CN107505702B

CN107505702B - Micro-electromechanical variable optical attenuator

Info

Publication number: CN107505702B
Application number: CN201710795665.XA
Authority: CN
Inventors: 梁联长
Original assignee: Sichuan Zi Guan Photonics Technology Co Ltd
Current assignee: Sichuan Zi Guan Photonics Technology Co Ltd
Priority date: 2017-09-06
Filing date: 2017-09-06
Publication date: 2020-01-03
Anticipated expiration: 2037-09-06
Also published as: CN107505702A

Abstract

The invention relates to the field of optical devices, discloses a micro-electromechanical variable optical attenuator and solves the problem of poor reliability of the existing MEMS VOA. The optical fiber collimator comprises a TO tube seat, an MEMS chip, a tube cap and an optical fiber collimator, wherein the MEMS chip is arranged on the TO tube seat, the TO tube seat is connected with the tube cap, a closed space is formed between the TO tube seat and the tube cap, the MEMS chip is positioned in the closed space, the front end of the tube cap is provided with a window, a support table is arranged around the window, a transparent window sheet for light incidence is arranged on the support table, and the optical fiber collimator is arranged right in front of the transparent window sheet. The invention is suitable for optical fiber transmission control.

Description

Micro-electromechanical variable optical attenuator

Technical Field

The present invention relates to the field of optical devices; in particular to a micro-electromechanical variable optical attenuator (MEMS VOA).

Background

The variable optical attenuator, VOA, is an important optical transmission device in the intelligent optical network, is a key component for forming an optical amplifier, plays a role in power balance in an optical fiber communication system, and is widely applied to channel gain balance and optical receiving device protection of a wavelength division multiplexing system WDM/DWDM. The reconfigurable optical add-drop multiplexer ROADM, the pre-equalization combiner VMUX, the gain flattening EDFA and other modules can be formed by the reconfigurable optical add-drop multiplexer ROADM, the pre-equalization combiner VMUX, the erbium-doped optical fiber amplifier EDFA and other optical devices.

The variable optical attenuator is distinguished according to the manufacturing process, and comprises a traditional mechanical type, a waveguide type, a liquid crystal type, a micro-electromechanical MEMS type and the like. Among them, the waveguide type and liquid crystal type optical energy equalizer technologies are not yet mature, and few commercial products are available. The mechanical type is the most mature, but the mechanical type is large in size, complex in structure and inconvenient to operate. For example, patent No. CN02136828.7, "electromagnetic driving dislocation type micromechanical variable optical attenuator", proposes ー methods for implementing an optical attenuator by controlling the optical fiber dislocation displacement using an electromagnetic driving force and an elastic body. The device structure needs mechanical components such as the movable platform, the positioning groove and the elastic body, so that the structure is complex, mechanical fatigue is easily generated in the elastic body, the performance of the device is affected, and the service life of devices is shortened.

There are two main methods for implementing MEMS VOAs: finger structures based on the diffraction principle and rotating mirror structures based on the reflection principle, in particular the latter, are more common. MEMS VOA based on rotating mirror structure, its theory of realization is: light is emitted from one optical fiber in the double-fiber tail fiber, is collimated by the lens and enters the reflector, the reflected light is converged by the lens and is coupled into the other optical fiber in the double-fiber tail fiber, and the angle of the reflector is continuously changed by adjusting the driving voltage of the MEMS chip, so that the light intensity coupled into and out of the optical fibers is changed, and the attenuation is tunable.

Chinese patent CN201610507439.2 discloses a rotating mirror type MEMS variable optical attenuator, as shown in fig. 1, including: the device comprises an input optical fiber A, an output optical fiber B, a double-core capillary 72, a collimating lens 71, a long glass tube 73, a short glass tube 5, a TO tube cap 3, a glass window 4, an MEMS chip 2 and a TO tube seat 1; the MEMS chip 2 is fixedly arranged on the TO tube seat 1 and is electrically connected with a power-on pin P on the TO tube seat; the TO tube cap 3 and the TO tube seat 1 are hermetically packaged TO form an airtight cavity, and the MEMS chip 1 is located in the airtight cavity; the TO pipe cap 3 is provided with a glass window 4, the front side and the back side of the glass window 4 are coated with antireflection films, the glass window 4 is sintered on the TO pipe cap 3 through glass cement so as TO have good air tightness, and the leakage rate of an airtight cavity formed between the TO pipe cap 3 and the TO pipe seat 1 is less than or equal TO 5E-9 Pa.m 3/s. As can be seen from FIG. 1, since the glass window 4 is sintered on the inner side of the tube cap 3, the glass window 4 of the variable optical attenuator is easily affected by the negative pressure inside the tube cap 6 during the plugging and unplugging processes, so that the glass window 6 falls off, and the tube cap 3 loses the sealing performance; in addition, the vibration of the variable optical attenuator during the plugging process is also likely to cause cracks between the tube seat and the tube cap, and between the tube cap and the short glass.

