Abstract:
PURPOSE: A noise cancellation device in an optical communication system is provided to cancel noise in a low frequency range by using an optical detection unit having differential output. CONSTITUTION: An optical detection unit (10) outputs differential output by converting optical signal received from an optical network unit (ONU) into an electrical signal. The differential output includes first output and second output. A low pass filter (LPF) (20) passes a signal in a specific low frequency range in the second output. A variable phase trimmer (VPT) (35) controls a phase of the first output to make a signal passed through the LPF and the first output inputted from the optical detection unit destructively interfere with each other. A coupling unit (30) couples the first output and the output of the LPF. [Reference numerals] (30) Coupling unit; (AA) Optical path; (BB) Electrical path
Abstract:
PURPOSE: A transmission apparatus and method for a broadcast signal of a broadband light source using polarization multiplexing, and an optical access network including the same are provided to transmit the broadcast signal using different polarization beams. CONSTITUTION: A polarization beam splitter(201) splits an optical signal outputted from an unpolarized broadband light source into a first polarization beam and a second polarization beam. An external modulator(203) outputs modulated light for modulating a broadcast signal using the first polarization beam. A polarization beam combiner(206) combines the modulated light with the second polarization beam outputted from the polarization beam splitter. A first polarization beam controller(202) is provided between the polarization beam splitter and the external modulator. A second polarization beam controller(204) is provided between the external modulator and the polarization beam controller. A third polarization beam controller(205) is provided between the polarizing beam splitter and the polarization beam controller. [Reference numerals] (AA) First polarized light; (BB) Second polarized light
Abstract:
WDM-PON 시스템에서 잡음제거 장치가 개시된다. 제1파이버(FF)로 연결된 중앙 기지국(CO)과 원격노드(RN)와, 제2파이버(DF)로 연결되는 상기 RN과 광네트워크유닛(ONU)을 포함하는 파장분할 다중방식 수동형 광통신망(WDM-PON) 시스템에서, 상기 ONU로부터 상기 CO를 향하는 상향신호에 혼입되는 후방반사에 의한 잡음을 제거하는 장치는, 상기 ONU로부터 수신되는 광신호를 수신하여 전기신호로 변환하는 광검출부와, 상기 광검출부에 의해 변환된 전기신호에서, 후방반사에 의한 잡음을 제거하는 고역통과필터(PHF)를 포함한다.
Abstract:
PURPOSE: A noise eliminating apparatus in a wavelength division multiplexed-passive optical network (WDM-PON) system is provided to add a high pass filter (PHF) and to remove a noise. CONSTITUTION: An optical detecting unit (131) receives an optical signal received from an optical network unit (ONU). The optical detecting unit converts the received optical signal into an electric signal. A PHF removes a noise by back reflection in the electric signal converted by the optical detecting unit. An arrayed waveguide grating (AWG) (200) performs the wavelength division distribution of the signal received through a first fiber. The AWG applies the distributed signal to the optical detecting unit. [Reference numerals] (110) Light source; (130) Receiving unit; (AA,BB) Reflection; (CC) Transmission unit; (DD) Reflection I; (EE) Reflection II