JPS61149906A - Optical wavelength demultiplexing device - Google Patents

Abstract

PURPOSE:To facilitate optical axis adjustments by forming a BPF on two mutually parallel flanks for arraying which have a specific angle to the reference surface of a polygonal prism, and arraying and fixing plural optical fiber collimators mechanically on the flanks for arraying for the reference surface. CONSTITUTION:Light which is propagated in an optical fiber 1a and includes wavelengths lambda1-lambda4 is converted by an optical fiber collimator 12a into parallel luminous flux, which is incident on a BPF3. The BPF3 transmits only light of wavelength lambda1 to an optical fiber collimator 12b while reflecting the remaining light. The reflected light of lambda2, lambda3, and lambda4 is reflected by a mirror 11 to enter a BPF4. The BPF4 transmits only light of wavelength lambda2 to an optical fiber collimator 12c while reflecting the light of other wavelengths. At this time, the pitch P of light reflected repeatedly in a polygonal prism 7 is equal to the pitch D of the optical axes of the respective fiber collimators, so light beams of wavelengths lambda3 and lambda4 are demultiplexed similarly. Thus, optical axis adjustments and assembly are performed through simple operation.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an optical wavelength demultiplexing device, and in particular, it separates light of a plurality of different wavelengths propagating through one optical transmission line, respectively. It has the function of separating into different transmission paths. This invention relates to an optical wavelength demultiplexing device using a bandpass interference filter.

[Conventional technology]

FIG. 3 shows a wavelength-multiplexing device as an example of a conventional optical wavelength demultiplexing device using an interference filter. In the figure, the end face of each party fiber r/a)(zb)(lc)(/dM/e) is
Lenses (Co a) (2b”) (Co c) (Co d) (
It is installed at the focal point of the center (Koshima). Interference filter (3
)(*] (tl (6) is the wavelength λl and λshima λ, respectively.
This is a bandpass interference filter (hereinafter referred to as BPF) that transmits only light of wavelengths J and λq and reflects light of other wavelengths, and is installed at an angle with respect to the incident light. The wave characteristics of these interference filters change depending on the angle of incidence of the light beam, so in order to obtain uniform characteristics, the light with wavelengths λl to λ emitted from the optical fiber (ia) is passed through the lens (λa). It is converted into a parallel light beam and enters the first B P F (,7). Here, B P F (, 71 transmits only the light of wavelength λl and reflects the light of other wavelengths. Therefore, only the light of wavelength λl is condensed by the lens (cob) and connected to the optical fiber (
tb), and the other wavelength λ col λ Hironoko is incident on the second B
It is incident on P F (4t). Here B P F(lI)
transmits only light of wavelength λ and reflects light of other wavelengths.

Therefore, only the light of wavelength λ is condensed by the lens (λC) and enters the optical fiber (/C), and the light of other wavelengths λJ, λ
The first light enters the third B P F (7117 people). In the same way, the light of wavelength λJ is sequentially transmitted through the optical fiber (/d).

Light having a wavelength of λ enters an optical fiber (re) and is demultiplexed.

In the above device, optical fibers (ta) to (ie),
Lens (J a ) ~ (2e), B P F (J
) - (61 are arranged independently and distributed in a cold space.1 For example, in order to efficiently couple the light of wavelength λ emitted from the optical fiber (ia) to the optical fiber (le). is the lens (a
a)-BPF (,7XaXjXa), lens (2e)
.

It is necessary to adjust the optical axis by moving each optical fiber (te') independently. Furthermore, all of the light with a wavelength of λ/-%-λ can be efficiently transmitted through optical fibers (ia) to (ie).
If you try to couple it to the optical axis, the optical axis adjustment becomes complicated.

In addition, we are busy adjusting the optical axis of the optical fiber, and each wavelength λ
Prepare light sources from l to λq and check the amount of light coupling for each.ff
I went there while drinking 1l+.

Furthermore, the end faces of each lens and each fiber are not aligned with each other and are arranged in different stages.

Assembling and fixing each part becomes complicated, and.

There is a lot of wasted space.

[Problem that the invention seeks to solve]

In the conventional optical wavelength demultiplexing device as described above, when adjusting the optical axis, a light source for each demultiplexed wavelength is prepared, and the lenses (2a) to
(2e), BPF [3) ~ (A), optical fiber (
Since adjustments are made while observing the light coupling t by moving each of ta) to (/θ), the work is extremely complicated, and the assembly and fixing of each part is complicated, requiring wasted space. There was a problem.

