Monitoring device for output power of tunable laser

Abstract

The utility model discloses a monitoring device for tunable laser output power, a diffraction grating is arranged on a light path of emergent light of a laser, the emergent light of the laser is reflected by the diffraction grating to form first-order diffracted light and zero-order diffracted light, and the monitoring device is characterized by comprising a light receiver, the light receiver is arranged on a light path of the zero-order diffracted light, and the light receiver receives the zero-order diffracted light. According to the utility model, the photoelectric sensor is arranged outside the laser, so that the photoelectric sensor for monitoring is separated from the laser, air (or a reflecting mirror) is used for transmitting light, media such as optical fibers are not needed, and the photoelectric sensor can be suitable for various types of lasers by adopting the non-contact installation; meanwhile, the photoelectric sensor is arranged outside the laser, the technical difficulty is reduced, and the cost is reduced.

Description

Technical Field

[0001] The utility model relates to the field of semiconductor lasers, and more specifically to a monitoring device for the output power of a tunable laser. Background Art

[0002] A tunable laser is a semiconductor laser that has the ability to adjust the output wavelength. This laser is usually constructed from semiconductor materials, and the wavelength can be tuned by adjusting parameters such as current or temperature. The application areas of tunable semiconductor lasers are very wide, and their wavelength tunability and performance characteristics make them an important tool in the fields of optics and optoelectronics. With the continuous advancement of technology, the application of tunable semiconductor lasers in various fields is also expanding. The main application areas include optical fiber communications, spectral analysis, optical sensing, optical imaging, optical testing and calibration, etc.

[0003] The stable output power of a tunable laser is a key feature to ensure that the laser output is consistent and predictable over time. This is very important for many applications such as fiber optic communications, spectroscopy, optical imaging, and laser processing.

[0004] The working principle of tunable external cavity laser is based on the external cavity reflection grating or other tunable elements, which enables the output wavelength of the laser to be continuously tuned within a certain range.

[0005] Here is how a tunable external cavity laser works:

[0006] Laser diode (LD): The core of the tunable external cavity laser is a laser diode (LD), which is usually used to generate the initial lasing light. The laser diode is usually made of semiconductor materials and has a fixed wavelength output;

[0007] External cavity reflection grating or mirror: An important component of the external cavity laser is a tunable reflection grating or mirror, which is usually located at the output of the laser diode. This tunable element allows the selective reflection or refracting of specific wavelengths of light.

[0008] External cavity reflection: After the light emitted by the laser diode passes through the external cavity reflection grating or lens, part of the light is reflected back to the laser diode. This part of the reflected light is the first-order diffraction light, and part of the light escapes from the external cavity. This part of the light escaping from the external cavity is the zero-order diffraction light; the specific wavelength of the reflected light is adjusted by the external cavity structure so that it is fed back to the laser diode.

[0009] Wavelength tuning: By fine-tuning the angle or position of the external cavity reflection grating or mirror, the reflected wavelength can be changed, thereby tuning the wavelength of the output laser. This enables the tunable external cavity laser to achieve continuous wavelength tuning within a certain range.

[0010] Output laser: The tuned light forms a laser output after passing through a reflective grating or lens. This laser output has a tunable wavelength and can be used in various applications such as fiber optic communications, spectral analysis, optical imaging, etc.

[0011] In general, tunable external cavity lasers achieve wavelength tuning by changing the position of a reflective grating or mirror in the external cavity to selectively direct light of a specific wavelength back into the laser diode.

[0012] The feedback control system is one of the key factors to ensure the stable output power of the tunable laser. The feedback control system is used to monitor the output power of the laser and adjust the current or other parameters as needed to maintain a constant output power.

[0013] In the prior art, in order to adjust the output power in real time based on feedback, a back reflection monitoring photoelectric sensor is integrated inside the laser. However, due to the limited volume inside the laser, this technology is difficult to integrate, has high cost, and cannot be applied to multiple types of lasers. Utility Model Content

[0014] Features and advantages of the invention are set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

[0015] In order to solve the problem that the prior art integrates a photoelectric sensor inside the laser, resulting in high cost and inability to adapt to various types of lasers, the utility model provides a monitoring device for tunable laser output power, in which the photoelectric sensor is arranged outside the laser, thereby reducing costs and being applicable to various types of lasers.

[0016] The technical solution adopted by the utility model to solve the above-mentioned technical problems is as follows: a monitoring device for the output power of a tunable laser, a diffraction grating is provided on the optical path of the laser's emitted light, the laser's emitted light forms first-order diffraction light and zero-order diffraction light after being reflected by the diffraction grating, the monitoring device comprises an optical receiver, the optical receiver is provided on the optical path of the zero-order diffraction light, and the optical receiver receives the zero-order diffraction light.

[0017] The monitoring device further includes a first reflecting element, which is disposed on the optical path of the zero-order diffraction light and reflects the zero-order diffraction light onto the optical receiver.

[0018] The light receiver is a photoelectric sensor.

[0019] The first reflecting element is a reflecting mirror.

[0020] A collimating lens is arranged at the front end of the laser, and the emitted light of the laser is converged into parallel light by the collimating lens and then projected onto the diffraction grating.

[0021] A second reflector is provided on the optical path of the first-order diffracted light, and the second reflector is used to reflect the first-order diffracted light back to the diffraction grating.

[0022] The second reflecting element is a reflecting mirror.