Moreover, the current TO tube seat 1 generally adopts a 3-pin design, wherein a PA pin is connected with the anode of the MEMS chip, a PB pin is connected with the metal table, and a PC pin is connected with the cathode of the MEMS chip, since there are more cathodes of the MEMS chip 2, generally 3, if a plurality of cathodes are simultaneously connected on the same position on the PB pin, the problem of welding such as cold solder occurs easily, and the cathode of the MEMS chip 2 is at most one closest TO the PB pin, and the rest cathodes are relatively far away from the PB pin, and the far distance means that too many gold wires are used, which increases the production cost.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the MEMS VOA is provided, and the problem that the existing MEMS VOA is poor in reliability is solved.

In order to solve the problems, the invention adopts the technical scheme that: an MEMS VOA comprises a TO tube seat, an MEMS chip, a tube cap and an optical fiber collimator, wherein the MEMS chip is arranged on the TO tube seat, the TO tube seat is connected with the tube cap, a closed space is formed between the TO tube seat and the tube cap, the MEMS chip is positioned in the closed space, the front end of the tube cap is provided with a window, a transparent window sheet for light incidence is arranged on the window, and the optical fiber collimator is arranged right in front of the transparent window sheet; the window is characterized in that a support table is arranged around the window, and the transparent window sheet is arranged on the support table.

Further, the transparent window sheet is a glass window sheet.

Furthermore, the glass window sheet is adhered to the supporting platform through optical cement

Further, the TO tube seat includes contact pin and metal platform, and the contact pin includes first contact pin and second contact pin, and wherein, first contact pin switches on with the metal platform electrical property, and the second contact pin switches on through gold thread and MEMS chip's positive pole electrical property, and MEMS chip's negative pole switches on through gold thread and metal platform electrical property.

Furthermore, the gold wire has an arc lifting, the height difference between the highest position of the arc lifting and the anode or the cathode of the MEMS chip is marked as h, and h is more than or equal to 0.5mm and less than or equal to 1 mm.

Furthermore, the invention also comprises a glass tube and a metal adapter ring, wherein the glass tube is connected with the tube cap, the outer diameter of the glass tube is equal to that of the tube cap, and the metal adapter ring simultaneously encapsulates the glass tube and the tube cap on the inner side of the glass tube and the tube cap.

Further, the metal adapter ring covers the whole pipe cap on the inner side of the metal adapter ring, and at least two thirds of the glass pipe is packaged on the inner side of the metal adapter ring.

Furthermore, the invention also comprises a metal outer sealing pipe and a metal outer sealing cap; the TO tube seat, the MEMS chip, the tube cap, the optical fiber collimator, the glass tube and the metal adapter ring are all located on the inner side of the metal outer sealing tube, and the metal outer sealing tube is matched with the metal outer sealing cap.

The invention has the beneficial effects that: according to the invention, the supporting tables are arranged on the periphery of the window, and the transparent window sheet is arranged on the supporting tables, so that the transparent window sheet is not influenced by negative pressure in the plugging and unplugging process, and the reliability is improved; meanwhile, the tube seat can adopt the design of 2 contact pins, and because the cathode of the MEMS chip is conducted with the metal platform through the gold thread, the cathode of the MEMS chip can be connected everywhere through the gold thread dispersion points nearby, thereby reducing the risk of insufficient soldering, reducing the use of the gold thread and the contact pins, and saving the cost.

In addition, this through the outside suit metal switching ring at glass pipe and pipe cap, can avoid owing to pull out the process vibration of inserting and cause the tube socket and the pipe cap crack to and the crack between glass pipe and the pipe cap, further improved MEMS VOA reliability.

Drawings

Fig. 1 is an assembled view of a prior art MEMS VOA;

FIG. 2 is an exploded view of the present invention;

FIG. 3 is an assembled view of the present invention;

FIG. 4 is an assembled vertical sectional view of the present invention.

Numbering in the figures: the optical fiber collimator comprises a TO tube seat 1, an MEMS chip 2, a tube cap 3, a window 31, a glass window sheet 4, a glass tube 5, a metal adapter ring 6, an optical fiber collimator 7, a lens 71, a capillary 72, an outer sealing tube 73, an outer sealing tube 8, an outer sealing cap 9, an optical fiber protective rubber sleeve 10, an incident optical fiber A and an output optical fiber B.

