Single-tube superluminescent diode ultra-broadband light source based on wavelength division multiplexing and coupling technology

Abstract

The present invention relates to a single-tube three-chip superluminescent diode ultra-wideband light source based on wavelength division multiplexing technology in the technical field of semiconductor optoelectronic devices, comprising three groups of SLED chips and collimating lenses, two wavelength division multiplexing filters and one output optical fiber collimator. The three collimating lenses are respectively on the light-emitting sides of the three SLED chips to form three beams of parallel light. The planes where the end faces of the two wavelength division multiplexing filters are located are at an angle of 45 degrees to the optical axis of the first SLED light beam, while the plane where the other end face of the first wavelength division multiplexing filter is located is at an angle of 45 degrees to the optical axis of the second SLED light beam, and the plane where the other end face of the second wavelength division multiplexing filter is located is at an angle of 45 degrees to the optical axis of the third SLED light beam. The present invention adopts wavelength division multiplexing technology, and three SLED chips share a set of TEC temperature control chips, which reduces the volume of an ultra-wideband light source using conventional technology, reduces the complexity of the temperature control circuit and the SLED drive circuit, improves the performance and stability of the light source, and has a wide range of practical value.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor optoelectronic devices, and in particular to a single-tube superluminescent diode ultra-wideband light source based on wavelength division multiplexing and coupling technology. Background Art

[0002] Optical Coherence Tomography technology has been widely used in the fields of medical treatment, sensing, and beauty, and an important optoelectronic device in the OCT imaging system is the super-luminescent light emitting diode (SLED). Different application ranges have different requirements for the indicators of the SLED emission light source. For example, the short wavelength of 750-900nm is often used in the OCT system for fundus examination in ophthalmology, while the long-wave band of 1310nm and 1550nm is used in gastrointestinal, cardiac and other medical examinations and industrial detection OCT systems. The wider the spectrum of the SLED light source, the higher the resolution of the OCT imaging. Therefore, how to find SLED devices with stable output light power performance and broadband spectrum has always been the key to the development of high-resolution OCT systems.

[0003] Limited by the current chip development technology, the emission spectrum 3dB bandwidth of the conventional short-wavelength window (800-900nm) SLED device chip is only 40-50nm. In the application of high-resolution OCT system, SLED emission light source devices with ultra-wideband spectrum greater than 100nm are often required to obtain higher system detection resolution. In order to achieve ultra-wideband spectral bandwidth, the method of photosynthesis is usually adopted to combine multiple SLED devices of different wavelengths through a passive optical beam combiner to combine light beams of different wavelengths, thereby obtaining a wider spectrum. Figure 1 It is the commonly used 3 SLED devices and 2 fiber combiners ( Figure 1 ) and 2 SLED devices and 1 fiber combiner ( Figure 2 ) Technical solutions for realizing ultra-wideband light sources. Since these technical solutions all use separate optical devices, generally fiber-optic optical devices, the ultra-wideband light sources realized are large in size and difficult to miniaturize; there are many fiber connection points, resulting in large light losses; and the cost is high, with as many as five optical devices alone; and the control is difficult, requiring temperature and current control for three or two independent SLED devices, which increases the complexity of the circuit. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a single-tube superluminescent diode ultra-wideband light source based on wavelength division multiplexing and coupling technology, aiming to solve the technical problems of large size, high loss, high cost and difficult control of ultra-wideband light source solutions in the prior art.

[0005] The single-tube superluminescent diode ultra-wideband light source based on wavelength division multiplexing and coupling technology provided by the present invention has the following specific technical solutions:

[0006] A single-tube superluminescent diode ultra-wideband light source based on wavelength division multiplexing and coupling technology comprises a first SLED chip, a second SLED chip, a first collimating lens, a second collimating lens and a first wavelength division multiplexing filter, wherein the first collimating lens is located on the light-emitting side of the first SLED chip, the second collimating lens is located on the light-emitting side of the second SLED chip, the angle between the plane where one end face of the first wavelength division multiplexing filter is located and the optical axis of the first collimating lens is 44-46 degrees, and the angle between the plane where the other end face of the first wavelength division multiplexing filter is located and the optical axis of the second collimating lens is 44-46 degrees.

[0007] In an embodiment, it further includes a third SLED chip, a third collimating lens and a second wavelength division multiplexing filter, the third collimating lens is located on the light-emitting side of the third SLED chip, the angle between the plane where one end surface of the second wavelength division multiplexing filter is located and the optical axis of the first collimating lens is 44-46 degrees, and the angle between the plane where the other end surface of the second wavelength division multiplexing filter is located and the optical axis of the third collimating lens is 44-46 degrees.

