We propose and demonstrate an optical minimum-shift-keying (MSK) transmitter using a single-quad Mach-Zehnder (MZ) in-phase and quadrature modulator, where four sub-Mach-Zehnder modulators are monolithically integrated on a main MZ superstructure. Using the proposed transmitter, a MSK signal at bit rate of B could be successfully generated by orthogonally superposing two low-speed (B/2) carrier-suppressed return-to-zero differential phase-shift-keying streams with a relative time offset, 1/B. MSK signals at bit rate of 20 and 80 Gbits/s were successfully generated using the proposed MSK transmitter. A continuous changed phase trajectory of the obtained MSK was confirmed using a complex spectrum analyzer. The filtering tolerance of the MSK was also characterized using a bandwidth-variable tunable filter.
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http://dx.doi.org/10.1364/OL.34.002144 | DOI Listing |
Although free space optical (FSO) communication is a promising technique for deep space communication and it can help in the rapid development of space exploration missions, it encounters coronal turbulence during superior solar conjunction. To improve the bit error rate (BER) performance of FSO communication system under the influence of coronal turbulence, a hybrid modulation scheme, L-PPM-MSK-SIM-which is a combination of pulse position modulation (PPM), minimum shift keying (MSK), and sub-carrier intensity modulation (SIM) techniques-is proposed in this study. Considering various noise sources, both the BER and channel capacity of the communication system are evaluated under the lognormal (LN) turbulence channel.
View Article and Find Full Text PDFMinimum shift keying (MSK) has been widely used in fiber optical communication and free-space optical communication. In order to introduce MSK into satellite laser communication, the bit-error rate (BER) performance of the MSK scheme is investigated in uplink communications under the influence of atmospheric turbulence consisting of weak fluctuation and beam wander. Numerical results indicate that the BER performance of MSK is much better than the performance of on-off keying (OOK).
View Article and Find Full Text PDFWe propose and demonstrate an optical minimum-shift-keying (MSK) transmitter using a single-quad Mach-Zehnder (MZ) in-phase and quadrature modulator, where four sub-Mach-Zehnder modulators are monolithically integrated on a main MZ superstructure. Using the proposed transmitter, a MSK signal at bit rate of B could be successfully generated by orthogonally superposing two low-speed (B/2) carrier-suppressed return-to-zero differential phase-shift-keying streams with a relative time offset, 1/B. MSK signals at bit rate of 20 and 80 Gbits/s were successfully generated using the proposed MSK transmitter.
View Article and Find Full Text PDFWe propose an optical initial phase control technique for external modulation in the format of minimum-shift keying (MSK). In this scheme, the optical phase discontinuities inherent to external frequencyshift- keying (FSK) modulation are compensated by use of an initial phase controller in conjunction with a FSK modulator. We present the principle of the control method and then numerically and experimentally prove that the signal has a modulation spectrum more compact than that of conventional binary phase-shift keying.
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