JPS6131929A - Semiconductor spectroscope - Google Patents

Abstract

PURPOSE:To obtain the spectroscope suitable for integration by forming a Fabry-Perot interferometer of a semiconductor light guide on a semiconductor substrate and arranging an input and an output light guide before and behind the interferene system, thus forming the light spectroscope, and varying the refractive index of the semiconductor by the spectroscope. CONSTITUTION:The input and output light guide layers 22 are formed on the low-resistance semiconductor substrate 21. A low-resistance semiconductor clad layer 23, upper and lower electrodes 24 and 25, insulating film 26, and metallic film 27 with a high reflection factor are formed. Thus, the input and output light guides are constituted on the same substrate to realize functions of an optical switch, spectroscope, etc., obtaining a means which serves effectively as part of an optical integrated circuit. The refractive index of the semiconductor waveguide is varied electricaslly to vary its optical path length, and the operation of the spectroscope is realized in an easy integration state by the interference which utilizes reflection at waveguide terminals.

Description

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

Conventional configuration and its problems In recent years, multi-wavelength transmission has attracted attention as optical communication technology has become more sophisticated. For example, in semiconductor lasers, wavelength control using C3 lasers and multi-wavelength light sources using DFB lasers are being realized, making it difficult to miniaturize and identify light emitting elements.

In other words, on the light receiving side, gratings or Fabry-Bello interference systems are often used due to the need for high resolution, resulting in large configurations and difficult handling.

OBJECTS OF THE INVENTION An object of the present invention is to provide a compact and high-resolution semiconductor spectrometer.

Structure of the Invention The present invention forms a Fabry-Bello interference system made up of semiconductor optical waveguides on a semiconductor substrate. However, it is an optical spectrometer in which input/output optical waveguides are arranged before and after the optical spectrometer, and by changing the refractive index of the semiconductor part constituting the interference system, it is favorable and suitable for integration.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a sectional view of a semiconductor spectrometer in a first embodiment.

In FIG. 2, 11 is an n-type semiconductor substrate, 12 is a high-resistance semiconductor optical waveguide layer, 13 is a p-type semiconductor cladding layer,
14.15 are the upper and lower control electrodes, 16
1 is an insulating film, and 17 is a high reflectance metal film. Here, examples of the semiconductor material include InP, GaAs, and the insulating film 16.
For example, SiO2°Si3N4 is considered to be suitable.

The operation of the semiconductor spectrometer configured as described above will be explained below.

The light incident on the leading waveguide layer 12 causes 77 Priebello interference between the high reflectivity metal films 17 at both ends of the waveguide layer. If a voltage is applied between the control electrodes 14 and 15 so as to provide a reverse bias to the pn junction, the optical path length of the waveguide changes. Here, if the wavelength incident into the waveguide is λ, the transmittance of light is maximum when the optical path length is an integral multiple of S. At this time, by changing the applied voltage to change the optical path length within the guide path, only light of a specific wavelength can be passed. Figure 2 shows the refractive index of the waveguide as 3.3.
The thickness of the waveguide layer is 1 μm, the length of the guiding path is 2mm, the reflectance is 0.
9 also shows the dependence of the light transmittance on the applied voltage when the Pockels constant is 1.4×10=2 mV. The parameters include wavelength, and those of λ-1,153 μm and 1.163 μm are shown. In this way, it becomes possible to realize a compact spectrometer with very high resolution. A similar effect can also be obtained by applying a reverse bias to the Schottky barrier as a means of changing the refractive index of the waveguide.

A second embodiment of the present invention will be described below with reference to the drawings. FIG. 3 shows a sectional view of a semiconductor spectrometer showing a second embodiment of the present invention. In the figure, 21 is a low resistance semiconductor substrate, 22 is an optical waveguide layer, 23 is a low resistance semiconductor cladding layer, 24 and 25 are upper and lower electrodes, respectively, 26 is an insulating film, and 27 is a high reflectance metal film. . The difference from the structure shown in FIG. 2 is that the input and output optical waveguides are formed on the same semiconductor substrate. Here, the reflecting surface that becomes the resonator is constructed by etching or the like, but in order to make the end face flat, anisotropic etching or the like is used. By configuring the waveguide and the spectroscopic section on the same substrate as described above, functions such as an optical switch and a spectrometer can be realized, and this is considered to be an effective means for playing a role in an optical integrated circuit.

Effects of the invention By electrically changing the refractive index of a semiconductor optical waveguide, the optical path length can be changed, and by interference using reflection at the end of the waveguide, the function as a spectrometer can be realized in a form that is easy to integrate. .

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a waveguide spectrometer that has a spectrometer function by electrically changing the refractive index of a semiconductor according to the present invention, and Figure 2 is a spectral characteristic of the first embodiment of the present invention. Figure, 3rd
The figure is a sectional view of a second embodiment of the present invention in which input and output waveguides are integrated on the same semiconductor substrate. 11.21... Semiconductor substrate, 12.22...
... Optical waveguide layer, 13, 23... Cladding layer,
14, 15° 24, 25... Control electrode, 16
．． 26...Insulating film, 17, 27...
metal membrane.

Claims (5)

[Claims] (1) A Fabry-Perot resonator consisting of an optical waveguide portion whose refractive index is electrically variable and two high-reflectance reflecting surfaces disposed perpendicular to the waveguide and parallel to each other; 1. A semiconductor spectrometer, comprising: a voltage application section that changes the refractive index of a wavepath section. (2) A semiconductor spectrometer according to claim 1, characterized in that an optical input waveguide and an optical output waveguide are provided on the same semiconductor substrate with the same optical path before and after the semiconductor spectrometer. (3) Semiconductor p-n as a means of electrically changing the refractive index
2. The semiconductor spectrometer according to claim 1, wherein a reverse bias is applied to the junction. (4) The semiconductor spectrometer according to claim 1, characterized in that a Schottky barrier between a semiconductor and a metal is used as means for electrically changing the refractive index. (5) Claim 1, characterized in that current injection into a semiconductor is used as a means to electrically change the refractive index.
Semiconductor spectrometer described in section.