An optical device without isolator

Abstract

The application relates to an optical device without an isolator, comprising a transmitting end, a polarizer, a first filter, a receiving end and a pigtail, the transmitting end is arranged obliquely relative to the polarizer, the first filter is arranged obliquely between the polarizer and the pigtail, and the receiving end is arranged on the reflection light path of the first filter; linearly polarized light emitted by the transmitting end is coupled to the pigtail after being transmitted by the polarizer and the first filter in sequence; and a received optical signal recycled from the pigtail enters the receiving end after being reflected by the first filter. The application effectively suppresses the interference of reflected light. The traditional scheme needs an optical isolator, and the application omits the optical isolator through specific optical path structure design, reduces the device manufacturing cost, and meets the application requirements of consumer-grade optical communication products.

Description

Technical Field

[0001] This application relates to the field of BOSA component technology, and more particularly to an optical device without an isolator. Background Technology

[0002] BOSA (Optical Transmitter-Receiver Assembly) is a core device in the field of optical communication and is widely used in optical modules, fiber optic modems and other equipment. Its core function is to integrate "optical signal transmission" and "optical signal reception" into one unit. It achieves miniaturization by sharing some optical paths (such as pigtails and filtering elements). It typically includes key components such as a transmitter (such as an LD laser), a receiver (such as a PD detector), optical filtering elements, and pigtails.

[0003] In the actual operation of BOSA, there is a key technical problem: the optical signal emitted from the transmitter will generate reflected light in the transmission path (such as through the interface of pigtail and filter) (e.g., echo from the end face of the pigtail, residual reflection from the filter). If these reflected lights are coupled back to the transmitter, it will cause problems such as mode switching, power fluctuation and shortened lifespan at the transmitter, which will seriously affect the transmission stability of the optical signal.

[0004] To address the aforementioned reflected light interference problem, the commonly used approach in existing technologies is to connect an optical isolator (a non-reciprocal element based on the Faraday effect) in series in the transmission optical path of the BOSA (Optical Optical Array Receiver Array). This isolator's unidirectional transmission characteristic blocks reflected light from entering the transmitter in the opposite direction. However, optical isolators have significant drawbacks: their core materials (such as yttrium iron garnet (YIG) crystals) and precision manufacturing processes result in high costs, typically accounting for 15%-30% of the total cost of a BOSA. This significantly increases the overall manufacturing cost of optical devices, hindering cost control for consumer-grade optical communication products.

[0005] Therefore, there is an urgent need for a new type of optical device structure that can effectively suppress reflected light interference while eliminating the need for an optical isolator, thereby reducing device manufacturing costs and meeting the application requirements of consumer-grade optical communication products. Utility Model Content

[0006] The purpose of this application is to provide an optical device without an isolator to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, this application provides the following technical solution:

[0008] An optical device without an isolator includes a transmitter, a polarizer, a first filter, a receiver, and a pigtail. The transmitter is tilted relative to the polarizer, the first filter is tilted between the polarizer and the pigtail, and the receiver is disposed on the reflected light path of the first filter.

[0009] The linearly polarized light emitted from the transmitter is coupled to the pigtail after being transmitted through the polarizer and the first filter in sequence.

[0010] The received optical signal recovered from the pigtail fiber is reflected by the first filter and then enters the receiving end.

[0011] Furthermore, the light-emitting surface of the first filter is tilted toward the pigtail relative to the polarizer.

[0012] Furthermore, the tilt angle of the first filter is 45°.

[0013] Furthermore, the end of the pigtail near the first filter is coated with an anti-reflective film.

[0014] Furthermore, it also includes a second filter, which is a 0° incident filter used to filter stray light in the received light. The second filter is disposed on the reflected light path of the first filter and is located between the first filter and the receiving end.

[0015] Furthermore, it also includes a housing, with the transmitter, receiver and pigtail respectively passing through three different surfaces of the housing, and the polarizer, first filter and second filter fixedly disposed inside the housing.

[0016] Furthermore, the emitting end is a laser diode.

[0017] Furthermore, the receiving end is a photodiode.