[0023] The utility model arranges a photoelectric sensor outside the laser so that the monitoring photoelectric sensor and the laser are separated, uses air (or a reflector) to propagate light, and does not require media such as optical fibers. This non-contact installation enables the photoelectric sensor to be applicable to various types of lasers. At the same time, the photoelectric sensor is arranged outside the laser, which reduces technical difficulty and costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be described in detail below with reference to the accompanying drawings and in combination with examples, and the advantages and implementation methods of the present invention will become more obvious. The contents shown in the accompanying drawings are only used to explain the present invention and do not constitute any limitation to the present invention. In the accompanying drawings:

[0025] Figure 1 The optical path principle between the laser and the monitoring device in the utility model Figure 1 ;

[0026] Figure 2 The optical path principle between the laser and the monitoring device in the utility model Figure 2 . DETAILED DESCRIPTION

[0027] like Figure 1 and Figure 2 As shown, in the monitoring device for the output power of a tunable laser proposed in the embodiment of the utility model, a diffraction grating 3 is provided on the optical path of the emitted light of the laser 1, and a collimating lens 2 is provided at the front end of the laser 1. The emitted light of the laser 1 is converged into parallel light by the collimating lens 2 and then emitted onto the diffraction grating 3.

[0028] The emitted light of the laser 1 is reflected by the diffraction grating 3 to form the first-order diffraction light 8 and the zero-order diffraction light 7. The monitoring device 100 includes a light receiver. In this embodiment, the light receiver 6 is a photoelectric sensor. The photoelectric sensor is arranged on the optical path of the zero-order diffraction light 7, and the photoelectric sensor receives the zero-order diffraction light 7. When the laser is working, the zero-order diffraction enters the photoelectric sensor, and the photoelectric sensor converts the incident light into an electrical signal, and the current laser intensity is fed back by monitoring the signal intensity.

[0029] Firstly, the utility model sets a photoelectric sensor outside the laser so that the monitoring photoelectric sensor and the laser are separated, and uses air (or a reflector) to propagate light, and does not require a medium such as an optical fiber. By adopting this non-contact installation, the photoelectric sensor can be applied to various types of lasers. At the same time, the photoelectric sensor is set outside the laser, which reduces the technical difficulty and the cost. Secondly, the integrated type in the prior art generally relies on hardware circuits to adjust the output intensity according to the feedback signal. The sensitivity of the circuit is fixed when it leaves the factory. However, the utility model sets a photoelectric sensor outside the laser, and can design feedback circuits with different sensitivities by itself to achieve different precision control. Finally, the stronger the output light, the stronger the corresponding feedback signal. If the drive circuit has an incorrect configuration, it will cause the circuit output to be too large. The circuit implemented by hardware cannot directly cut off the drive output. The photoelectric sensor is set outside the laser and a separate setting is adopted. The drive power supply can be cut off after the feedback intensity exceeds the safety threshold through software judgment.

[0030] The monitoring device further includes a first reflector 5, which is disposed on the optical path of the zero-order diffraction light 7 and reflects the zero-order diffraction light 7 onto the photoelectric sensor. In this embodiment, the first reflector 5 is a reflector.

[0031] After the installation position of the photoelectric sensor is determined, the angle of the first reflector 5 is adjusted to reflect the zero-order diffraction light 7 reflected by the diffraction grating 3 into the photosensitive surface of the photoelectric sensor. The purpose of setting the first reflector is to make the installation position of the photoelectric sensor more flexible. If there is no restriction on the installation position of the photoelectric sensor, the first reflector may not be set.

[0032] A second reflector 4 is provided on the optical path of the first-order diffracted light 8, and the second reflector 4 is used to reflect the first-order diffracted light 8 back to the diffraction grating 3, to resonate and excite the laser. In this embodiment, the second reflector is a reflector.

[0033] The preferred embodiments of the present invention are described above with reference to the accompanying drawings. A person skilled in the art may implement the present invention in a variety of variations without departing from the scope and essence of the present invention. For example, a feature shown or described as part of one embodiment may be used in another embodiment to obtain another embodiment. The above are only preferred feasible embodiments of the present invention, and do not limit the scope of rights of the present invention. Any equivalent changes made using the contents of the present invention specification and the accompanying drawings are included in the scope of rights of the present invention.

Claims

1. A monitoring device for the output power of a tunable laser, wherein a diffraction grating (3) is provided on the optical path of the emitted light of the laser (1), and the emitted light of the laser (1) is reflected by the diffraction grating (3) to form first-order diffraction light (8) and zero-order diffraction light (7), characterized in that: The monitoring device (100) comprises a light receiver (6), wherein the light receiver (6) is arranged on the optical path of the zero-order diffraction light (7), and the light receiver (6) receives the zero-order diffraction light (7).

2. The device for monitoring the output power of a tunable laser according to claim 1, characterized in that: The monitoring device (100) further comprises a first reflecting element (5), which is arranged on the optical path of the zero-order diffraction light (7) and reflects the zero-order diffraction light (7) onto the optical receiver (6).

3. The device for monitoring the output power of a tunable laser according to claim 1, characterized in that: The light receiver (6) is a photoelectric sensor.

4. The device for monitoring the output power of a tunable laser according to claim 2, characterized in that: The first reflecting element (5) is a reflecting mirror.

5. The device for monitoring the output power of a tunable laser according to claim 1, characterized in that: A collimating lens (2) is provided at the front end of the laser (1), and the emitted light of the laser (1) is converged into parallel light by the collimating lens (2) and then emitted onto the diffraction grating (3).

6. The device for monitoring the output power of a tunable laser according to claim 1, characterized in that: A second reflector (4) is provided on the optical path of the first-order diffraction light (8), and the second reflector (4) is used to reflect the first-order diffraction light (8) back to the diffraction grating (3).

7. The device for monitoring the output power of a tunable laser according to claim 6, characterized in that: The second reflecting element (4) is a reflecting mirror.

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