Micro-optical assembly of 25G BiDi optical module for 5G forward transmission

Abstract

The invention provides a micro-optical assembly of a 25G BiDi optical module for 5G forward transmission. The assembly is characterized in that the assembly comprises a bottom plate, a pentagonal-prism-shaped glass substrate is placed on the bottom plate. A Tx optical filter for allowing emitted light to enter is attached to the left side surface of the glass substrate. The right side face of theglass substrate is plated with an antireflection film used for allowing received light to enter and allowing emitted light to be emitted out, a reflecting mirror is attached to the lower right inclined face of the glass substrate, and an Rx optical filter used for allowing the received light entering the Tx optical filter from the antireflection film to be reflected to the reflecting mirror to bereflected again to be output to a receiving end is attached to the upper side face of the glass substrate. Compared with the prior art, according to the micro-optical assembly, an Rx optical filter and a Tx optical filter are arranged on a glass substrate. The incident angles of the Rx optical filter and the Tx optical filter are small, the allowable incident angle error is large, the overall structure is compact, the size is small, the effective clear aperture reaches 0.6 mm, the assembly difficulty is reduced, the assembly cost of a 25G BiDi optical module for 5G forward transmission is reduced, and the packaging requirement of an SFP28 optical module is easily met.

Description

technical field [0001] The invention relates to the field of optical communication, in particular to a micro-optical component of a 25G BiDi optical module used for 5G forward transmission. Background technique [0002] BiDi optical module is a single-fiber bidirectional optical module, which uses WDM technology to transmit and receive two central wavelengths in different directions to realize bidirectional transmission of optical signals on one optical fiber. The optical module generally has two ports: the transmitting port (Tx) and the receiving port (Rx), while the BiDi optical module has only one port, which is filtered by the filter in the optical module, and simultaneously completes the transmission of an optical signal of one wavelength and the other. Reception of optical signals of one wavelength (the wavelengths of BiDi optical modules are combined), so BiDi optical modules must be used in pairs, and its biggest advantage is to save fiber resources. [0003] The ex...

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Problems solved by technology

[0004] However, the above two schemes have the following defects: 1) For the first scheme, the single-chip 45° filter needs to reflect the Rx light and transmit the Tx light with a small center wavelength interval, and the incident angle is required to be 45°. The WDM film is difficult to realize in the film system design and coating process, the product yield is low, and the cost is high. At the same time, the 45° filter is sensitive to the central wavelength and the incident angle error, and the required assembly angle error is required to be less than 0.1°. It is required to adjust the Rx end, Tx end and 45° filter online when 25G BiDi optical module is assembled, which leads to complex assembly process of 25G BiDi optical module, low production efficiency and high production cost; 2) For the second solution, (1 ) The three sides of the metal substrate with Rx filter, Tx filter and reflector have high requirements for angle accuracy, and there are grooves on the metal substrate for light transmission, resulting in high processing requirements and high costs for the metal substrate; (2) The light apertures of the Rx filter, Tx filter and reflector are in the groove opening of the metal substrate, and some are attached to the side of the metal substrate, which causes the Rx filter, Tx filter and reflection The size of the mirror is 0.6mm larger than the aperture to meet the reliability requirements, resulting in a small ratio of the aperture to the size of the Rx filter, Tx filter and reflector, wasting the Rx filter, Tx filter sheets and mirrors, which ultimately lead to high production costs

(3) At the same time, there is still space for pasting the Rx filter, Tx filter and reflector in addition to the groove on the metal substrate, and the size of the Rx filter, Tx filter and reflector is also larger than The required optical aperture is much larger, which leads to a larger component size, which is difficult to meet the requirements of SFP28 optical module packaging, or needs to compress the space of other components to meet the requirements of SFP28 optical module packaging

(4) The Rx filter of this structure has an incident angle of 0°, and the WDM film and AR film will have a large amount of reflected light returning to the COM end according to the original optical path, resulting in a small return loss of the optical module, which affects its paired The performance and power stability of the laser at the TX end of the optical module

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