[0018] The technical solutions provided in this application have the following advantages compared with the prior art:

[0019] The optical device without an isolator provided in this application embodiment has an emitter tilted relative to a polarizer. Linearly polarized light emitted from the emitter is directed at a specific angle to the polarizer and transmitted through it due to the tilted arrangement. A first filter is tilted between the polarizer and the pigtail. The linearly polarized light transmitted through the polarizer is then coupled to the pigtail after being transmitted through the first filter. The received optical signal recovered from the pigtail is reflected by the first filter, changing its optical path direction before entering the receiver. Through this specific optical path design, utilizing the tilted arrangement and the reflection and transmission characteristics of light, the separate transmission of emitted and received light is achieved.

[0020] This application effectively suppresses reflected light interference. Traditional solutions require optical isolators, while this application, through a specific optical path structure design, eliminates the need for optical isolators, reduces device manufacturing costs, and meets the application requirements of consumer-grade optical communication products. Attached Figure Description

[0021] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0024] Figure 1 This is a cross-sectional schematic diagram of an optical device without an isolator, provided as an embodiment of this application.

[0025] Figure 2 This is a perspective view of an optical device without an isolator, provided as an embodiment of this application.

[0026] Explanation of reference numerals in the attached figures:

[0027] 100. Transmitter; 110. Polarizer; 120. First filter; 130. Receiver; 140. Pigtail; 150. Second filter; 160. Housing. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0030] For ease of description, spatial relative terms may be used in the text to describe the relative position or movement of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "front," "back," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure undergoes a positional flip, orientation change, or change of motion, these directional indications will change accordingly. For instance, an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0031] To address the high cost of existing optical devices, this application provides an optical device without an isolator. Through a specific optical path structure design, the optical isolator is eliminated, reducing device manufacturing costs and meeting the application requirements of consumer-grade optical communication products.

[0032] Figure 1 and Figure 2 An optical device without an isolator provided in this application embodiment includes a transmitter 100, a polarizer 110, a first filter 120, a receiver 130, and a pigtail 140. The transmitter 100 is inclined relative to the polarizer 110, the first filter 120 is inclined between the polarizer 110 and the pigtail 140, and the receiver 130 is disposed on the reflected light path of the first filter 120.

[0033] The linearly polarized light emitted from the transmitter 100 is transmitted sequentially through the polarizer 110 and the first filter 120 before being coupled to the pigtail 140.

[0034] The received optical signal recovered from the pigtail 140 is reflected by the first filter 120 and then enters the receiver 130.

[0035] In the above technical solution, the polarizer 110 has the characteristic of selectively transmitting polarized light, and its transmission axis direction determines the polarization direction of the light that is allowed to pass through. By reasonably setting the tilt angle of the emitting end 100 relative to the polarizer 110, it can be ensured that the light component in the linearly polarized light emitted by the emitting end 100 that conforms to the transmission axis direction of the polarizer 110 can pass through smoothly.

[0036] Linearly polarized light that has passed through polarizer 110 continues to propagate and reaches the first filter 120, which is tilted between polarizer 110 and the pigtail. The first filter 120 also operates based on the polarization and wavelength characteristics of light. For linearly polarized light that has passed through polarizer 110, within its specific operating wavelength range, most of the light can pass through the first filter 120 with a certain transmittance and then couple into the pigtail 140. The pigtail 140 serves as a channel for optical signal transmission, guiding the emitted light to other parts of the optical communication system. For example, in an optical module application, the emitted light is transmitted through the pigtail 140 into the optical fiber, thereby achieving long-distance optical signal transmission.

[0037] The received optical signal recovered from the pigtail 140, i.e., the optical signal returning from the other end of the optical communication system, propagates in the opposite direction to the emitted light. When the received optical signal reaches the first filter 120, due to the tilted arrangement of the first filter 120 and its optical characteristics, the received optical signal is reflected by the first filter 120. The reflective characteristics of the first filter 120 cause the received optical signal to change its propagation direction and enter the receiving end 130 located in its reflected optical path.

