Shanghai Finisar has recently proposed the optical device connection technology

Finisar is one of the world's most famous suppliers of optical communication devices. Due to China's good economic development and talent advantages, Finisar has listed its subsidiary in Shanghai as a key point of its global development strategy. Moreover, with the development of communication technology, 5G has also created different sparks with optical devices.

At present, single fiber bidirectional transmission (single fiber bidirectional) has become one of the main technologies in the optical transmission solution of 5G optical fiber communication field. The premise of achieving single fiber bidirectional is that the transmitting end and the receiving end of the optical transceiver module use the same collimator to couple into or out of the optical fiber; therefore, the connection and coupling process of the collimator has become the key process in the preparation of single fiber bidirectional transceiver optical modules for optical communication.

The existing optical module box and collimator connection process mainly uses laser welding or glue bonding. The laser welding process has disadvantages such as large alignment error, multi-step process, and low mass production efficiency; while the glue bonding method has extremely high requirements on alignment accuracy, glue adhesion and curing, as well as reliability such as baking and thermal cycling; at the same time, the above two methods both require active devices to align and correct the connection process, and the process and equipment operation are complicated.

To this end, Shanghai Finisar applied for an invention patent entitled "Optical device structure, connection device and method" (application number: 202010016655.3) in January this year, and the applicant was Finisar Optoelectronics Communications (Shanghai) Co., Ltd.

Figure 1 Schematic diagram of the structure of the optical device connection device

Figure 1 is a schematic diagram of the structure of the optical device connection device proposed in the patent, which mainly includes a collimator alignment system, a coupling angle monitoring system and a pressure real-time monitoring system. The collimator alignment system realizes the initial alignment of the collimator and the hole of the optical module box, maintains the angle of the collimator during the pressing process and after the final coupling; the coupling angle monitoring system monitors the angle of the collimator during the interference fit pressing process; the pressure real-time monitoring system detects the relationship between the pressure and the interference distance during the pressing process and the pressure the collimator is subjected to during the pressing process.

One of the more important parts is the collimator alignment system, which includes an optical module box fixing fixture 8, a collimator XY movable adjustment platform 3, a collimator fixing fixture 4 and a position identification system 5. The optical module box fixing fixture 8 and the collimator fixing fixture 4 are used to make the axis of the hole of the optical module box 7 parallel to the axis of the collimator 6, and then the position of the hole is identified by the position identification system 5, and the collimator 6 is made coaxial with the hole using the collimator XY movable adjustment platform 3.

Figure 2 Flowchart of the method for connecting optical device structures

FIG2 specifically relates to a method for connecting an optical device structure, which mainly includes the following five steps. First, a collimator and an optical module box are provided, wherein the insertion end and the hole are designed with interference fit (step S11). Then, the collimator and the optical module box are installed and aligned, the collimator and the optical module box are fixed on a fixture, the position of the hole of the optical module box is identified by a position recognition system, the collimator is adjusted to be concentric with the hole in the XY direction, and the collimator is pressed into the hole until the interference fit position is reached (step S12). Then, the pressing parameters are set, and the press presses the collimator into the hole of the optical module box (step S13). Finally, the pressing process parameter curve is extracted and compared with the theoretical parameter curve to determine whether the connection is qualified (steps S14, 15).

The above is the introduction of this patent of Shanghai Finisar. The optical device connection structure proposed in the patent can realize the precise alignment of the collimator and the optical module box in a passive state, and use interference fit to couple the collimator. It does not require active coupling connection solutions such as laser welding and gluing to achieve passive coupling connection of the collimator. At the same time, it has a real-time monitoring and judgment system, with a simple overall structure and process, convenient installation, low cost and high production efficiency.