This invention was made to solve such problems, and eliminates the complicated optical axis adjustment F'1: I7. Optical axis fA and assembly can be done easily and easily.

The purpose is to obtain an optical wavelength demultiplexing device without wasted space.

[Means for solving problems]

The optical wavelength demultiplexing device according to the present invention uses a polygonal prism having λ alignment side surfaces that are parallel to each other and make a certain angle with a reference plane, and a bandpass interference filter is formed on the alignment side surfaces, and a bandpass interference filter is formed on the alignment side surfaces. A plurality of optical shear collimators are mechanically aligned and fixed with respect to a reference plane on the side surface.

[For production]

In this invention, the alignment side 111 of the polygonal prism
kW, and optical axis adjustment and assembly are performed by a simple operation of mechanically aligning the optical fiber collimator to a reference plane in a constant manner.

〔Example〕

Figure 1 shows an embodiment of the present invention, with symbols r/a) to (
1e), (J) to (6) are the same or equivalent parts as in FIG. (ri) is a polygonal prism, and (za) is an angle (θ) with respect to the polygon. Side for alignment (?)
A mirror (11) made of a metal film is formed on , and the other alignment side surface (to) K is made of an at-body interference filter film B.
P p(,y)@+l are formed in order. (1 core a) (/co b) (t2c) (lJa) (lJa ) is an optical fiber collimator, and the cylindrical sleeve (t
ya) (tJb) (tsc) (/JdM/Je), optical fiber terminals (ta) to (te) and gradient index lens (i41a>(1)Ab)(/!Ic')(ia
6) Each pair of (ta@) is connected to each other and incorporated therein. Here, the optical fiber collimator (lJa) ~ (
The light emitted from the cylindrical sleeves (/, 3a) to (tye) is assembled so that the light emitted from the cylindrical sleeves (/, 3a) to (tye) coincide with the central axes of the parallel light beams. (/j3)
(/6b) is an optical fiber collimator (lJa) ~ (/2
End face of e) and side surface for alignment of polygonal prism (7) (q)
It is a spacer prism that fills the gap between (tO) and (tO).

The reference surface (1) of the alignment side surface (9) of the polygonal prism (7)
One wavelength λl, λko, λJ on the side closer to 71.

An optical fiber collimator (t2FL) with a built-in optical fiber terminal (ta) through which light of As propagates is installed, and the other side for alignment (lO) has a demultiplexed wavelength λl,
Optical fiber collimators (/lb) to (/:le) equipped with optical fiber terminals (tb) to (ie) for receiving the light of λ, λJ, and λda are parallel to the reference plane (za). be installed in order. The distance between the mutually parallel alignment side surfaces (q) and (to) of the polygonal prism (7) (Ll is one cylindrical sleeve (Zaa) ~ (/, ?e), where the outer diameter of each is (D), the following formula It is determined by

L = 0) D / θ At this time, the light enters the polygonal prism (7) parallel to the reference plane. The pitch (Pl) of the light traveling through multiple reflections between the alignment planes (q) (to) is equal to the outer diameter (Di) of one cylindrical sleeve (Zaa,) to (/Jo). By arranging each component with smooth piping and mechanically aligning each component using the reference plane (ffl) as a reference, the optical fiber collimator (/lb) ~ (zae
The pitch of the optical axis of ) is (DJ), and the pitch of the optical axis of the polygonal prism (7
) matches the pitch of the optical path (Pl).

With the above configuration, the light including wavelengths λl to λ that has propagated through the optical fiber (/a) is transferred to the optical fiber collimator (Z
aa) into a parallel beam of light and enters B P F (Jl. Here, B P F (, 7) transmits only the light of wavelength λl and reflects the light of other wavelengths. This transmitted wavelength λl The light enters the optical fiber collimator (t2b) K. At this time, since the optical axis of the optical fiber collimator p (Zaa) and the optical axis of the optical fiber collimator (/Jb) coincide, the optical fiber collimator (llb) ) The incident light of wavelength λl is coupled to the optical fiber (lb).On the other hand,
The wavelengths λko and λJ reflected by BPF(j).

The light of λ- is reflected by the mirror (11) and becomes B P F (4t
Inject into +. Here, B P F (el transmits only light of wavelength λ.