[0008] In an embodiment, it also includes a tube shell, a TEC temperature control chip and a heat sink, the tube shell is a cavity, the TEC temperature control chip is mounted on the inner bottom surface of the cavity with the cold surface of the TEC temperature control chip facing upward, the heat sink is fixed on the cold surface of the TEC temperature control chip, the first SLED chip, the second SLED chip and the third SLED chip are fixed on the heat sink through a transition heat sink; the first collimating lens, the second collimating lens, the third collimating lens, the first wavelength division multiplexing filter and the second wavelength division multiplexing filter are all fixed on the heat sink.

[0009] In an embodiment, a PD detector chip assembly and a thermistor assembly are also included, wherein the PD detector chip assembly includes a PD detector chip and a ceramic insulating gasket, and the PD detector chip is mounted on the ceramic insulating gasket; the thermistor assembly includes a thermistor and a ceramic gasket, and the thermistor is mounted on the ceramic gasket; and both the PD detector chip assembly and the thermistor assembly are mounted on the heat sink.

[0010] In an embodiment, a fiber collimator is further included, and the fiber collimator is installed on the side of the tube shell. The angle between the plane where the other end face of the second wavelength division multiplexing filter is located and the optical axis of the fiber collimator is 134-136 degrees.

[0011] In an embodiment, the fiber collimator comprises a focusing lens and an output fiber, the output fiber being located at a focusing point of the focusing lens.

[0012] The present invention has the following beneficial effects: the single-tube superluminescent diode ultra-wideband light source proposed by the present invention adopts the technology of wavelength division multiplexing filter and spatial coupling, and two or more SLED chips can be assembled inside the tube shell that previously assembled one SLED chip, and the multiple SLED chips share a set of temperature detection and temperature control (TEC temperature control chip), so as to realize an ultra-wideband light source of multiple SLED chips in a single tube, greatly reduce the volume of such ultra-wideband light source using conventional optical fiber beam combining technology, greatly reduce the complexity of conventional temperature control circuit and SLED driving circuit, improve the performance and stability of SLED devices, and have very wide practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the structure of an ultra-wideband light source using three SLED devices and two fiber combiners in the prior art;

[0014] Figure 2 It is a schematic diagram of the structure of an ultra-wideband light source using two SLED devices and one optical fiber combiner in the prior art;

[0015] Figure 3 It is a schematic diagram of the wavelength division and beam combining optical paths of three SLED chips of the single-tube superluminescent diode ultra-wideband light source based on wavelength division multiplexing and coupling technology provided by the present invention;

[0016] Figure 4 It is the transmission characteristic curve of the first wavelength division multiplexing filter coating at 45 degrees, and the reflection characteristic R = 1-T;

[0017] Figure 5 It is the transmission characteristic curve of the second wavelength division multiplexing filter coating at 45 degrees, and the reflection characteristic R=1-T;

[0018] Figure 6 is the anti-reflection coating characteristic curve of the first and second wavelength division multiplexing filters;

[0019] Figure 7 It is an internal assembly diagram of a tube shell of a single-tube superluminescent diode ultra-wideband light source based on wavelength division multiplexing and coupling technology provided by the present invention;

[0020] Figure 8is a schematic diagram of a photosynthetic beam of the first SLED chip and the second SLED chip after transmission and reflection through the first wavelength division multiplexing filter;

[0021] Fig. 9 It is a schematic diagram of the photosynthetic beam of the first SLED chip, the second SLED chip and the third SLED chip after transmission and reflection through the second wavelength division multiplexing filter. DETAILED DESCRIPTION

[0022] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0023] The single-tube superluminescent diode ultra-wideband light source based on wavelength division multiplexing and coupling technology provided by the present invention has the following specific technical solutions:

