JPS6287933A - Temperature sweeping type semiconductor spectroscope - Google Patents

Abstract

PURPOSE:To adjust face accuracy and an optical axis by using a high reflection factor face using a semiconductor crystal cut surface as a base for a resonance mirror, using an optical waveguide having a light confining function as an optical path, and using the temperature dependency of the refractive index of a semiconductor to change the optical length. CONSTITUTION:A semiconductor material in a GaAs or InP group is used as a material constituting the optical waveguide. Light l1 made incident upon the optical waveguide layer 2 generates Fabry-Perot interference between reflection films 4 on both the ends of the optical waveguide layer 2. When the temperature of the smiconductor constituting the optical waveguide is changed, the refractive index is also changed, so that the optical length is also changed. Consequently, the resonance condition is changed and only the light l2 with a specific wavelength can be transmitted. Thus, a compact and highly efficient spectroscope requiring no optical axis adjustment can be obtained by continuously repeating said temperature change.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a temperature sweep type semiconductor spectrometer having a resonator structure that performs spectroscopy by changing the refractive index of an optical waveguide medium.

BACKGROUND OF THE INVENTION In recent years, as optical communication technology has become more sophisticated, the need for spectroscopic technology has increased. Conventionally, gratings have been commonly used for spectroscopy, but Fabry-Perot interferometers have been used as having higher resolution.

Problems to be Solved by the Invention However, the conventional structure is large, and the resonator surface is made of a quartz plate, etc., making it difficult to adjust the surface accuracy of the resonator surface and the optical axis. There was a problem. Furthermore, in order to change the optical path length, a piezo element must be used to mechanically move the mirror, resulting in a complicated configuration.

Means for Solving the Problems The present invention uses a high reflectivity surface based on a semiconductor crystal valve opening surface as a resonant mirror as a Fabry-Perot resonator7.
In addition, an optical waveguide with an optical confinement function is used as the optical path,
Further, by utilizing the temperature dependence of the refractive index of a semiconductor to change the optical path length, the conventional problems can be solved.

By using the open face of a crystal valve as the mirror of the working resonator, it is easy to obtain a surface with much better surface precision than that achieved by ordinary polishing, and the high-reflection film coating applied to obtain high reflectance achieves high finesse. It is thought that this will work effectively for In addition, the parallelism of both mirrors can be adjusted by using the crystal arm opening plane.
No adjustment is required. Furthermore, by using an optical waveguide that has a light confinement effect as the optical path within the resonator, a spectrometer that is extremely easy to use without shifting the optical axis can be realized. Furthermore, by using the temperature sweep method, the device becomes much simpler and more stable than the conventional piezo sweep type.

Embodiment FIG. 1 is a structural diagram of a semiconductor spectrometer showing an embodiment of the present invention. 1 is a semiconductor substrate serving as a cladding, 2 is a semiconductor optical waveguide layer, 3 is a semiconductor cladding layer, 4 is a reflective film, and 5 is a temperature control device. Here, it is desirable that the optical waveguide be three-dimensionally confined. Furthermore, the material constituting the optical waveguide is generally made of GaAs or InP-based semiconductor materials, but is not particularly limited to these materials.

The operation of the semiconductor spectrometer configured as described above will be explained. The light β1 incident on the optical waveguide layer 2 causes Fabry-Perot interference between the reflective films 40 at both ends of the optical waveguide layer. Here, when the temperature of the semiconductor forming the optical waveguide changes, the refractive index also changes, resulting in a change in the optical path length. This changes the resonance conditions, allowing only the light 12 of a specific wavelength to pass through, and furthermore, by continuously changing the temperature, a spectrometer can be realized. Here, the performance as a Fabry-Perot spectrometer, that is, the free spectral region (F
FIG. 2 shows the optical waveguide length dependence of SR), minimum resolution bandwidth (MRB), and temperature change amount ΔT necessary for spectroscopy, with waveguide end face reflectance R taken as a parameter. Here, the effective refractive index of the optical waveguide is 3.3. A compact spectrometer with much higher resolution can be realized.

Effects of the Invention The temperature sweep type semiconductor spectrometer of the present invention uses a Fabry-Perot resonator using a semiconductor optical waveguide and its valve opening, thereby creating a compact and high-performance spectrometer that does not require optical axis adjustment. Since it can be realized and is made of a semiconductor material, it is considered possible to apply it to optical/electronic integrated circuits, etc.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a temperature sweep type semiconductor spectrometer according to an embodiment of the present invention, and Figure 2 is a diagram showing the optical waveguide length dependence of the spectral range, resolution, and amount of temperature change required for spectroscopy of the spectrometer of this embodiment. FIG. 3 is a characteristic diagram showing the characteristics (waveguide end face reflectance is a parameter). DESCRIPTION OF SYMBOLS 1... Semiconductor substrate, 2... Optical waveguide layer, 3... Semiconductor cladding layer, 4... Reflective film, 6... Temperature Control device. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
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Claims (1)

[Claims] A Fabry-Perot resonator comprising a semiconductor optical waveguide whose refractive index changes with temperature changes, two high-reflectance reflective surfaces arranged perpendicular to the waveguide and parallel to each other, and the optical waveguide section. A temperature sweep type semiconductor spectrometer comprising: a temperature control section for changing the refractive index of the semiconductor spectrometer.