Light of other wavelengths is reflected, and the transmitted light of wavelength λ enters an optical fiber collimator (IIC).

At this time, the pitch (Pl) of the light that is folded back through multiple reflections in the polygonal prism (1) and the pitch (DJ) of the optical axes of each fiber collimator are the same, so it is incident on the optical fiber collimator (t2c). The light with the wavelength λ is coupled to the optical fiber (tC). In the same manner, the light with the wavelength λ3 is coupled to the optical fiber (ld), and the light with the wavelength λ is coupled to the optical fiber (ze): !Thus, the wavelength J/~
The light of λda is demultiplexed.

As described below, simply by mechanically pressing and aligning each component such as the prism and optical fiber collimator against the reference surface (7), there is no need to move or adjust each component individually. Gatsu, without observing the light combining beak,
Light@adjustment can be achieved.

In addition, the side surface (lO) of the polygonal prism (ri) for lJ
In addition to the dielectric interference filter film, the B P F (, 71 paulownia 6) formed on the dielectric interference filter film may be attached to a thin transparent plate %-jfd surface (10) covered with a dielectric interference filter film. Also.

It goes without saying that the number of demultiplexes is not limited to 11.

Figure 2 shows another embodiment in which each component is aligned and fixed.
, 2a) ~ (tle), spacer prism (lyoa) (
tsb), each component of gummy (L) is arranged on an alignment substrate (Zaa) with an L-shaped cross section, and another alignment substrate (t6b) is placed on top and mechanically sandwiched. This achieves optical axis adjustment and fixation of each component. In this way, we prepared two alignment substrates with L-shaped cross sections (/l
, a) (/6b) is used.

Alignment work can be done easily. Furthermore, if the entire arrangement is fixed after performing such alignment work, one alignment substrate (iA
a) (tAb) serves as a protective member that covers each component from the surroundings, and also serves as a case.

In addition, although the case of the optical wavelength demultiplexing apparatus which performs demultiplexing of optical wavelength was explained at least one, this invention is not limited to this, and the optical wavelength multiplexer which performs multiplexing of optical wavelength.

Alternatively, the present invention may be applied to an optical wavelength multiplexing/demultiplexing device that combines these functions. Furthermore, by using a half mirror instead of a filter, the present invention may be applied to an optical distribution device that divides the power of light.

〔Effect of the invention〕

As is clear from the above description, this invention uses a polygonal prism provided with a bandpass interference filter, and mechanically presses and aligns each component such as the prism and optical fiber collimator against a reference plane. Optical axis adjustment and assembly can be achieved through simple operations, and there is no wasted space.

[Brief Description of the Drawings] Fig. 1 is a side sectional view of one embodiment of the present invention, the calculation diagram is an exploded perspective view of another embodiment, and Fig. 3 is the arrangement of main parts of a conventional optical wavelength demultiplexing device. It is a diagram. (ta') ~ (te)...Optical fiber (optical fiber terminal), (,71(4')(,tl(41...Bandpass interference filter, (7)ψ/Polygonal prism, (g)/
・Reference plane, (q>(io)... side surface for alignment (1/)
a m mirror, (/comi) ~ (i2e)... optical fiber collimator, (/3a) ~ (tJe)... cylindrical sleeve, (/4'a) ~ (i'le) --- gradient index lens , (tsa)(/!rb')·φ spacer prism In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (3)

[Claims] (1) A polygonal prism consisting of a reference surface and two alignment side surfaces that are at a constant angle with the reference surface and parallel to each other, mirrors and a plurality of bandpass interference filters formed on each of the two alignment side surfaces. and a plurality of optical fibers which are formed by inserting mutually coupled optical fiber terminals and a gradient index lens into a cylindrical sleeve, and which are aligned with the alignment side surface via a spacer prism with the reference plane as a reference. An optical wavelength demultiplexing device comprising a collimator and. (2) The outer diameter of the cylindrical sleeve is (D), the angle between the reference surface and the alignment side surface is (θ), and the distance (L) between the two alignment side surfaces is L=0.5D/cosθ An optical wavelength demultiplexing device according to claim 1. (3) The optical wavelength demultiplexing device according to claim 1, wherein a polygonal prism and an optical fiber collimator are aligned and fixed between two alignment substrates each having an L-shaped cross section.