Electro-optical tuning flat filter

Abstract

A filter which applies cascade analog birefringent module can achieve characteristcs of pass band and stop band with large flat width, high isolation degree and very small interval of spectral frequency by controlling rotation angle of polarization rotating disc and optical path of light in each analog birefringent module, of which two medias in each analog module are applied with materials of optical glass and electrooptical crystal separately. The adjustable filter which has low voltage-high tuning speed can be obtained by optimum-cutting the crystal and selecting structure of voltage being loaded.

Description

Technical field: [0001] The invention relates to a tunable filter element with flattened passband and stopband characteristics applied in an optical system, which is mainly used for wavelength selection of wavelength division multiplexed signals in a dense wavelength division multiplexing (DWDM) system, and furthermore Can be used for any tuning filter that needs to flatten the spectral transmittance function. Background technique: [0002] A device that only allows light of a specific wavelength (frequency) to pass smoothly is called an optical filter, and if the wavelength (frequency) passed can be changed, it is called a wavelength tunable filter. This device has extensive application value in wavelength division multiplexing (WDM) systems, all-optical switching systems and other fields. Due to its advantages in technology and cost, DWDM plays an important role in the expansion of optical fiber communication systems and networks. In order to separate a series of single ...

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Problems solved by technology

Since the γ with the largest electro-optic coefficient value 33 Also only 32.2×10 -12 m / v, so the voltage applied during modulation is larger

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