Device for increasing extinction ratio

Abstract

The invention provides a device for increasing extinction ratio. The device comprises a DML, an isolator and an optical fiber, and further comprises a first filter plate, a lens, a second filter plate and a photodiode component, wherein the isolator is arranged between the DML and the first filter plate; the lens is arranged between the optical fiber and the second filter plate; the first filter plate is used for enhancing the extinction ratio of optical signals output by the DML; the lens is used for ensuring that an included angle is formed between the optical signals and the central optical axis of the lens, so as to enable the second filter plate to reflect the optical signals to the optical fiber to realize transmission; the second filter plate is used for performing upper and downlink light splitting on the optical signals; the photodiode component comprises a first photodiode and a second photodiode; the first photodiode is used for detecting the state of the optical signals in the downlink and feeding back the state to the DML; the second photodiode is used for performing photovoltaic conversion on the optical signals in the uplink, so that by adoption of the device, the extinction ratio is increased, and meanwhile the insertion loss and the polarization dependence in an optical path are reduced.

Description

technical field [0001] Embodiments of the present invention relate to optical fiber communication technology, and in particular to a device for increasing extinction ratio. Background technique [0002] In an optical communication network, data is sent and received by an optical transmitter and an optical receiver. The extinction ratio can directly affect the sensitivity of the optical receiver. In order to increase the extinction ratio, a Directly Modulated Laser (DML) is usually used to increase the amplitude of the modulation signal to increase the extinction ratio, but the use of DML will cause a large chirp , resulting in larger dispersion and poorer signal quality. [0003] In the prior art, the solution to the chirp problem is to use DML in combination with a multi-cavity filter, such as figure 1 As shown, an isolator, a 45° filter and a multi-cavity filter are arranged in sequence in front of the optical path. The 45° filter can realize uplink and downlink light sp...

AI Technical Summary

Problems solved by technology

[0004] However, in the solutions of the prior art, the polarization dependence of the 45° optical filter causes the transmission coefficients of the high-spe...

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