[0024] Single tube superluminescent diode ultra-broadband light source based on wavelength division multiplexing and coupling technology, such as Figure 3 As shown, it includes a first SLED chip 1, a second SLED chip 2, a first collimating lens 3, a second collimating lens 4 and a first wavelength division multiplexing filter 5. The first collimating lens 3 is located on the light-emitting side of the first SLED chip 1, and the second collimating lens 4 is located on the light-emitting side of the second SLED chip 2. The angle between the plane where one end face of the first wavelength division multiplexing filter 5 is located and the optical axis of the first collimating lens 3 is 45±1 degrees, and the angle between the plane where the other end face of the first wavelength division multiplexing filter 5 is located and the optical axis of the second collimating lens 4 is 45±1 degrees. In this embodiment, it also includes a third SLED chip 6, a third collimating lens 7 and a second wavelength division multiplexing filter 8. The third collimating lens 7 is located on the light-emitting side of the third SLED chip 6. The angle between the plane where one end face of the second wavelength division multiplexing filter 8 is located and the optical axis of the first collimating lens 3 is 45±1 degrees, and the angle between the plane where the other end face of the second wavelength division multiplexing filter 8 is located and the optical axis of the third collimating lens 7 is 45±1 degrees. The wavelength range of the first SLED chip 1 is 860nm-920nm, the wavelength range of the second SLED chip 2 is 800nm-850nm, and the wavelength range of the third SLED chip 6 is 780nm-800nm. The first collimating lens 3, the second collimating lens 4 and the third collimating lens 7 are used to convert the non-collimated light beam output by the SLED chip into a parallel light beam for spatial coupling. The first wavelength division multiplexing filter 5 has Figure 4The optical filtering characteristics are as follows: its transmittance (Ta) for a light beam with a wavelength of 865 to 1000 nm is greater than 95%, so that the parallel light of the first SLED chip 1 passing through the first collimating lens 3 can basically pass through the first wavelength division multiplexing filter 5; its reflectivity (Ra) for a light beam with a wavelength of 780 to 845 nm is greater than 98%, so that the parallel light of the second SLED chip 2 after passing through the second collimating lens 4 is basically reflected by the first wavelength division multiplexing filter 5. The second wavelength division multiplexing filter 8 has Figure 5 The optical filtering characteristics are as follows: the transmittance (Ta) of the light beam with a wavelength of 815-960nm is greater than 95%, so that the collimated light beams of the first SLED chip 1 and the second SLED chip 2 can basically pass through the second wavelength division multiplexing filter 8; the reflectance (Ra) of the light beam with a wavelength of 770-795nm is greater than 98%, so that the light beam of the third SLED chip 6 after passing through the third collimating lens 7 is basically reflected by the second wavelength division multiplexing filter 8. Figure 6 The anti-reflection coating characteristic curves of the first and second wavelength division multiplexing filters are shown. The anti-reflection coating reduces the reflection of the wavelength division multiplexing filter, which can minimize the loss of each beam of light passing through the wavelength division multiplexing filter, and also reduces the influence of reflection on the light output of the SLED chip.

[0025] In this embodiment, if Figure 7 As shown, it also includes a tube shell 9, a TEC temperature control chip 10 and a heat sink 11. The tube shell 9 is a cavity, and the TEC temperature control chip 10 is installed on the inner bottom surface of the cavity, and the cold surface of the TEC temperature control chip 10 faces upward. The heat sink 11 is fixed on the cold surface of the TEC temperature control chip 10, and the first SLED chip 1, the second SLED chip 2 and the third SLED chip 6 are fixed on the heat sink 11 through the transition heat sink 12, and the first collimating lens 3, the second collimating lens 4, the third collimating lens 7, the first wavelength division multiplexing filter 5 and the second wavelength division multiplexing filter 8 are all fixed on the heat sink 11. In this way, the first SLED chip 1, the second SLED chip 2, and the third SLED chip 6 use a set of temperature detection and temperature control (TEC temperature control chip 10) to realize a single-tube SLED ultra-wideband light source.

[0026] In this embodiment, a PD detector chip assembly and a thermistor assembly are also included. The PD detector chip assembly includes a PD detector chip 14 and a ceramic insulating gasket 16. The PD detector chip is mounted on the ceramic insulating gasket. The thermistor assembly includes a thermistor 13 and a ceramic gasket 15. The thermistor is mounted on the ceramic gasket. The PD detector chip assembly and the thermistor assembly are both mounted on a heat sink 11. On the optical path side after the wavelength division and beam combining, the installed PD detector chip 14 can easily monitor the total optical power output, which is conducive to realizing optical signal feedback control.

[0027] In this embodiment, a fiber collimator is also included. The fiber collimator is inserted on the side of the tube shell 9. The angle between the plane where the other end face of the first wavelength division multiplexing filter 5 is located and the optical axis of the fiber collimator is 135 degrees. The fiber collimator includes a focusing lens 17 and an output optical fiber 18. The output optical fiber 18 is located at the focusing point of the focusing lens 17. The parallel light beams of the first SLED chip 1, the second SLED chip 2, and the third SLED chip 6 are finally wavelength-division multiplexed and coupled to the output optical fiber 18 through the focusing lens 17.

