Device and method for locking optical signal frequency by demodulator in DPSK system
A technology of optical signal frequency and demodulator, applied in the field of optical communication, can solve problems such as system performance degradation, achieve the effect of optimizing receiving performance and avoiding changes in input optical power
Active Publication Date: 2009-11-25
ZTE CORP
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Problems solved by technology
[0010] The technical problem to be solved by the present invention is to provide a device for locking the frequency of an optical signal by using a demodulator in a DPSK system, and provide a method for locking the frequency of an optical signal by using a demodulator on the basis of the device. Solved the problem of system performance degradation caused by optical signal frequency drift in DPSK system
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[0034] The present invention will be described in further detail below in conjunction with the accompanying drawings.
[0035] Such as Figure 5 As shown, the device for using a demodulator to lock the optical signal frequency in the DPSK system of the present invention includes the following modules: DPSK sending unit 1, transmission link 2, DPSK receiving unit 3, wherein DPSK receiving unit 3 also includes a demodulator 31 . Balance receiver 32 , first current monitoring unit 33 and second current monitoring unit 34 , microprocessing unit 35 , demodulator adjustment circuit 36 and signal recovery unit 37 . Two photodetectors PD1 and PD2 are included in the balanced receiver 32, and the filter wavelength adjustment parameter of the demodulator 31 is adjusted, and the currents of PD1 and PD2 will change accordingly, and conform to certain rules. When the current reaches the maximum value, the other current reaches the minimum value. The filter wavelength of the demodulator...
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The invention relates to a device for locking an optical signal frequency by a demodulator in a DPSK system, which comprises a DPSK sending unit, a transmission link and a DPSK receiving unit, wherein the DPSK receiving unit comprises a demodulator, a balanced receiver, a microprocessing unit, a demodulator adjusting circuit, a signal restoring unit, a first current monitoring unit and a second current monitoring unit; the invention also provides a method for the locking the optical signal frequency by the demodulator in the DPSK system, which comprises the following steps: generating a bit sequence of specific patterns through the DPSK sending unit, sending the bit sequence to the DPSK receiving unit, acquiring a current monitoring value from the DPSK receiving unit, normalizing the current monitoring value through the microprocessing unit, finding the maximum current value, and finally locking the optical signal frequency. The invention avoids a faulty adjustment effect of the demodulator caused by input optical power change and detection current pattern change, realizes the optical signal frequency locking by the demodulator, and optimizes the receiving performance of the DPSK system.
Description
technical field [0001] The invention relates to the field of optical communication, in particular to a device and method for locking the frequency of an optical signal by using a demodulator in a differential phase shift keying (Differential Phase Shift Keying, DPSK) system in a wavelength division multiplexing device. Background technique [0002] The new modulation pattern based on the principle of phase modulation is superior to the traditional pattern based on intensity modulation, and has been widely researched and applied in high-speed and long-distance optical transmission. Phase modulation technology achieves signal reception through two methods: coherent demodulation and direct detection (also known as self-coherent demodulation). Among them, the implementation of coherent demodulation is more complicated, and the direct detection method is relatively simple. The direct detection method first uses a delay-interferometer (Delay-Interferometer, DI) as a demodulator (...
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IPC IPC(8): H04B10/158H04L27/22H04B10/66
Inventor 沈百林周伟勤
Owner ZTE CORP