Switch three QPSK modulators twice often and save 50% of power over radio, wire and fiber channels. Switch 15 QPSK modulators 4 often and gain your profit in DWDM systems over ULH market.

Switch three QPSK modulators twice often and save 50% of power over radio, wire and fiber channels. Switch 15 QPSK modulators 4 often and gain your profit in DWDM systems over ULH market.

A. O. Nekuchaev and S. A. Shuteev          

Moscow State University, Moscow, 119991 Russia

e_mail: Orovich@clines.ru

        The idea to use spectral redundancy was patented the Department of Physics, Moscow State University [1]. . The time is divided into cycles, each of which is equal to 2 microcycles. Two wavelengths P11,P12,P13,P14,P21,P22,P23,P24– are called pilots (the duration of each wavelength is equal to one circle) each of which corresponds to a three-bit chip: 000, 001, and so on to 111. First bit is determined by wavelength and second and third by QPSK modulation. Waves S1–S4 are called slaves. Slave Si means that, in a given microcycle, the current symbol is the same as current wavelength   with phase i of current  microcycle. Every microcycle carries new wavelength with 4 possible phases.

 Transmission of the sequence P11–P14,  P21–P24correspond to P11,S2,P13,S4,P21,S2,P23,S4.

Transmission of the sequence P11,P11,P11,P11, P21,P21,P21,P21correspond to P11,S1,P11,S1,P21,S1,P23,S1.

Obviously bit rate the same as for three independent QPSK modulators, but power 1.5 times less.

   Now let us consider P1i,..,P2i,…,P3i,….P8i (i=1,2,3,4)   together 8 different wavelengths and S11(i), S12(i),S21(i),S22(i),S31(i),S32(i),S33(i) together 7 different wavelengths,  S1 and S2 are degenerated twice, S3 are degenerated thirdly. Slave Si means that, in a given microcycle, the current symbol is the same as  wavelength S microcycles ago  with phase i of current  microcycle. Altogether there are 8+7=15 different wavelengths. Every pilot carries 3 bits as colour and 2 bits as QPSK, together 5 bits. The cycle is equal 4 microcycles. In any time there are 4 different wavelengths. Every wavelength starts in microcycle and has duration 1 cycle.

During cycle 4*5=20bits with 15 different wavelengths are transmitted in proposed method against 30 bits with 15 different wavelengths as usually. So total capacity will be 6 times with 15 or 90 different wavelengths, which corresponds to 9*(20/30)=6Terabit/sec opposite to 9.0 in usual method, but power will be  15/4=3.75 times less .10lg3.75=5.74dB. Over ULH market and EULH 4 out 15 will be better than 2 out 3, which in turn will be better than existed method.

Usual method

λ 1 λ 2………………………………………………………………………… λ90

Total capacity 9.0Terabit/sec , total power P

New method

λ 1 λ 2………………………………………………………………………… λ90

Total capacity 6.0 Terabit/sec , total power   4P/15

Transmission of the sequence

                          P11 P12   P13   P14   P21 P22   P23    P24

corresponds  to P11 S112 S213 S314 P21  S112 S213 S314

DRS is 15/4 less than in usually

Security of data is 88!=10^134

        REFERENCES

1. A. O. Nekuchaev and U. A. S. Yusupaliev, RF Inventor’s Certificate No. 2161374 (MGU, Fizicheskii Fakul’tet, 2004).