WDM up-conversion employing frequency quadrupling in optical modulator

Abstract

This work presents an optical up-conversion system with frequency quadrupling for wavelength-division-multiplexing (WDM) communication systems using a dual-parallel Mach-Zehnder modulator without optical filtering. Four-channel 1.25-Gb/s wired fiber-to-the-x (FTTx) and wireless radio-over-fiber (RoF) signals are generated and transmitted simultaneously. Moreover, the decline in receiver sensitivities due to Mach-Zehnder modulator bias drifts is also investigated. Receiver power penalties of the 20-GHz up-converted WDM signals and baseband (BB) FTTx signals are less than 1 dB when bias deviation voltage is less the 20% of the half-wave voltage. After transmission over a 50-km SSMF, the receiver power penalties of both the BB and 20-GHz RF OOK signals are less than 1 dB. Notably, 60-GHz optical up-conversion can be achieved using 15-GHz radio frequency (RF) components and equipment.

Studies in an optical millimeter-wave generation scheme via two parallel dual-parallel Mach–Zehnder modulators

“…All of the sub-MZMs have the same switching voltage or half-wave voltage V , and the phase differences between two arms of a sub-MZM introduced by a DC bias are 0 , 1 , 2 and 3 , respectively, where i ¼ V dci =V , V dci is the DC bias for each sub-MZM (i ¼ 0, 1, 2, 3). Note that there is no filter and the like in this scheme, so it can also be readily used in a WDM system [9,17].…”

Photonic generation and radio transmission of ECMA 387 signal at 60 GHz using WDM demultiplexer

“…In Ref. 3, a complex dual parallel Mach–Zehnder modulator (MZM) working as a frequency quadrupling is used to generate broadband mmW, however only radio frequency (RF) on‐off‐keying (OOK) modulation scheme can be implemented by this system, and radio propagation is not demonstrated. To address different users in a mmW RoF multiple access system, it is interesting to apply wavelength division multiplexing (WDM) technique.…”

Transmission of 20-Gb/s OFDM signals occupying 7-GHz license-free band at 60 GHz using a RoF system employing frequency sextupling optical up-conversion

“…This RoF system is capable of transmitting radio signals with high spectral efficiency, such as M-arry phase-shift keying (M-PSK), quadrature-amplitudemodulation (QAM), and orthogonal frequency-division multiplexing (OFDM) signals. Furthermore, based on the wavelength independent optical up-conversion system, wavelength-division-multiplexed multiplexing (WDM) up-conversion can be achieved [10]. A 13.75-Gb/s quadrature-phase-shift-keying OFDM (QPSK-OFDM) signal and a 20.625-Gb/s 8QAM-OFDM signal are employed to experimentally demonstrate the system capability.…”

“…Notably, frequency doubling is achieved after the first stage. The second stage is an optical up-conversion system which is composed of a wavelengthindependent optical MMW generation system with frequency quadrupling using another DP-MZM [10] along with an optical interleaver. After the optical up-conversion of the MMW generation system, both the un-modulated and data modulated optical sidebands are upconverted with frequency four times that of the up-conversion system driving signal, as shown in inset (ii) of Fig.…”