtosecond accuracy. The same electron bunch is used to produce an XFEL pulse and an ultrashort optical pulse that are, thus, naturally synchronized. Cross-correlation techniques will yield the relative jitter between the optical pulse (and, thus, the XFEL pulse) and a pulse from an external pump-laser with femtosecond resolut...

A terahertz-wave communication system directly connected to an optical fiber network is promising for application to future mobile backhaul and fronthaul links. The possible broad bandwidth in the terahertz band is useful for high-speed signal transmission as well as radio-space encapsulation to the high-frequency carrier. In both cases, the low-latency feature becomes important to enhance the ...

This article overviews optical wireless communications using multiple-subcarrier modulation (MSM). The basic principles and characteristics of the optical wireless communications using MSM are presented. The optical wireless systems using MSM are explained where some block codes that convert information bits to be transmitted to the symbol amplitudes of subcarriers are used to increase the mini...

All-optical code conversion of 10 Gb/s BPSK codes without wavelength-shift by use of cross-phase modulation in an optical fiber for optical code division multiplexing networks is proposed and experimentally demonstrated.

The electronic layer multicast is going to face the speed and capacity bottleneck of the future optical data networks. Transparent optical wavelength multicast by multi-wavelength conversion is an effective way of achieving data multicast in the optical domain without any optical-electronic-optical conversion. In this paper, two multiple wavelength conversion technologies for 10 Gb/s data rate ...

There are many modulation methods suitable for optical wireless communication. OOK, PPM are adopted widely in optical wireless communication for its high average-power-efficiency. DPPM, DPIM and DH-PIM are three new modulation methods for optical wireless communication, which may be the substitutes of PPM because of their better performance in power efficiency and bandwidth efficiency. In this ...

Today's high-capacity telecommunication systems are unimaginable without the use of optical fibres and accompanying optical components which are briefly presented in this paper with an accent on the receivers of optical signal. An overview of main characteristics of the key elements and the description of the most popular modulation formats in modern optical systems is shown. Some achievements ...