[0038] The receiver 130 is typically a photodetector, such as a photodiode. When a received optical signal shines on the receiver 130, the energy of the photons is absorbed by the material of the receiver 130, generating electron-hole pairs, thus forming a photocurrent. By detecting and processing the photocurrent, the information carried by the received optical signal can be recovered, thereby realizing the function of receiving optical signals.

[0039] In traditional optical devices without isolators, the optical signal emitted from the transmitter 100 will generate reflected light in the transmission path (such as at the end face of the pigtail, the interface of the filter, etc.). If this reflected light is coupled back to the transmitter 100, it will cause problems such as mode switching, power fluctuation, and shortened lifespan, which will seriously affect the transmission stability of the optical signal.

[0040] The optical device without isolators in this application achieves effective spatial separation of the transmitted and received light through a specific optical path design. Light emitted from the transmitter 100 is coupled to the pigtail 140 after passing through the polarizer 110 and the first filter 120, while the received optical signal is reflected by the first filter 120 and enters the receiver 130. This design makes it difficult for light reflected from components such as the pigtail 140 to couple back to the transmitter 100, thereby effectively suppressing interference from reflected light and improving the stability and reliability of the transmitted light. For example, in some high-speed optical communication systems with extremely high requirements for optical signal quality, using this application can significantly reduce the bit error rate caused by reflected light and improve the system's transmission performance.

[0041] The common approach in current technologies is to connect an optical isolator in series in the transmission optical path of the BOSA to solve the problem of reflected light interference. The optical isolator is a non-reciprocal element based on the Faraday effect. Its core material (such as yttrium iron garnet YIG crystal) and precision manufacturing process result in high cost, which usually accounts for 15%-30% of the total cost of the BOSA.

[0042] The isolator-free optical device of this application eliminates the need for an optical isolator, achieving suppression of reflected light interference through a specific optical path structure design and a rational layout of optical components. This improvement significantly reduces the manufacturing cost of the device, making it more suitable for consumer-grade optical communication products. For example, in cost-sensitive applications such as smart home networks and mobile terminal optical communication, using the isolator-free optical device of this application can reduce the overall cost of the product and improve its market competitiveness.

[0043] Please see Figure 1 In some embodiments of this application, the first filter 120 is tilted toward the pigtail 140 relative to the light-emitting surface of the polarizer 110.

[0044] When linearly polarized light emitted from transmitter 100 is transmitted through polarizer 110, it is directed at a specific angle towards the tilted first filter 120. Because the first filter 120 is tilted towards the pigtail 140, the light transmitted through it can be more precisely coupled into the pigtail 140. This tilting setting adjusts the direction of light propagation, making it more aligned with the axis of the pigtail 140, reducing light loss during coupling, and thus improving the coupling efficiency of the emitted light. For example, in high-speed optical communication systems, improving coupling efficiency ensures that more emitted light can be effectively transmitted into the optical fiber, enhancing signal strength and stability, and reducing the bit error rate.

[0045] When the received optical signal recovered from the pigtail 140 is directed toward the first filter 120, the tilted setting of the first filter 120 can more effectively reflect the received light to the receiver 130. According to the law of reflection of light, a suitable tilt angle can allow the reflected light to accurately enter the photosensitive area of ​​the receiver 130, thereby improving the receiver 130's sensitivity to receiving optical signals.

[0046] In particular, in some embodiments of this application, the tilt angle of the first filter 120 is 45°.

[0047] In addition, the end of the pigtail 140 near the first filter 120 is coated with an anti-reflective film (not shown in the attached figure).

[0048] In optical devices without isolators, when light propagates between pigtail 140 and the first filter 120, reflection occurs at the interface due to the difference in refractive indices between the two media. This reflected light returns along the original path, adversely affecting the performance of the optical device. The main purpose of applying an anti-reflection coating is to reduce light reflection at the interface of pigtail 140 near the first filter 120. Reducing the reflected light at the interface between pigtail 140 and the first filter 120 means that more light can smoothly enter the first filter 120 from pigtail 140 or vice versa. At the transmitter 100, this improves the efficiency of transmitted light coupling into the pigtail, allowing more optical signals to be transmitted into the fiber optic network; at the receiver 130, it increases the intensity of the optical signal returning from the fiber and coupling to the receiver 130, improving receiver sensitivity.