[0028] In summary, the working principle of the present invention is as follows: the parallel light of the first SLED chip 1 after passing through the first collimating lens 3 passes through the first wavelength division multiplexing filter 5, and the parallel light of the second SLED chip 2 after passing through the second collimating lens 4 is reflected by the first wavelength division multiplexing filter 5, and the transmitted light beam of the first SLED chip 1 and the reflected light beam of the second SLED chip 2 are spatially coupled to form a combined light beam, and Figure 1 , 2 Compared with the fiber combiner method shown in the figure, the loss is much smaller, because the fiber combiner has a 3dB attenuation in theory, that is, at least 50% of the light cannot pass through the fiber combiner. In addition, spatial coupling greatly reduces the space occupied by the coupling device, effectively reducing the volume. Figure 8 The spectrum of the first SLED chip 1 after passing through the first collimating lens 3 and the second SLED chip 2 after passing through the second collimating lens 4, and after being transmitted and reflected through the first wavelength division multiplexing filter 5. The light beams after wavelength division multiplexing of the first SLED chip 1 and the second SLED chip 2 are transmitted through the second wavelength division multiplexing filter 8. The light beam of the third SLED chip 6 after passing through the third collimating lens 7 is reflected by the second wavelength division multiplexing filter 8 and wavelength division multiplexed with the transmitted light beam. The parallel light beams of the first SLED chip 1, the second SLED chip 2, and the third SLED chip 6 are finally wavelength division multiplexed and coupled to the output optical fiber 18 through the focusing lens 17, and finally output as shown in FIG. Fig. 9 Due to the wavelength division multiplexing and spatial coupling technology, it is possible to assemble all SLED chips, lenses and wavelength division multiplexing filters in a tube shell 9 with a size similar to that of a single SLED device, thus realizing ultra-wideband single-tube SLED packaging.

[0029] According to the specific requirements for the output bandwidth and optical power of the light source and the performance of the SLED chip, the wavelength division multiplexing technology of the present invention is also applicable to the structure of two SLED chips and four SLED chips to realize a single-tube superluminescent diode ultra-wideband light source, which only requires adding or reducing some optical devices and modifying the wavelength division multiplexing filter design.

[0030] The above are only preferred embodiments of the present invention, and are not intended to limit the present invention. The present invention is not limited to the above examples. Any changes, modifications, additions or substitutions made by those skilled in the art within the spirit and scope of the present invention shall also fall within the protection scope of the present invention.

Claims

1. A single-tube superluminescent diode ultra-wideband light source based on wavelength division multiplexing and coupling technology, characterized in that: The invention comprises a first SLED chip, a second SLED chip, a first collimating lens, a second collimating lens, and a first wavelength division multiplexing filter, wherein the first collimating lens is located at the light-emitting side of the first SLED chip, the second collimating lens is located at the light-emitting side of the second SLED chip, the angle between the plane where one end face of the first wavelength division multiplexing filter is located and the optical axis of the first collimating lens is 44-46 degrees, and the angle between the plane where the other end face of the first wavelength division multiplexing filter is located and the optical axis of the second collimating lens is 44-46 degrees; It also includes a third SLED chip, a third collimating lens and a second wavelength division multiplexing filter, wherein the third collimating lens is located on the light-emitting side of the third SLED chip, the angle between the plane where one end surface of the second wavelength division multiplexing filter is located and the optical axis of the first collimating lens is 44-46 degrees, and the angle between the plane where the other end surface of the second wavelength division multiplexing filter is located and the optical axis of the third collimating lens is 44-46 degrees; The optical fiber also includes a tube shell, a TEC temperature control chip and a heat sink, wherein the tube shell is a cavity, the TEC temperature control chip is mounted on the inner bottom surface of the cavity with the cold surface of the TEC temperature control chip facing upward, the heat sink is fixed on the cold surface of the TEC temperature control chip, the first SLED chip, the second SLED chip and the third SLED chip are fixed on the heat sink through a transition heat sink; the first collimating lens, the second collimating lens, the third collimating lens, the first wavelength division multiplexing filter and the second wavelength division multiplexing filter are all fixed on the heat sink; It also includes a fiber collimator, which is installed on the side of the tube shell. The angle between the plane where the other end surface of the second wavelength division multiplexing filter is located and the optical axis of the fiber collimator is 134-136 degrees.

2. The single-tube superluminescent diode ultra-wideband light source based on wavelength division multiplexing and coupling technology according to claim 1 is characterized in that: It also includes a PD detector chip assembly and a thermistor assembly, the PD detector chip assembly includes a PD detector chip and a ceramic insulating gasket, the PD detector chip is mounted on the ceramic insulating gasket, the thermistor assembly includes a thermistor and a ceramic gasket, the thermistor is mounted on the ceramic gasket, and the PD detector chip assembly and the thermistor assembly are both mounted on the heat sink.

3. The single-tube superluminescent diode ultra-wideband light source based on wavelength division multiplexing and coupling technology according to claim 1 is characterized in that: The optical fiber collimator comprises a focusing lens and an output optical fiber, wherein the output optical fiber is located at a focusing point of the focusing lens.

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