Detailed Description

An embodiment provides a MEMS VOA, as shown in fig. 2, 3, and 4, including a TO stem 1, a MEMS chip 2, a cap 3, a fiber collimator 7, an input fiber a, an output fiber B, a glass tube 5, a metal adapter ring 6, a metal outer sealing tube 8, and a metal outer sealing cap 9. The MEMS chip 2 is arranged on the TO tube seat 1, the TO tube seat 1 is connected with the tube cap 3, a closed space is formed between the TO tube seat 1 and the tube cap 3, the MEMS chip 2 is positioned in the closed space, the front end of the tube cap 3 is provided with a window 31, a support table is arranged around the window 31, a glass window sheet 4 used for light incidence is arranged on the support table, and the optical fiber collimator 7 is arranged right in front of the glass window sheet 4; the glass tube 5 is connected with the tube cap 3, the outer diameter of the glass tube 5 is equal to that of the tube cap 3, the whole tube cap 3 is sleeved on the inner side of the metal adapter ring 6, and at least two thirds of the glass tube 5 is sleeved on the inner side of the metal adapter ring 6; the TO tube seat 1, the MEMS chip 2, the tube cap 3, the optical fiber collimator 7, the glass tube 5 and the metal adapter ring 6 are all located on the inner side of the metal outer sealing tube 8, and the metal outer sealing tube 8 is matched with the metal outer sealing cap 9.

As shown in fig. 3, the TO stem 1 includes 2 pins and metal pads 11, one pin PA is directly electrically connected TO the metal pad, the other pin PB is electrically connected TO the anode of the MEMS chip 2 through a gold wire, and the cathode of the MEMS chip 2 is electrically connected TO the metal pad through a gold wire. And the gold thread has the arc of carrying, and the arc of carrying is carried in the design can prevent that the gold thread from being close to or pasting in MEMS chip's surface, avoids burning out MEMS chip. The height difference between the highest position of the arc lifting and the anode or the cathode of the MEMS chip is recorded as h, and experience summary shows that the arc lifting effect is best when h is more than or equal to 0.5mm and less than or equal to 1 mm.

The working principle of the embodiment is as follows:

light enters a capillary 72 of the optical fiber collimator 7 from the input optical fiber A and reaches a lens 71 of the optical fiber collimator 7, the light after passing through the optical fiber collimator 7 enters the tube cap 3 from the window 31 and reaches the MEMS chip 2, the light is coupled between the MEMS chip 2 and the lens 71, and the angle of the reflector is continuously changed by adjusting the driving voltage of the MEMS chip 2, so that the light intensity coupled into and out of the optical fiber is changed, and the attenuation is tunable; the light reflected by the MEMS chip 2 is output by the optical fiber collimator 7 and finally enters the output optical fiber B.

The foregoing describes the general principles and features of the present invention and, together with the general principles of the invention, further modifications and improvements thereto, may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

Claims

1. A micro-electromechanical variable optical attenuator comprises a TO tube seat, an MEMS chip, a tube cap and an optical fiber collimator, wherein the MEMS chip is arranged on the TO tube seat, the TO tube seat is connected with the tube cap, a closed space is formed between the TO tube seat and the tube cap, the MEMS chip is positioned in the closed space, the front end of the tube cap is provided with a window, a transparent window sheet for light incidence is arranged on the window, and the optical fiber collimator is arranged right in front of the transparent window sheet; the window is characterized in that a supporting table with a step part is arranged around the window, the transparent window sheet is arranged on the supporting table, and one side of the transparent window sheet close to the sealed space is abutted against the step.

2. The variable optical attenuator of the microelectromechanical type of claim 1 wherein the transparent pane is a glass pane.

3. The variable optical attenuator of the microelectromechanical type of claim 2 wherein the glazing is bonded to the support stage by optical glue.

4. The variable optical attenuator of claim 1, wherein the TO header comprises a pin and a metal pad, the pin comprises a first pin and a second pin, wherein the first pin is electrically connected TO the metal pad, the second pin is electrically connected TO the anode of the MEMS chip via a gold wire, and the cathode of the MEMS chip is electrically connected TO the metal pad via a gold wire.

5. The micro-electromechanical variable optical attenuator according to claim 4, wherein the gold wire has a lifting arc, and the height difference between the highest position of the lifting arc and the anode or cathode of the MEMS chip is h, which is 0.5mm ≤ h ≤ 1 mm.

6. The variable optical attenuator of the micro-electromechanical type as claimed in claim 1 or 4, further comprising a glass tube connected to the cap and having an outer diameter equal to that of the cap, and a metal adapter ring encapsulating the glass tube and the cap at the same time.

7. The variable optical attenuator of the microelectromechanical type of claim 6 wherein the metal adapter ring encapsulates the entire tube cap on its inside and encapsulates at least two-thirds of the glass tube on its inside.

8. The variable optical attenuator of the microelectromechanical type of claim 7 further comprising a metal outer sealing tube and a metal outer sealing cap; the TO tube seat, the MEMS chip, the tube cap, the optical fiber collimator, the glass tube and the metal adapter ring are all located on the inner side of the metal outer sealing tube, and the metal outer sealing tube is matched with the metal outer sealing cap.