[0049] Please continue reading. Figure 1 This application also includes a second filter 150, which is a 0° incident filter used to filter stray light in the received light. The second filter 150 is disposed on the reflected light path of the first filter 120 and is located between the first filter 120 and the receiving end 130.

[0050] During the operation of an optical device without an isolator, the optical signal received by receiver 130 may contain various stray lights in addition to the desired useful signal light. These stray lights may originate from interference from the external environment, reflections and scattering from other optical components within the optical device, etc. The main function of the second filter 150 is to filter out these stray lights in the received light, allowing only the useful signal light within a specific wavelength range and polarization direction to pass through, thereby improving the quality of the optical signal received by the receiver.

[0051] By filtering out stray light, the interference of noise on the useful signal is reduced, which is equivalent to enhancing the relative strength of the useful signal. This helps to improve the signal-to-noise ratio of the receiver 130, enabling the receiver 130 to detect and identify optical signals more accurately, thereby improving the communication performance and reliability of the entire optical device without an isolator.

[0052] The second filter is designed for 0° incident light, meaning that the light is incident perpendicular to the filter surface. Under this incident method, the direction of light propagation will not change due to the incident angle (ignoring the refraction effect of the filter itself), and the light is filtered only based on the wavelength selection and polarization selection characteristics of the filter.

[0053] When the received light reflected by the first filter 120 is incident on the second filter 150 at 0°, the useful signal light that conforms to the transmission characteristics of the filter can pass through smoothly and reach the receiver 130, while stray light is filtered out.

[0054] Please see Figure 2 In this application, the housing 160 is also included, with the transmitter 100, receiver 130 and pigtail 140 respectively passing through three different surfaces of the housing, and the polarizer 110, the first filter 120 and the second filter 150 fixedly disposed inside the housing 160.

[0055] It should be noted that in this embodiment, the transmitting end 100 is a laser diode and the receiving end 130 is a photodiode. Of course, other laser devices or receiving devices can also be used, and there is no limitation here.

[0056] Furthermore, those skilled in the art should understand that while the optical device described in this application is preferably a 10G optical device, it is equally applicable to optical devices of other rates, such as 25G, 40G, and 100G. Any similar designs employing the inventive concept of this application should fall within the scope of protection of this patent.

[0057] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0058] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0059] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0060] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0061] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0062] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. The illustrative expressions of the above terms in this specification should not be construed as necessarily referring to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0063] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Since these modifications and variations fall within the scope of the claims and their equivalents, this application also intends to include these modifications and variations.

[0064] The above description describes specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An optical device without an isolator, characterized in that, It includes a transmitter, a polarizer, a first filter, a receiver, and a pigtail. The transmitter is tilted relative to the polarizer, the first filter is tilted between the polarizer and the pigtail, and the receiver is disposed on the reflected light path of the first filter. The linearly polarized light emitted from the transmitter is coupled to the pigtail after being transmitted through the polarizer and the first filter in sequence. The received optical signal recovered from the pigtail fiber is reflected by the first filter and then enters the receiving end.

2. The optical device without an isolator according to claim 1, characterized in that, The first filter is tilted toward the pigtail relative to the light-emitting surface of the polarizer.

3. The optical device without an isolator according to claim 1, characterized in that, The tilt angle of the first filter is 45°.

4. The optical device without an isolator according to claim 1, characterized in that, The end of the pigtail fiber closest to the first filter is coated with an anti-reflective film.

5. The optical device without an isolator according to claim 1, characterized in that, It also includes a second filter, which is a 0° incident filter used to filter stray light in the received light. The second filter is disposed on the reflected light path of the first filter and is located between the first filter and the receiving end.

6. The optical device without an isolator according to claim 5, characterized in that, It also includes a housing, with the transmitter, receiver and pigtail respectively passing through three different surfaces of the housing, and the polarizer, first filter and second filter fixedly disposed inside the housing.

7. The optical device without an isolator according to claim 1, characterized in that, The emitting end is a laser diode.

8. The optical device without an isolator according to claim 1, characterized in that, The receiving end is a photodiode.

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